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Prev Professional Automotive Repair Technical Discussions for February 18, 2010
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Open Help Requests for GM
Help Request Answers
1995 Buick Park Avenue 3.8L horn VIN: 1G4CW52K6S
Thanks to all for your help.This car was just perchased and found the horn not working. Checked out system and found the relay was removed.Replaced relay and horn on all the time.Pulled steering wheel and all looks good.Is the horn circuit part of the clock sp...
2002 Cadillac DeVille 4.6L state insp failure VIN: 1G6KD54Y42
hello cady gurus i need a little help !! the codes indicate serial data line shorted to Bat + or no comm to several modules !! i scope the data buss term # 2 data link connector and pin 59 on pcm and get a sporadic square wave 0 to 7 + volt it shows a flat lin... Trouble codes: U1040 (loss ebc traction module), U1064, U1065, U1066, U, 1096 (loss of comm w/ipc), U1192
2008 Cadillac CTS 3.6L Pedestrian Impact Detection Module VIN: 1G6DR57V68
Hello, Today the car came in with a dtc B1000 in the Pedestrian Impact Detection Module. I already replaced this module for two times. The first time it had dtc B1000 set as current, so I did the diagnostic check, and that told me to replace the module. So wh...
1995 Chevrolet Camaro 3.4L Poor Idle Quality, Stall, HIGH IDLE VIN: 2G1FP22S6S
vehicle came in a year or so ago and a new engine was installed and then the custoemr decided not to pay so the car sat for about a year now he wants to pay so we decided to fix it. after installation of all misc components to allow vehicle to be fully assembl... Trouble codes: 35 (high idle possible iac problem)
2002 Chevrolet Malibu LS 3.1L parking lamps VIN: 1G1NE52J52
Got one here that intermittantly turns park lamps on. Vehicle recently in for t-stat replacement. Customer states vehicle had no electrical problems before service. Lights are controlled by bcm. Bcm turns ground on for relay. Unplug bcm and lights stay on.unpl...
2002 Chevrolet S10 4.3L brake light VIN: 1GCCS19W92
customer came in with brake lights staying on, checked and unplugged brake light switch but nothing changed. put directional on and lights will respond. when 4way flasher is pressed, the lights stay lit on the dash and no change in the rear lights need help th...
2003 Chevrolet Malibu 3.1L back-up lights
When this car is put in reverse the back-up lights flash,you can hear the relay clicking also. This only happens when the car is running,not with just the key on engine off. Switched relays with no change. Check on the body module showed no codes. Tried extra ...
1999 GMC K1500 Suburban 5.7L MIL Lamp on VIN: 1GKFK16ROX
hello all, have a real problem 5.7 here. i have read through all the postings, followed all tests and am still stumped. just did leaking lower intake gaskets on this one, on test drive found it to be very low on power. replaced plugged fuel filter and fuel pum... Trouble codes: P0171, P0174
2001 GMC Yukon XL 1500 SLE 5.3L Poor Idle Quality, Misfire, no power VIN: 1GKFK16T31
came in for shaking and no power found code p0300 just to check put in a set of plugs did not fix prob when looking at missfir data it shows that cyl 2 4 6 8 all missing that is thw whole pass. side # 6 and 8 seem to be the worst fuel pressure is 65 psi swappe... Trouble codes: P0300
2003 GMC Yukon Denali 6.0L Poor Idle Quality, Misfire, Poor Fuel Economy, MIL Lamp on VIN: 1GKEK63U43
this denali is killing us. after a simple tune up and mass air flow sensor replacment and replacing the intake manifold assembly (burned through from shorted knock sensor harnness) causing vacuum leak. we replaced both knock sensors amd harness from gm.we did ... Trouble codes: P0101, P0171, P0174, PP300, P0327, P0332
2004 GMC Sierra 1500 5.3L Misfire, MIL Lamp on VIN: 2GTEK13TX4
Any help would be apprieciated. This vehicle came in with a miss and lean code on bank one. I checked fuel press. 62 P.S.I. I also checked for vaccume leaks and found none. Checked TSB's And O2 sensor not cracked. Cyl. 1,3,5,7 misses inter with 1,5 missing all... Trouble codes: P0300 (Engine miss), P0171 (Lean Bank One), P0131 (HO2S Low Voltage Bank 1 Sensor 1)
2003 Hummer H2 6.0L Headlights VIN: 5GRGN23023
I know this is probibly an easy fix for someone, how do you set the headlight horizontal aim, I can get the vertical adjustment correct but not sure on the horizontal on this vehicle. Jim in Quincy CA [...]
2004 Oldsmobile Silhouette GL 3.4L cooling fan VIN: 1GHDX03E24
gm tech, please help. car came in with a overheat (3/4 temp) problem, temp will drop once heat is on. pressure test cooling system, no external leak. we see cooling fan will on if a/c is on. so we decide [...] replace temp sensor and thermostant, same problem. ch...
2000 Saturn LW2 3.0L MIL Lamp on VIN: 1G8JW52R3Y
Hello...I have a p0154 no activity on bank 2 sensor 1 code. The stft is -2 to+1. The Ltft is 0. The lamda reading is 985. I have checked the pumping output and pumping input wire with the AF sensor disconnected. They both read .3 at the AF sensor connector. I ... Trouble codes: P0154

Fixes & Summaries for GM
Fix/Summary Answers
1991 Buick Century Special 3.3L No Start VIN: 1G4AH54N8M
when I was testing for bad inj. pulse I pulled 1 at a time and I had 3 bad inj. so I pulled off all inj. and check for pulse and it was good replaced 3 inj. and runs great thank you everyone for all the help this is a great site
1999 Buick LeSabre Limited 3.8L HVAC display VIN: 1G4H52K2XH
I would like to thank all that reminded me to check the owners manual. The procedure to change it from metric reading to American readings took care of the problem.
2004 Cadillac SRX 3.6L unknown VIN: 1GYDE63744
hi all techs: open the transfer case apart,nothing found obviously wrong. However,we found the drive shaft bearing is kind of siezed. we sent the driveshaft out for repairs,but the reman guy only put grease in it. However,put everything back together the noi...
1999 Chevrolet Cavalier Z24 2.4L Misfire, MIL Lamp on VIN: 1G1JF12T6X
Well I like to thank all that gave the time to help. It turn out that the wiring harness connector was the bad seed. I had good voltage at the harness and injectors were new but when put together to make connection it pushed the wire terminal back and cause ... Trouble codes: P0302 (Misfire Cylinder 2).
2000 Chevrolet Blazer LS 4.3L Hesitation, Cuts out, Misfire VIN: 1G4FH879WY
Figured the problem. I hooked up the scope to the crank sensor signal and watched wave forms- They looked consistant and clean at idle, as rpm increased the wave forms were starting to look like a title wave and kept getting more inconsistant, however the wave... Trouble codes: P0300 (Multiple misfire).
2001 Chevrolet Tahoe LT 5.3L No Start VIN: 1GNEK13T01
Thank you all so much for the advice. Again the problem here is that it will never act up for us while in the shop. What I was looking for was a pattern frailer so if we needed to do an educated repair (guess by % of success) we wouldn’t overlook something. Al...
2002 Chevrolet Trailblazer LS 4.2L Actuator VIN: 1GNDT13S92
thanks for everyone's help. The fork was broken on this one. Everything else looked pretty good, bearings and stuff, so thru a new fork in it and it works great. Thanks again everyone !!!
2002 Chevrolet Blazer LS 4.3L Stall, Misfire, MIL Lamp on VIN: 1GNCS13W52
I actually repaired this vehicle the same day. i took the crank sensor out and it had been contacting the ring.(just like edward had mentioned) i replaced it and the customer is driving happily. i do thank each and every one of you for you suggestions, it is s... Trouble codes: P0101, P0327, P0335, P0341.
2004 Chevrolet Suburban 1500 Z71 5.3L Stall, MIL Lamp on VIN: 3GNFK16Z44
The Suburban is fixed! Thanks to all of you who responded. Barry [...] Ohio put me in the right area. He suggested that I look for a ground from the RIGHT cylinder head to the coil bracket. There was none,however I did notice a ground wire breaking out of the h... Trouble codes: C0207 (tps or rear wheel speed sensor).
2006 Chevrolet Express 3500 6.0L engine VIN: 1GCHG35U56
2006 Chevrolet Trailblazer LT 4.2L MIL Lamp on
The customer needed to take their vehicle. I have not found the problem yet. Fuel pressure and volume are okay. This only has one bank. I do not have a smoke machine. i have tested many different ways for vac leak but have not found one(carb spray, water, ... Trouble codes: P0171 (system lean bank 1), P0455 (evap large leak).
2001 GMC C-Series Topkick C6H042 7.2L No Start VIN: 1GBK6H1C61
We changed the engine oil and oil filter and after 2 weeks the engine has been starting ok hot and cold. Thanks to all.
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