GM Automotive Technicians Technical Discussion and Fixes for Jan 11, 2008 - iATN (Members Only)

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Open Help Requests for GM

	Help Request	Answers
	1990 Buick Century Custom 3.3L no injector trigger VIN: 1G4AH54N1L There is no triggering action on the injector green and blue wires. They both have positive voltage all the time with key on. I have replaced the ECM. Did not help. I do not have correct wiring diagram, but I think they should lead to computer directly. Help p...	View
	1999 Buick Riviera 3.8L charging, srs, abs, acc VIN: 1G4GD2212X srs + abs lights come on intermittently, no codes. acc panel beeps and display goes crazy. data stream shows voltage in car spiking to 17+ volts when these problems occur. voltage regulator is internal. replace alternator, no help. checked all power and ground...	View
	1997 Cadillac DeVille 4.6L instrument cluster lights VIN: 11G6KF5491 Hey guys, This one is a headache. Car came in with intermitant instrument lights, then none at all. Had a MIL indication. Ran codes and got B1970 - Ext Lamp Power Fault. Tested battery, good. Tested headlight switch. All lights from switch work except the ins...	View
	1994 Chevrolet Corvette 5.7L No Start, MIL Lamp on VIN: 1G1YY22P2R want to know if opti spark should b loose when rotor is removed .. Trouble codes: 36 (low / hi resolution pulse in distributor), 42 (short in ign system)	View
	1995 Chevrolet Beretta 3.1L No Start, Stall VIN: 1G1LV15MXS You can start this car in mornnings, it may run 5 min, it may run 1/2 hour, engine just stalls, like you would shut the key off, but it looses no power. Sometimes you can just turn the key after it stalls & it will start right back up, then other times you can...	View
	2001 Chevrolet Silverado 2500 6.0L Misfire, MIL Lamp on VIN: 1GCGC24U11 This engine is bugging me. It came to me with flashing CEL code PO300. I checked misfire counter and #2 and #7 were counting misfires regularly at idle and PT. No. 7 is the worst by far. The engine has an audible miss at idle and throttle snap but plenty of po... Trouble codes: P0300	View
	2002 Chevrolet Tahoe LS 5.3L interior lights VIN: 1GNEK13Z82 Code B2618 in system. Can not clear code.Comes back. Can not perform any test with Tech 2 on this system while this code exist. The BCM is not grounding the Gy/Bk wire to the courtsy light relay. We can manually ground this wire to make them work. We replaced ...	View
	2004 Chevrolet Trailblazer LS 4.2L Axle seal left side VIN: 1GNDT13574 Ok Chevy guy's, this should be no big deal. I spoke to the dealer techs and they said it should come out with a couple of good blows.This did not move it at all. The removal instructions shows the axle being bolted in, which it is not on this model.I've tried ...	View
	2004 Chevrolet Express 2500 4.8L starter VIN: 1GBHG31V14 vehicle came in with an extremely noisy starter. we assumed (oops!) that this was a normal failing starter. replaced starter with a new one (not reman). once replaced we found that the starter was staying engaged (would disengage intermittantly)until the vehic...	View
	2004 Chevrolet Blazer LS 4.3L fuel spit back VIN: 1GNCT18X24 hello fellow iatn techs we have this 2004 chevy blazer that when filling up with gas causes the fuel pump at the gas station to click off unless its filled very slowly. we have visually inspected the evap and canister hoses for pinches or cracks but have seen ...	View
	2000 GMC Sierra 1500 SL 5.3L Poor Idle Quality, MIL Lamp on VIN: 2GTEC19T2Y Loyal cust came in awhile ago with same codes. We checked a few basics and sent him to the chev dealer up the road. We are a Ford dealership. They checked it, replace one injector and chemically cleaned the rest of the injectors. Now he has come back to us wit... Trouble codes: P0175 (rich bank 2), P0300 (randon misfire)	View
	2001 GMC Jimmy SLE 4.3L starter VIN: 1GKDT13W71 We have an '01 GMC Jimmy that the starter engages on its own only when vehicle is running and in park or neutral. When starter engages if you put vehicle in drive it stops. The starter relay is engergizing when it shouldn't. We pulled the relay and the problem...	View
	2002 GMC Sierra 1500 SL 4.8L fuel,temp guages, shift indicator, clock VIN: 1GTEC19V92 Customer originally came in for a shake in the vehicle & low coolant light on. Tech noted engine light on & pulled a 'u" code but it didnt make it on to the w/o. Cust. was back today with fuel & temp guage inop, abs light on, batt., low fuel, & security light ...	View
	2005 Hummer H2 6.0L front differential VIN: 5GRGN23U95 This one just came in with the front diff leaking out the vent tube. I've checked the forums and found nothing related. No service has ever been done to owners knowledge. Any help will be appreciated.	View
	1993 Oldsmobile 98 Touring 3.8L steering VIN: 1G3CV5313P Hi all. This car belongs to a very good customer. Recently he has had a problem with the steering getting very stiff when braking. Seems OK at idle, maybe a little stiffer with the brake on while idling. When driving at hiway speeds and you hit the brakes the ...	View
	1995 Oldsmobile Aurora 4.0L MIL Lamp on VIN: 1G3GR62C4S This car originally came in with the transmission banging in gear and no comm with pcm. Replaced PCM and corrected those two problems. The car ran fine after we installed pcm but the lite came on after 2 drive cycles with code 83 We replaced both crank sensors... Trouble codes: 83 (Loss of crank sensor 1 and 2)	View
	2001 Oldsmobile Silhouette Premiere 3.4L radiator VIN: 1GHDX23E61 Dear Fellow Techs: I know I am missing something easy and need a little help on this one. Another shop replaced water pump, thermostat and radiator. The vehicle runs 3/4 hot when at idle. When you accelerate the temperature goes down to normal. While the vehi...	View
	2000 Saturn LS 2.2L MIL Lamp on VIN: 1G8JS52F6Y check engine lite was on and the rear o2 heater circuit code was stored .changed sensor and road tested ok . customer came back checked again and rear o2 stays fixed for about two minutes and when it starts to switch the code triggers. power and ground circuit... Trouble codes: P0141	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	1998 Buick LeSabre Limited 3.8L actuator VIN: 1G4HR52K0W Solved by rerouting duct control system and using different switch.	3
	2000 Cadillac DeVille 4.6L Misfire, MIL Lamp on VIN: 1G6KD54Y4Y finally got it act up long enough to find the problem. had my quad 4 plug wire set up on the rear coil bank and like i said no spark on all 4 cylinders. had my dvom on the power wires to both sets of coils and when no spark was happening the voltage was droppi... Trouble codes: P0300.	12
	1991 Chevrolet Lumina Euro 3.1L No Start, injectors always on VIN: 2G1WN54T4M Unplugged ECM and noid light plugged into #6 injector stayed lit. Found ground side of injectors shorted to ground under upper intake manifold near power steering reservoir. Repaired shorted wiring and problem solved. Thanks to all who responded, Mike	15
	1993 Chevrolet C1500 Suburban 5.7L heater VIN: 1GNEC16KXP Good morning everyone. 2 of you hit the nail right on the head. Right after I posted this I had an idea and it turned out to be correct. I was getting no flow to the heater core. The connector on the intake manifold was plugged up. After I cleaned it the heate...	30
	1995 Chevrolet Monte Carlo Z34 3.4L noshift VIN: 2G1WX12X59 thanks tech for your help problem was bad ecm had water damage from leak at windshield runing down rear part of dash thanks fellow techs	5
	2000 Chevrolet Cavalier 2.2L cooling system VIN: 1G1JC5242Y Thank you all very much! All of you who said heater core problem were correct! I mistakenly assumed that since we were getting "OK" heat out of it, that it couldn't cause that big of a problem. Boy was I wrong! We temporarily bypassed the heater core and a...	13
	2001 Chevrolet Express 3500 5.7L starter VIN: 1GCHG35R01 GM stands for ground maintainance. G103 is the shared ground for these two, cleaning the ground at the back of the right cylinder head cured the problem. I just couldn't get my head around the power backfeed at the time. Thanks for all your replys, and big poi...	11
	2001 Chevrolet S10 2.2L no power on accel VIN: 1GCCS14591 This was a flex fuel vehicle. Turns out the flex fuel sensor thought the truck wasn't running on a petroleum based fuel. This in turn made it open up the injectors a bit causing the rich condition. Replacement of the sensor fixed the problem. Thank you for... Trouble codes: 172 (rich).	16
	2003 Hummer H2 6.0L Misfire VIN: 5GRGN23U83 thanks all the technician give me good advice, i did remove complete exhaust pipe at bank 2,and flash computer now the engine run good, it's catalytic converter plug up, but before i bring this message up, i also did remove oxygen sensor and exhaust flange to ... Trouble codes: P0300, P0101.	9
	1993 Oldsmobile Cutlass Ciera 3.3L Poor Idle Quality, Hesitation, Cuts out, Stall VIN: 1G3AG54N2P Thanks to everyone who helped with there info.Replaced Ecm and prom,all is well.Customer happy we are happy,hope all is well with all the Techs of IATN have a great weekend.	9
	1993 Pontiac Grand Am GT 3.3L ck guages & oil level VIN: 1G2NW14N8P The replies i received were mixed between a bad cluster and the oil level not being hooked up. It ended up being a bad cluster. after shorting the wires on the level sensor and having no change i installed a used cluster and things are back to working properly...	6
	1998 Saturn SW2 1.9L wipers VIN: 1G8ZK8274W Thank you to those who replied. The values I gave you were correct. I want to thank Chris from Identifix. He spend the extra time to test his own Saturn. he got the same numbers. The problem was the wiper motor module assembly. Thanks Again	2

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