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International Automotive Technicians Network
Prev Professional Automotive Repair Technical Discussions for June 28, 2012
International Automotive Technicians' Network (iATN) - Members Only
(Also Available: All, Asian, Chrysler, European, Ford, GM.)
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Open Help Requests for GM
Help Request Answers
1997 Buick LeSabre Custom 3.8L Stall VIN: 1G4HP52K4V
the vehicle cam in for a hessitation has 150xxx miles recomended a tune up performed the tune up an the car idled high had a mass air flow code and throttle postion code replaced both an car still idled high found some vaccum lines with cracked conections and ...
2003 Cadillac CTS 3.2L Hesitation, Cuts out, Misfire, MIL Lamp on VIN: 1G6DM57N13
we have tested all app and tps readings unable to duplicate readings that indicate an issue. have performed wiggle with no response. checked all ref voltage. very hard to duplicate with out driving Trouble codes: P0221, P0700, P2176, P2135, P0121
1991 Chevrolet C3500 Cheyenne 7.4L rr drum brake VIN: 1GCHC34N4M
Have a pickup with RWAL that has a RR brake grabbing. the brake pedal is very sensitive. Inspected the brake hardware and drums the hardware, shoes and drums look like they have been serviced recently but they haven't the drums are clean and not out of round, ...
1999 Chevrolet K3500 6.5L Excessive Emissions, Surge VIN: 1GBJK34F4X
Symptoms: Vehicle came in with intermittent black smoke from the exhaust while driving on steady acceleration. Checked computer for diagnostic trouble codes, four p0219 and p0226 followed testing for p0226 and everything tested as normal because of the intermi... Trouble codes: P0219, P0226 (Accelerator pedal position sensor 3)
2003 Chevrolet Silverado 1500 4.8L Misfire VIN: 2GCEC19V63
I hope you guys can steer me in the right direction because I think I've hit a brick wall.This truck has missfires when cold(or after it has sat for 1/2 hour).Only missfires on the right hand cylinders(bank#2).Cylinder #6 is by far the worst.The missfire goes ... Trouble codes: P0300
2004 Chevrolet Silverado 2500 HD 6.0L Stall VIN: 1GBHK24U14
This was a no start or start and die like vtd. To start we accessed all modules and found that there was no communications with bcm.Went to pcm and found vehicle would start with inactive showing and then active and vehicle would die. Check power and ground to... Trouble codes: P1626
2004 Chevrolet Trailblazer LS 4.2L Poor Idle Quality, Misfire, MIL Lamp on VIN: 1GNDS13S84
Hello iATN members, this Trailblazer is driving me nuts. First it came in with 2 misfire codes cyl. #2 & #5, replaced coils and it was fine for a week then it came back with cyl. #1 misfire, I have done everything posible, compression test, new plugs, 3 coils ... Trouble codes: P0300 (Randome misfire), P0301 (Cyl. 1 misfire)
2007 Chevrolet Suburban 1500 LTZ 5.3L Bcm VIN: 3GNFC16J77
Ok here's one for all the GM gurus out there. One of my techs replaced the battery in this vehicle and now it will not start. He utilized a memory saver, but after the battery was swapped and it wouldn't crank, I ran all the fuses and found the cigarette light...
2008 Chevrolet Uplander LS 3.9L abs VIN: 1GNDU23W98
vehicle has low speed trac light ilumination in information display abs pump can be heard happens without foot on brake pedal when leaving from a stop. no codes present visual inspection has revealed nothing.
2007 GMC Acadia SLT 3.6L Timing Chain VIN: 1GKER23767
We have a 07 Acadia 3.6L with a timing chain rattle on start up which lasts for 20-30 seconds so did some research to find that these engines have trouble with timing chains. We flushed the crankcase to make sure it wasn't sludge build up from the long oil cha...
2004 Pontiac Grand Am GT 3.4L engine VIN: 1G2NW12EX4
Has extended crank after fueling, no other time. She always fills the tank when fueling, if below 1/2 tank, is worse. Seems to run rough for a few seconds after starting. Sounds like vapor entering engine while fueling, has no codes and valves all seem to be w...
2004 Pontiac Vibe 1.8L MIL Lamp on VIN: 5Y2SL628X4
Customer complains of CEL with an intermitant rough idle. P0171 continues to return, freeze frame data shows low RPM loaded with speeds from 10 -40 mph with stft of 5-10% and ltft of 30-40% when setting code. O2 sensors are both active. We have flushed injecto... Trouble codes: P0171 (Fuel system lean bank 1)
2004 Saturn Ion-1 2.2L wipers VIN: 1G8AG52F44
wipers phantom wipe when key is turned on -wiper switch off or unplugged .wipers only work on high and dont park .ground at motor good,same one for relays.scanner shows bcm activating relay command when phantom wipe. so something activating bcm when off and wo...

Fixes & Summaries for GM
Fix/Summary Answers
2001 Chevrolet Tracker LT 2.5L Cuts out VIN: 2CNBE63431
Thanks for all the info. Have not seen the car back for repair. Called the guy from back east, he was very helpful. When car returns we will be using him.
2003 Chevrolet Impala LS 3.8L high idle VIN: 2G1WH52K43
problem was bad ecm,installed new ecm and programmed. thanks for the help
2007 Chevrolet Silverado 2500 HD WT 6.0L Hesitation, MIL Lamp on, Reduced power VIN: 1GCHK24K27
This truck is fixed! Found wiring rubbed through on the main engine harness where it crosses the bank 1 coil assembly,one of the bolt/studs rubbed it way though the conduit and was shorting to ground. there was some extra wiring weighting the harness down onto... Trouble codes: P0641 (5 Volt Reference circuit).
2007 Chevrolet Avalanche LTZ 5.3L No Start, Cuts out, Stall, MIL Lamp on VIN: 3GNFK12387
I have been over the harness back to front.Found no "holes" in the harness at all.Ordered a pcm connecter and found it is on back order.I have sprayed the pcm cnnecter with a connecter inhancing compound.This product is through worth.The truck has been road te... Trouble codes: P1516, P2119, P2135.
2001 GMC W4500 Forward W4S042 4.8L blower motor VIN: J8DC4B14X1
When we power up the fuses everything worked fine it has a loss of power from somewhere customer needed vehicle back for there work, found a manual for it when it comes back ill post update
2003 Pontiac Grand Prix SE 3.1L MIL Lamp on VIN: 1G2WK52J73
Sorry for the late reply; I got busy the past few weeks and forgot about this request. The car is fixed. It turned out that the customer installed CMP harness had been wired to the sensor wrong. I had checked for this very early on and verified their work, ...
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