GM Automotive Technicians Technical Discussion and Fixes for Jul 20, 2004

Join Now

Prev	Professional Automotive Repair Technical Discussions for July 20, 2004 International Automotive Technicians' Network (iATN) - Members Only	Next
(Also Available: All, Asian, Chrysler, European, Ford, GM.)
Vehicle Owners: If you are seeking an automotive repair professional to service your vehicle, visit the iATN Repair Shop Finder.

Open Help Requests for GM

	Help Request	Answers
	1988 Buick Electra Limited 3.8L cam ckt VIN: 1G4CW51G8J Hi All, I have a this vehicle here that is giving me much concern. It has a code 41 which is the CAM sensor circuit. I measured the voltage between terminals A-B which was 5 volts and should be approx.8-11volts and B-C which was 11 volts of the CAM sensor conn...	View
	1977 Cadillac Seville 5.7L rear air suspension VIN: 6S69R70494 The customer called and said the rear is completely down. Before I check into, does anyone have basic info on how the vacuum operated lift compressor operates? May simply be a line leak to rear but would like some advanced info before getting towed in. No prev...	View
	1987 Chevrolet R10 Custom Deluxe 5.0L Poor Idle Quality, Cuts out, Stall VIN: 1GCDR14H2H vehicle stalling when put in gear or sometimes when put in gear	View
	1991 Chevrolet Corvette 5.7L pcm communication VIN: 1G1YY2389M this car is giving me static, could use a little help as im not big into vettes and dont really understand the whole ccm thing but see that it acts just like a bcm. the problem is that the sys light comes on just as soon as you start the car, it goes into limp...	View
	1993 Chevrolet Camaro Indianapolis 500 Pace Car 5.7L power steering VIN: 2G1FP22PXP well after getting the engine started and all I found the P/S did not work (no assist) replaced the P/S pump with a A1 reman along with the A/C compressor because it was leaking. After filling the P/S back up and starting the vehicle the P/S pump was now wor...	View
	1994 Chevrolet S10 4.3L Poor Idle Quality, Hesitation, Stall, Misfire VIN: 1GCCS19WOR Neighbor's truck (I am recovering from open heart surgery) Sent to anther shop.They have replaced ign module,intake gaskets,distributor,rotor and cap,spider injector,spark plugs and wires,coil,knock sensor,ECM prom,idle valve and MAP sensor.Fach seemed to impr...	View
	1994 Chevrolet S10 Blazer Tahoe 4.3L Poor Idle Quality, Misfire, MIL Lamp on VIN: 1GNDT13W5R our problem is that the egr valve keeps getting wedged open with carbon. every time the customer takes the vehicle, it's back in a week with the same problem,and of course we drive it and it doesn't happen. does any one know why after cleaning the motor this p... Trouble codes: 32 (egr system problem)	View
	1995 Chevrolet C3500 Cheyenne 7.4L chassis VIN: 1GCHC39N6S customer concern regarding grinding sound while moving. Truck is used for lawn care and loaded with water tank and pump. while driving customer complains of grinding noise when turning right and some times while driving straight. Noise stops when driving and g...	View
	1997 Chevrolet C1500 Suburban 5.7L system VIN: 3GNEC16R3V doing this one for a co worker he replaced the comp. with reman no help than he replaced with a new delco each time ck. the orfice tube was ok . cleaned and flush blew whole system out . outside temp 99 . replaced cond. and dryer again . no help heter contol v...	View
	1998 Chevrolet Express 2500 LS 5.7L abs VIN: 1GCGG25R1W this vehicle came in with 4 abs codes 35,36,37 and the other being a ebcm fault. replaced abs valves and ebcm. only code to come back is 35 no rear speed signal. replaced vss sensor no luck checked all wiring seems ok at this time. on snap on scan tool rear sp...	View
	1998 Chevrolet Venture 3.4L Right Sliding Door VIN: 1GNDX03E0W Sliding door doesn't do anything - In diagnostics it beeps code 12 no problem. In mode 3 diagnostics it will not release latch or run motor. Passes all other diagnostics. Module just clicks when any switch is pushed. Has no voltage output to motor. We have tri...	View
	1998 Chevrolet C3500 Cheyenne 7.4L system voltage VIN: 1GBKC34J5W Truck came in with complaint of voltage guage dropping and battery light coming on when voltage gets low enough aprox 12.1 volts , this only occurs when being driven (at any speeds) at idle or when revved in shop will function fine ,we replaced alternator (max...	View
	1999 Chevrolet Monte Carlo LS 3.1L convertor VIN: 2G1WW12M4X torque convertor locks-up as soon as second gear engages, checked all engine data- ok, gear position switch, temp & press all look good, bucks violently in second. no debris in pan, fluid not burnt, suspect internal pressure leak, but removed pump, valve body,...	View
	2000 Chevrolet S10 2.2L Security System VIN: 1GCCS1942Y Hello Again Group, Vehicle was brought in from a used car dealer. Complain of no dome lights , blowing a 10 amp headlight fuse but a 25 amp was holding, no DRL and the Security Light on. Well when I got to it in a couple of days , the battery was dead , the Se...	View
	2001 Chevrolet Tracker LT 2.5L Automatic Headlamps VIN: 2CNBJ63491 Well, this is an odd one. When the vehicle was towed in the battery was dead and the cause was determined to be the headlamps were staying on all of the time. Cutting to the bottom line, only unplugging the ambiant light sensor on the dash would turn the light...	View
	1995 Geo Metro 1.0L oil consumption VIN: 2C1MR2262S Hi guys and gals - this metro came in for a burnt valve, which we repaired with new guides and exhaust valves, seals, etc. Ran excellant when done and turned over to customer. Several days later she complained that it was burning oil excessively and left it wi...	View
	1965 GMC 910 5.8L Poor Fuel Economy VIN: 0C91534807 not orginial engine, customer does not know what engine came out of. timing came in set at 30 degrees. is using to much gas. does any body know what the best timing would be at what rpm and degree?? thanks	View
	1994 Pontiac Grand Prix SE 3.1L Hesitation, Cuts out, Stall, MIL Lamp on VIN: 1G2WJ52MXR While driving car it will intermittantly cutout not allways stalling, just like the motor will immediatly go from 2000 rpm to 100 and then come back. seems that it usually will happen more on a cold engine yet we have also had it happen warm. we have many test... Trouble codes: 28 (Transmission Pressure switch circuit), 13 (HO2S Error)	View
	1997 Pontiac Firebird 3.8L MIL Lamp on VIN: 2G2FS22K2V customer brought car to us with check engine light on and found dtc po420 catalyst efficiency low bank 1 looked at all parameters and look good cleared the code and let customer drive the car a few weeks later the car came back with light on again same dtc so ... Trouble codes: P0420	View
	1999 Saturn SL2 1.9L Misfire, MIL Lamp on VIN: 1G8ZJ5270X Hello Everyone: I truly hope that one of my techs has helped someone in the past with a truly baffling problem!! Because, this Saturn is going to send me to Mars, Venus, and back!!! Like an idiot, I took on a SIMPLE engine swap from a local used car dealer o... Trouble codes: P0300 (Random cylinder misfire), P0302 (Cylinder misfire 2), P0303 (Cylinder misfire 3)	View
	2000 Saturn LS1 2.2L water pump VIN: 1G8JU52F1Y The noise is very obvious off idle. Listened with stethescope and was certain the noise was in the new pump. The new castings are slightly different, but Saturn parts assured me that that is not the problem. Also, the new pump has a metal impeller. The origina...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1994 Buick LeSabre Custom 3.8L battery light VIN: 1G4HP52L2R Thanks for all the help. The alternator was new. So i went straight to the pcm. After removing the board from the case, I found that I could make the battery light go out by flexing it. After replacing the pcm all was well. Thanks again.	8
	1997 Cadillac DeVille 4.6L Theft System VIN: 1G6KD54Y0V This Cadillac is fixed...some of the help received was right on...dissasembled the steering column and made sure the key cyl 2 white wires were O.K. gave 2 white wire loom wiggle test to make sure there was not a break in harness, Then as one tech suggested I ...	6
	1969 Chevrolet camaro 357CID Mechanical Well we have now run the engine long enough to break in the cam and the engine runs well. We didn't find any vacuum leaks on the manifold we checked the valve lash which was OK and adjusted the carburetor, also dialed in the total timing to 36* at 3000rpm. A l...	43
	1994 Chevrolet K3500 Cheyenne 6.5L Poor Idle Quality, Surge, Misfire VIN: 1GCHK33F2R This one is still pending, the customer informed us now that the engine is not original and maybe it requires different heads. We checed the feul pump and it works OK. will let you know if we find anything else.	6
	2000 Chevrolet Impala LS 3.8L pcm VIN: 2G1WH55K1Y Thanks to all 8 people who were kind enough to take time to help with my problem.The fix for the no compressor opperation was a new BCM.the problem I had was SI doc.was incorrect in one of its desciption of opperations, where it stated 12v signal was sent to t...	8
	2000 Chevrolet Suburban 1500 LT 5.3L compressor belt VIN: 3GNEC16T1Y I finally fixed this one thanks to several responses, but one in particular hit the nail on the head. Thanks John [...] for your very detailed description of problem. The compressor was the problem all along. I was unsure at first based on pressure readings a...	7
	2001 Chevrolet S10 4.3L system VIN: 1GCCS14W91 thanks for the help.what we ended up doing was taking the truck to the chevrolet dealer.They told us that it is the abs motor unit leaking internally.the dealer also said that there isn't a way to test for this problem,just plain experience is how they know.th...	7
	1991 GMC S15 Jimmy SLE 4.3L temp. gauge VIN: 1GKDT13Z1M Thanks to every one,after market sensor's were not calabrated right.Installed gm sensor and fixed.	4
	1996 GMC Jimmy SL 4.3L tcc solenoid VIN: 1GKCS13WXT I would like to thanks the technicians that offered me assistance. it was a weird one. ok first to the technicians that told me about the tsb. thank you I did this first which changed my amperage to my pc solenoid to the point where I could feel the trans goin...	8
	2000 Oldsmobile Alero GLS 3.4L Unknown VIN: 1G3NF52E0Y I replaced the 2 front wheel bearings and the noise went away. I would like to thank all the people who took their time to reply. A big thanks to Todd at the GM dealer who I spoke to on the phone. We fixed a vehicle for our #1 car lot customer. Couldn't have d...	9
	1993 Pontiac Grand Am SE 3.3L Cuts out VIN: 1G2NE54NBP Thanks for everyones help. The MAF sensor was extremely dirty, cleaning it did the trick. The timing issue was a false reading. Customer is happy and so am I. Thanks again. Steve [...]	6
	1996 Pontiac Bonneville SE 3.8L Stall VIN: 1G2HX52KXT Thanks for all the help.I have never seen a fuel pump act like this,but there is first time for every thing.fuel pressure would drop but come right back.replace pump and all is fine. thanks again,gary [...]	6
	1999 Pontiac Grand Am SE 3.4L Excessive Emissions, Poor Fuel Economy, MIL Lamp on VIN: 1G2NE52E2X thanks for all the replies. they all helped especially the info concerning the wiring colors etc. the problem turned out to be melted wiring and consequently open wires from the junction connector near the alternater to the pcm my tipoff was the recently repla...	5
	2002 Pontiac Grand Prix GT 3.8L ps pump VIN: 1G2WP52K02 thanks for the replies.cannot confirm cause of damage to pump.a couple guys mentioned the customer held steering at full lock for a long period of time.	5

(Also Available: All, Asian, Chrysler, European, Ford, GM.)