In 2010, dieselengines sold in theU.S. are requiredto meet newEnvironmentalProtection Agency(EPA) emissions require-ments. To meet the standards for nitrogen oxide (NOx) reduc-tion, the new Duramax Diesel engines in full-size GM trucksand vans feature a Selective Catalyst Reduction (SCR) systemthat uses automotive-grade urea known as Diesel ExhaustFluid (DEF) that is mixed in the exhaust stream, causing achemical reaction that converts the gases into mostly nitrogenand water.

The DEF in the vehicle must be refilled periodically, similarto the fuel tank, but not as often.

Diesel Emissions ControlThe SCR after-treatment system on the new Duramax

Diesel engines causes NOx reduction reactions to occur inthe exhaust stream. Its called selective because it uses ammonia as a reductant to reduce NOx levels within acatalyst system.

The Engine Control Module (ECM) controls the DEF delivery

system. Based on theengine NOx emissionslevel communicated tothe ECM by the NOx

sensors, the ECM willsend a command to the DEF

injector to dose a given quantity of DEF. The injected DEFcombines with the exhaust gas with the help of mixers beforecontacting the SCR. The SCR brick stores the ammonia andthrough a chemical reaction with the NOx in the exhaust gasproduces nitrogen (N2), water (H2O) and small amounts ofcarbon dioxide (CO2), which are natural elements commonin the air.

Diesel Exhaust FluidDEF is a colorless, clear solution of water and urea that has

32.5% +/- 0.7% of urea by weight.DEF also is referred to by other names such as AdBlue,

ClearBlue, Urea, and Aus32 (Aqueous Urea Solution).The recommended temperature for storing DEF is between

12F 86F (-11C 30C). To prevent DEF decomposition,it should not be transported or stored at temperaturesabove 77F (25C). The shelf life of DEF depends on storage

ON THE WEB

www.acdelcotechconnect.com, clickthe TechConnect Magazine link, or

Log in to the ACDelco LMS, click theResources link

Clean Diesel Exhaust Chemistry . . . . . . . . .1

Summer Maintenance Tips . . . . . . . . . . . . .1

DuraStop Performance Brake Pads and Rotors . . . . . . . . . . . . . . . . .2

New Brake Seminars: Hybrid Technology to Basic Diagnosis . . .3

ACDelco Merchandising Materials Focus on Marketing to Women . . . . . . . . . .4

New ACDelco Belt Wear Tool . . . . . . . . . . .5

TSS Q&A . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Duramax Diesel Water Pump Cover . . . . .6

Tech Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Training Update . . . . . . . . . . . . . . . . . . . . . . .8

IN THIS ISSUE

May & June 2010

continued on page 4

Summer Maintenance TipsMany drivers around the country are

in the midst of spring fever, rollingdown the windows and turning up theradio, but when it comes to the actualvehicles theyre driving, signs of winterare probably still hanging around. Checkthe fluids or tires? Change the air filteror wiper blades? Spring is the perfecttime for a maintenance check-up ofthese items and many others.

Remind your customers that the following items require regular inspection or maintenance:

Automatic transmission fluid Battery and cables Belts Cabin air filter Chassis lubrication Engine air filter Engine oil and filter Exhaust Fuel filter Hoses Lights

continued on page 5

Clean Diesel Exhaust Chemistry

Power steering fluid Tire inflation and condition Windshield washer fluid Wiper bladesInclude these tips about some

items hardest hit by winter weather inyour maintenance discussions with customers.

Low Tire PressureA long, cold winter may have led to

a less than diligent check of tire pres-sures by many customers, resulting inadditional tire wear. Point out how tocheck the tire tread for uneven or irregular wear as well as cuts or bruisesalong the sidewalls that may havebeen caused by potholes. Explain thatuneven tire wear may be a symptom ofworn suspension components.

Worn Belts and HosesCheck belts for looseness and worn

conditions. Replace a belt whencracked, frayed, glazed or showing

2Volume 17, Number 3 (TS-PU-0015-10)ACDelco TechConnect is published bi-monthly andonline for technicians of Total Service Support(TSS) and Key Fleet accounts to provide timelyservice information, increase knowledge andimprove the performance of the service center.ACDelco 360 represents our mission to look atour businesses at every possible angle to providevalue and assistance to our distributors andtheir customers as well as offer a full circle ofsupport with programs, tools, training andmarketing focused on enhancing and growingour partnership successfully.

Publisher:Mike DeSander

ACDelcoE-mail /

mike.desander@gm.com

Editor:Mike Militello

ACDelcoE-mail /

michael.militello@gm.com

Technical Editor:Mark Spencer

E-mail /mspencer@gpworldwide.com

Production Manager:Marie Meredith

Desktop Publishing:5by5 Design LLC

E-mail /dkelly@5by5dzign.com

Write to:*ACDelco TechConnectP.O. Box 500Troy, MI 48007-0500

On the Web::To read and search recent issues ofTechConnect online: www.acdelcotechconnect.com,

click the TechConnect Magazine link, or

Log in to the ACDelco LMS, clickthe Resources link

ACDelco service tips are intended for use by professional technicians, not a do-it-yourselfer.They are written to inform those technicians of conditions that may occur on some vehicles, or toprovide information that could assist in the properservice of a vehicle. Properly trained technicianshave the equipment, tools, safety instructions andknow-how to do a job properly and safely. If a con-dition is described, it cannot be assumed that theinformation applies to all vehicles or that all vehicleswill have that condition.All materials and programs described in this magazine are subject to change. Submission ofmaterials implies the right to edit and publish.Inclusion in the publication is not necessarily anendorsement of the individual or the company.TechConnect is published for ACDelco by SandyCorporation, Troy, MI.

2010 ACDelco. All rights reserved.

DuraStop Performance BrakePads and Rotors

Aggressive stoppingpower in a heavy-duty useenvironment is a require-ment for any brake materi-als used on police and fleetvehicles. However, not allheavy-duty parts can mea-sure up to the demands ofdaily use in police patrolvehicles.

ACDelcos new DuraStopPerformance brake padsand rotors are designed todissipate heat quickly forexcellent braking controlwhile offering durable, longlife performance.

The DuraStopPerformance brake padsare available for 2006-2010Chevrolet Impala, 2003-2010 Ford Crown Victoria,2006-2010 Dodge Chargerand 2007-2009 Chevrolet Tahoe models. DuraStop Performance pads will use thenew PV suffix, which refers to Performance Vehicle.

DuraStop Performance brake rotors are available for 2006-2010 Chevrolet Impala,2003-2010 Ford Crown Victoria, 2006-2010 Dodge Charger/Challenger, and 2007-2009 Chevrolet Tahoe models.

D3EA PPSV TestedDuraStop Performance brake pads are tested to the rigorous

Dual Dynamometer Differential Effectiveness Analysis (D3EA) testcriteria for Police and Public Service Vehicles (PPSV). The testingcriteria specifically targets police fleets and compares frictionresults of wear, heat dissipation, effectiveness, brake fade andhigh-speed performance. The high-speed testing isolates theeffects of the driver, road and tires.

The DuraStop Performance brake pads, specifically manufactured for police fleetapplications, are more durable and quieter than competitive pads and are speedrated to assure confident high-speed braking. In testing, competitive pads had morethan twice as much wear at 350 degrees (normal braking temperature) and twice asmany stops above 70 deci-bels than the DuraStopPerformance pads.

Designed to work withDuraStop Performancebrake pads are DuraStopPerformance rotors, whichwill last longer than stan-dard OE rotors in policeapplications. DuraStopPerformance rotors aremanufactured using dampediron to resist and dissipateheat better than standardG3000 rotor iron. The rotorsalso use an enhanced vaneconfiguration to assure quick heat dissipation.

The rotor also is coated with a material that covers the entire surface of the rotorto help resist corrosion better than standard coatings.

For more information about DuraStop Performance brakes and specific applica-tions, contact your local ACDelco distributor or consult the ACDelco parts catalog. Thanks to Kurt Pursche

Enhanced vane configuration assures quick heat dissipation

New Brake Seminars: Hybrid Technology toBasic Diagnosis

ACDelcos commitment to providing top quality technicaltraining continues with the release of five all-new modularbrakes seminars that cover the newest technologies of automotive braking applications. Designed to be offered asone-hour Lunch-and-Learn training events, they can be delivered as one-hour stand-alone courses or combined to provide advanced training for your shop.

Hybrid Regenerative Brake Systems S-BK05-04.01SEM

What exactly is regenerative braking? How does a hybridvehicle control module determine how much hydraulic brakeforce and regenerative brake force should be used to slow orstop a vehicle? How different are service procedures forhybrid vehicle braking systems compared to conventionalABS?

These questions andothers aboutGM, Ford andToyota regener-ative brake systems areanswered. Inaddition, detailsare providedabout high volt-age components, identification labels and Personal ProtectiveEquipment. As an added feature, innovative technology (suchas a power generating shock absorber) and other possiblefuture technologies are highlighted.

Traction Control and Stability Enhancement Systems S-BK05.02.02SEM

Modern tractioncontrol systemsand the variousstrategies used fortraction controlintervention, suchas corrective fuelmanagement, throt-tle closure, brakeapplication andspark table modifi-cation, are dis-cussed as well as the traction control switch, the brake tem-perature algorithm and brake pedal position sensor inputs.

Operation and diagnosis of stability enhancement systemcomponents, including the longitudinal accelerometer, steeringwheel position sensor, yaw rate sensor and lateral accelerom-eter sensor, also are discussed.

Specific service procedures highlight the brake pedal position sensor calibration, zero point calibration and yaw ratereference table resetting.

Antilock Brake Systems S-BK05-03.01SEM

Antilock brake systems (ABS), both integral and non-integral,and typical components of antilock brake systems are discussed in this seminar.

ABS sensor inputs, such as active and passive wheelspeed sensors, brake pedal position sensors, steering anglesensors and yaw rate/lateral accelerometer sensors, along

with applicable diagnostic procedures are key elements ofthis seminar. ABS subsystems and their operation, includingbi-state engine mount systems, dynamic rear proportioning,engine drag control, variable effort steering and vehicle stability enhancement systems, also are reviewed.

Foundation BrakesS-BK05-05.01SEM

This informa-tive seminarbegins withthe physics ofbraking andhow it appliesto replacementcomponentparts along withwhat D3EA certificationmeans to boththe customerand technicianinstalling theparts.

A modernbraking systemis comprised ofseveral subsystems, such as the power assist, apply,hydraulic, warning lamp, balance control and wheel brakessystems, and this seminar provides an in-depth discussion ofeach of these subsystems.

Single and dual-diaphragm power boosters are topics thatare also discussed along with hydraulic booster systems thatuse power steering pump pressure to increase hydraulic pressure within the master cylinder. DOT 3, 4 and 5 hydraulicbrake fluid properties and applications are additional elementsof this seminar. Hydraulic circuits and components also arereviewed as well as valuable brake system service tips.

Brake Noise Diagnosis and Service S-BK05-06.01SEM

The first step to customer satisfaction is identifying the customers concern successfully. To assist with this criticalprocess, this seminar provides a Brake System DescriptionQuestionnaire as an additional support tool, enabling a techni-cian to ask pertinent questions for effective diagnosis.

How to perform a thorough pre-road test inspection and aneffective road test are described in detail. Diagnosis informa-tion includes checking pedal travel as well as specific disc anddrum brake checks. In addition, diagnostic tips are provided forevaluating brake booster operation and noise concerns.

Learn MoreIn addition to the new brake system seminars, ACDelco offers24/7, on-demand, online, Web-based courses that can be completed at any time. These online courses complement theinstructor-led, hands-on courses that remain the core ofACDelco training. To review the latest training courses available, log in to the ACDelco Learning Management System(LMS) at www.acdelcotraining.com. Take the opportunity to expand your technical knowledge, contact your local ACDelco distributor to learn when ACDelcoseminars have been scheduled in your area. Thanks to Greg St. Aubin

3

In 2007, the Knowledge is Power program was launched tosupport an ACDelco Marketing to Women initiative in the field.The program includes many merchandising items, including acomplete animated presentation with presenter notes, a semi-nar guide with helpful hints on how to run a seminar, newspaperand radio advertising templates, winter and summer survivaltips, banners, posters, waiting room informational booklets andpost-seminar surveys.

temperature and exposure to sunlight. At a constant ambientstorage temperature of 50F, DEF may have a minimum shelflife of 36 months. But at a constant ambient storage tempera-ture of 86F, it may have a minimum shelf life of only 12months. DEF also freezes below 12F, but it may be reusedonce it thaws.

Before using DEF, be sure to check every batch of fluid forpotential evaporation.

Driver RequirementsThe operation of the after-treatment

system for NOx reduction is transpar-ent to the driver. There is no change invehicle performance or driveability.

The only requirement of the driveris to replenish the DEF when theinstrument cluster prompts to do soor at regular oil change intervals,whichever comes first. DEF usage isheavily dependent on drive cycles andwill vary from vehicle to vehicle.

The DEF fill location (identified by a blue cap) on GM full-size vans is next to the fuel filler and on GM full-size trucks ison the right rear side of the engine compartment. The nozzlediameter is smaller than the diesel fuel nozzle.

Use the J23688 refractometer to test for DEF dilution. IfDEF is contaminated with diesel fuel, the DEF system mustbe replaced.

If the diesel fuel is contaminated with DEF, the water-in-fuelsensor should detect the contamination. Follow the appropri-ate diagnosis and repair procedures in the ServiceInformation.

Driver WarningsA number of driver warnings will display on the Driver

Information Center to warn the driver that the DEF level isgetting low and should be refilled. Several messages indicatethe DEF mileage range that the vehicle will be able to travelbefore refilling.

A new DEF warning symbol also will flash on the instrument cluster to communicate DEF system warnings.

The Driver Information Center messages include: Exhaust Fluid Range: XXX displays available mileage

range when the DEF is getting low Exhaust Fluid Low Speed Limited Soon displays

when the DEF range falls below a specified range; speedwill be limited when the DEF level becomes critical

Exhaust Fluid Empty Refill Now displays when theDEF is empty; speed will be limited and other messageswill display that provide more information.

If these warning are ignored, additional warning messageswill display and the vehicle speed will continue to be severelylimited.

When adding DEF to an empty or very low tank, always addat least one gallon (3.78L) of fluid to release the vehicle fromspeed limitation.

DEF AvailabilityThe DEF infra-

structure is ex -pected to growover the next fewyears. DEF will bemade available atdealerships, fuel stations, truckstops (pumps aswell as small con-tainers), and otherlocations that sellautomotive fluids.

DEF is availablefrom ACDelco inone gallon, 10-4022(19286291), and 2.5 gallon, 10-4023(19286292), packages. Thanks to MikeMilitello

Clean Diesel Exhaust Chemistry continued from page 1

New DEF warningsymbol

After-treatment SystemA. Diesel Oxidation Catalyst (DOC)B. DEF injection and mixerC. Diesel Exhaust Fluid (DEF)D. Selective Catalyst Reduction (SCR)E. Diesel Particulate Filter (DPF)F. Exhaust cooler

DEF is available from ACDelco

ACDelco MerchandisingMaterials Focus on Marketing to Women

As much as these materials werecreated with women in mind as thetarget audience, they also serve as agreat education tool for all con-sumers. Please take advantageof these useful tools to help marketthe services of your service centerto all of your customers.

Visit acdelcoadvantage.com toimmediately download any electron-ic items or order any physical itemsfrom the eStore. Thanks to Kelly Grinnell

4

Automotive beltconstruction haschanged over theyears, resulting inlonger-lasting beltsthat dont showtheir age readily.For many years,

belts were made of Neoprene rubber. Since the late 1990s,belts have been constructed of more durable EPDM (EthylenePropylene Diene M-class) rubber.

Neoprene rubber could be inspected visually, with identifi-able signs of cracking, chunk-out and rib separation. However,EPDM belts wear out gradually and do not necessarily showthe same signs of wear, making inspection and determiningwhen its necessary to replace the belt more difficult.

EPDM belts wear much like a tire. Material is lost in thebelt grooves when a belt comes into contact with pulleys asit moves around the drive system. The weakened belt perfor-mance and reduced tension can lead to belt slip. Slipping beltscan cause severe vibration and a reduced ability to transmitpower, which often leads to inconsistent alternator perfor-mance or poor A/C system performance.

To assist in identifying when beltsshould be replaced, ACDelco hasdeveloped a belt wear inspectiontool. Tools (#35-MI-0149-09A) areavailable for ordering free of chargethrough the ACDelco e-store.Maximum order quantity is 25.Go to TechConnect MagazineOnline for tool instructions.

A belt wear sell sheet (#35-SS-0025-10) also is availablethrough the ACDelco e-store.It explains the differences between EPDM vs. Neoprene con-struction and how to look for material loss on EPDM belts.

The belt wear inspection tool is available through yourACDelco distributor or through your local ACDelco representa-tive as well.

For additional information about belt wear inspection, checkout the video on acdelcotechconnect.com. Go to: ProductInformation tab > Technical Product Service Aids >Accessories Belt Drive System (ABDS) Thanks to Chris Vermette

ACDelco belt wear inspection tool

Summer Maintenance Tips continued from page 1signs of excessive wear. Refer to the ACDelco belt wearinspection tool for more details. Not replacing a belt asrequired could cause a breakdown or serious engine damage.

Also inspect hoses at each oil change and replace whenleaking, brittle, cracked, swollen or restricted/collapsed. Usethe squeeze test squeeze the ends (within two inches) of ahose with your finger and thumb to check for electrochemi-cal degradation.

Wiper DamageWindshield wipers should be inspected for cracks, cuts,

tears, streaking and chattering. If the blades are not clearingthe windshield properly, clean the windshield and the rubberwiper blades. If this does not correct the problem, thenreplace the rubber elements.

Winter weather can result in the following wiper damage: Sand and salt used on roads for increasing traction and

ice control will cause the wiper blades to wear morequickly.

Rubber blades can be cut or torn when using ice scrapersor when pulling the blades off a frozen windshield.

Using the wipers to wear through frost and ice, insteadof allowing the defroster to melt the ice, can dull, nick ortear the rubber blades.

Banging wipers on the glass to remove ice and snowmay cause the blade to bend, dislodging the rubber andcausing potential scratching of the windshield.

Brake NoiseBrake noise is often associated with worn pads or poor per-

formance. Some brake noise is normal and differences inloading, type of driving, driving style and weather conditionscan make a difference in brake wear. During brake service,verify all metal-to-metal contact areas between pads, padguides, caliper and knuckles are clean and lubricated with athin layer of high temperature ACDelco Silicone BrakeLubricant, P/N 10-4019. Brake noise is caused by a "slip-stick"vibration of brake components. If the noise persists and isconsistently occurring, silicone brake lubricant may be applied

to the back of each pad. This allows parts to slide freely andnot vibrate when moving relative to each other.

The following noises are characteristics of braking systems: Squeak/squeal noise Occurs with front semi-metallic

brake pads at medium speeds when light to mediumpressure is applied to the brake pedal; may occur on rearbrakes during the first few stops or with cold brakesand/or high humidity.

Grinding noise Common to rear brakes and some frontdisc brakes during initial stops after the vehicle has beenparked overnight. It may be caused by corrosion on themetal surfaces during vehicle non-use.

Groan noise On vehicles equipped with ABS, a groan ormoan noise during hard braking applications or on loosegravel, wet or icy road conditions is a normal function ofthe ABS activation.

Battery LifeCorroded battery terminals can prevent proper battery

operation in all weather. Keep the terminals clean and makesure connections are secure.

Even though the cold weather months are hard on the battery, hot summer temperatures can be even tougher.Summer heat can shorten the lifespan of a battery. To ensureproper operation, check that the battery is securely mountedand connections are clean, tight and corrosion free.

When talking with customers about regular vehicle mainte-nance, be complete in your service recommendations. Focuson overlooked but required maintenance that has real benefitsto the customer. For example, many vehicles are equippedwith cabin air filters. If these filters are used beyond replace-ment time, they may impede airflow, decreasing A/C andheating performance.

Providing responsible services at the proper maintenanceintervals will greatly aid your service center in gaining repeatbusiness and additional repair services when required. Thanks to Mike DeSander and Mike Militello

New ACDelco Belt Wear Tool

5

A. Gauge sits above theribs on a good belt

B. Gauge sinks below theribs on a worn belt

The TSS Q&A provides answersto common questions receivedby the ACDelco CustomerSupport Center.

Q: How can I log in to the Exclusively Yours website?

A: To log in to the Exclusively Yours website:1. Go to acdelcotechconnect.com2. Click the Rewards link in the left corner in the

Incentives box3. Click the Click here to login link4. Enter your 10 digit User ID. This consists of your

EY number (6 digit number that begins with a 6)and, immediately following that, the last 4 digitsof the cardholders Social Security Number (SSN).

Q: How do I view my ACDelco purchases?

A: To view the previous months purchases:1. Follow all the website log in steps2. Click the Rewards tab located next to the

Home tab3. Select Reports from the drop down menu4. Click the ISC Performance link located in

the box

Q: How can I view a listing of the retailers thataccept my EY card?

A: For a complete listing of all of the retailers thataccept the EY card:1. Follow all the website log in steps2. Click the Click here to view the complete mer-

chant listing link in the top right corner3. Enter your card number in the space provided

Q: How can I view my EY card balance?

A: For your EY card balance:1. Follow all the website log in steps2. Click the How many points do I have now?

FIND OUT in the blue box on the right3. Enter your card number4. A pop up window will open. Re-enter your EY

card number in the top right corner5. Enter the random code in the box on the left6. Enter the security code located on the front or

back of the EY card in the box on the right

Q: I have never received an Exclusively YoursRewards card. How can I get my card?

A: Call 1-877-227-0956 to request a card. You will beasked a few security questions and your EY cardwill be mailed to you.

If you have any questions about the TSS program orany current ACDelco activities, contact the CustomerSupport Center at 1-800-825-5886, prompt #0.

Duramax Diesel Water Pump Cover

When changing the water pump on a 2001-2005 DuramaxDiesel engine, examine the water pump cover. If it shows signs ofcavitation, it should also be replaced.

A new ACDelco water pump cover for the 20012005 DuramaxDiesel is now available, part number 97228188. It does notinclude an O-ring.

Two available ACDelco water pumps include an OE water pump,part number 251-723, or an aftermarket water pump, part number252-838.

Cavitation DamageCavitation is the process where a bubble in a liquid (usually

caused by the pressure of the liquid falling below its vapor pressure) rapidly collapses, producing a shock wave. The shockwave is strong enough to cause damage.

Possible cavitation is most likely at the impeller blade of apump, where flow rates and turbulence may be high. Cavitationcan cause vibration and noise as well as pitting erosion and additional wear. The pitting accelerates the erosion because itincreases the turbulence of the fluid flow, which creates more cavitation and, eventually, may lead to pump failure. Thanks to Matt Gibbard

New ACDelco water pump cover

Damage from cavitation

6

7Allison Transmission Shift Conditions

The 2001-2007 Silverado Classic,Sierra Classic; 2007-2010 Silverado,Sierra; and 2003-2010 Kodiak andTopkick, equipped with the AllisonLCT1000 transmission (RPO M74,MW7) may have a delayed engagementor no engagement into Drive, a delayedengagement or no engagement intoReverse, or a range inhibit with severalpossible DTCs. These conditions maybe more pronounced in cold climatesduring a cold start.

When DTC P0701, P0751, P0756,P0761, P0843, P0848, P0873, P0877or P0894 set, it could indicate no orexcessively low pump pressure as aresult of a no prime or loss of primecondition within the transmission pump.Follow the diagnostic steps outlined inthe Service Information.

All of these DTCs, excluding P0894could be set due to a fluid service/filterchange, transmission service involvingremoving the pan, low fluid levelcaused by a leak, or long periods ofstorage.

Also check the transmission fluidlevel using the Hot Check Procedure.Low fluid level may cause any of thelisted DTCs to set, particularly during acold ambient and cold vehicle start. Incold climates, ensure the fluid level isat the top of the HOT band.

After checking the fluid level usingthe Hot Check Procedure, if any of theDTCs reset during a cold start, inspectthe internal suction filter for possiblecracks.

Replacing the TCM will not likely correct any of the listed DTCs or lowmain line pressure.

Inoperative, Intermittentor Noisy A/C

Some owners of GM vehicles maycomment that their A/C is inoperative,operates intermittently or is noisy. NoDTCs are set. After further investigationand diagnosis, it may be determinednecessary to replace the ThermalExpansion Valve (TXV). However, beforereplacing TXVs, always follow the A/CPerformance Diagnostic in the ServiceInformation to verify the valve perfor-mance and review the diagnostic tips.

The TXV meters the amount of liquidrefrigerant that can flow into the evaporator. Located at the evaporatorinlet, the TXV is the dividing pointbetween the high and the low pressuresides of the A/C system. As the refrig-erant passes through the TXV, therefrigerant pressure is lowered. Due tothe pressure differential, the liquidrefrigerant will begin to boil at the TXVoutlet before entering the evaporatorcore. This characteristic is observed as adrop in temperature between the TXVinlet tube and the evaporator inlet tube.

TXV Failure Modes Possible causes of inoperative or

intermittent A/C: Bulb Sensor

Temperatures on inlet and outlettubes Are the temperatures onboth sides (inlet and outlet tubes)of the evaporator thermal expan-sion valve tube at the expansiondevice similar? If yes, replace thedamaged or faulty thermal expan-sion valve.Pressures Are both the low sideand high side pressures within thespecified values? Refer to theappropriate HVAC zone diagnostic.

Incorrect refrigerant charge Diagnose and repair potential leakand/or fill A/C system with correctcharge.

Leaking interfaces (Incorrect fastening at TXV or seal damage) Apply correct torque or replaceseals if necessary.

System contamination Is the liquid line extremely cold at theexpansion device location andwarm beyond the expansion devicelocation? The expansion device isrestricted. Inspect for contamina-tion (brown, powdery residue ormetal flake) and replace TXV.

Possible causes of A/C noise: Leaking interfaces (Incorrect

fastening at TXV) Fill systemwith correct charge.

Incorrect refrigerant charge Fill system with correct charge.

Non-optimized TXV/evaporator/plumbing Verify ifnoise is being produced by the TXVor other A/C system components.

Brake Pedal Kickback1997-2007 Ford E-Series; 1999-2008

Ford F-Super Duty; 2000-2005 FordExcursion

Some vehicles equipped with theHydro-Boost brake booster systemmay exhibit a brake pedal kickbackand/or grabbing condition when applying the brakes that may be causedby contamination within the powersteering system.

Filter the power steering fluid byinstalling a temporary filter in the powersteering system in line with the powersteering hose. The filter needs to go inthe low pressure line that goes fromgear to cooler to reservoir, where itwould be most accessible.

After the filtering procedure is completed, if the brake pedal kickbackpersists, it may be necessary to replacethe Hydro-Boost brake booster.

The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusualservice repair, the TSS Technical Assistance Hot Line can help. Call 1-800-825-5886, prompt #2, to speak with a technicalexpert with the latest OEM information.

Diagnostic AssistanceFor free technical diagnostic

assistance and product informationregarding specific ACDelco products,contact these toll-free informationhotlines staffed by ASE-certifiedtechnicians:

Brakes 1-888-701-6169 (prompt #1)

Chassis 1-888-701-6169 (prompt #2)

Clutches 1-888-725-8625

Lift Supports 1-800-790-5438

Shocks 1-877-466-7752

Starters and Alternators 1-800-228-9672

Steering 1-866-833-5567

Wiper Blades 1-800-810-7096

Thermal Expansion Valve

8TS-PU-0015-10

How to Take ACDelco TrainingGo to www.acdelcotechconnect.comand click on the Training tab to log onto the ACDelco Learning ManagementSystem (LMS).

New TrainingThe following ACDelco training

programs have recently been madeavailable via the LMS:

S-DS11-04.01WBT Noise,Vibration and Harshness

This WBT course covers the theoryof vibration and reviews basic toadvanced vibration diagnosis. Topicsinclude usage of the Electronic VibrationAnalyzer (EVA), tools used to measurerunout and driveline working angles,and other current tools.

S-DS11-05.01WBT Waterleak andWindnoise Management

This WBT course covers how to identify and repair vehicle water leaksand wind noise concerns. It covers general leak testing, adjusting leakingcomponents, door adjustments, androof adjustments.

S-EM01-01.01WBT EngineMechanical Diagnosis andMeasurement 1

Part one of this two-part WBT coursecovers basic engine mechanical concepts, including inspection, disas-sembly and assembly of the overheadcam and camshaft, crankshaft, pistonand rods, cylinder head, engine blockand valve train.

S-EM01-02.01WBT EngineMechanical Diagnosis andMeasurement 2

Part two of this two-part WBTcourse continues the introduction tobasic engine mechanical concepts, disassembly and assembly procedures,component measuring, and enginenoise diagnosis.

S-EP08-81.03WBT Duramax 6600Operation, Service and Diagnosis 1

This WBT course is intended forexperienced engine/driveability servicetechnicians, focusing on the Duramax6600 LB7, LLY-LBZ and LMM dieselengines. It covers engine operation,performance and major subsystem integration, including the fuel system,engine management system, exhaustafter-treatment system and electronicengine controls.

S-EP08-82.01WBT Duramax 6600Operation, Service and Diagnosis 2

This WBT course is intended forexperienced engine/driveability service

Course Number Course Name

S-AC07-02.01ILT Automotive Air Conditioning: Advanced Refrigerant SystemDiagnostics

S-AC07-03.01ILT HVAC Control System Operation and Diagnostics

S-AC07-06.01ILT Toyota HVAC

S-AC07-07.01ILT Chrysler HVAC

S-BK05-01.01ILT Braking Systems

S-EL06-04.02ILT Network Communication Diagnosis

S-EL06-10.02ILT Electrical Power Management

S-EL06-11.01ILT Automotive Electrical Circuit Diagnosis and Repair

S-EL06-12.01ILT Hybrid Technology and Service

S-EP08-02.01ILT Engine Performance: Computer Controls and Ignition SystemDiagnostics

S-EP08-03.01ILT Engine Performance: Air Induction and Fuel System Diagnostics

S-EP08-04.01ILT Engine Performance: Fault Monitoring and Emission SystemDiagnostics

S-EP08-05.01ILT Engine Performance: Advanced Drivability Diagnostics

S-EP08-20.01ILT Toyota Engine Performance

S-EP08-21.01ILT Chrysler Engine Performance

S-EP08-81.01ILT Duramax 6600: Diesel Engine Performance

S-SS04-01.01ILT Vibration Correction Diagnostics

S-ST10-01.01ILT Supplemental Restraint Systems

technicians. The course continues toreview Duramax 6600 LB7, LLY-LBZ andLMM engine operation, performanceand major subsystem integration.Diagnosis information covers the fuelsystem, engine management system,and exhaust after-treatment system.

S-FN00-20.01WBT MultipleDiagnostic Interface (MDI)Familiarization

This WBT course covers commoncharacteristics of the MDI, includingMDI Setup Software, MDI/On Vehicleoperation, and the Service ProgrammingSystem procedure.

S-MT03-01.01WBT All WheelDrive/Four Wheel Drive Systems

Intended for experienced driveline andtransmission service technicians, thisWBT course covers construction and

operation of All-Wheel Drive, part-timeand full-time 4-Wheel Drive, Automatic4-Wheel Drive, and the propeller shaftand front axle assembly.

S-MT03-02.01WBT ManualGearbox and Clutch

This WBT course reviews the manualgearbox and clutch assembly, includingthe transverse mounted gearbox, clutchassemblies, clutch control, synchroniz-ers and electrical components.

S-SS04-06.01WBT SteeringSystems and Diagnostics

This WBT course covers basic steering gear sets as well as manualand hydraulic steering systems. Theelectronic power steering system isintroduced, along with the Hybrid parallel steering system. Steering system service also is covered.

Current Instructor-Led TrainingACDelcos Instructor-Led Training (ILT) courses provide hands-on instruction on

the latest automotive systems. The following ILT courses are currently being heldat training center locations around the country. Click the Schedule link on theLMS Menu to search the latest training schedule for courses held in your area.