GM Automotive Technicians Technical Discussion and Fixes for Feb 25, 2004

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Open Help Requests for GM

	Help Request	Answers
	1982 Buick Electra Park Avenue 5.0L MIL Lamp on VIN: 1G4AW69Y7C Hello one and all. Having trouble with the "Check Engine" light coming on after a few minutes of running when cold. Code 24 vehicle speed sensor fault code set. Diagnostic flow chart says that voltage should be at computer terminal H and if not then ECM is bad... Trouble codes: 24 (Vehicle Speed Sensor Problem)	View
	1998 Buick Regal LS 3.8L Unknown VIN: 2G4WBS2KOW This post is for another tech in our shop. I think we have a dandy here. Car has intermittent heater fan operation. Customer states when starting car and fan runs will run fine until car is shut off may not run upon next start up. We figured resistor, removed ...	View
	1988 Chevrolet V30 Cheyenne 7.4L front end VIN: 1GBJV34W8J This vehicle came to us for alignment. After minor adjustment, it was released to the customer. The customer returned to tell us the real reason for the alignment request. At about thirty mph, there is a violent shake in the front end. We replaced front shocks...	View
	1989 Chevrolet Beretta 2.8L Surge, Cuts out, Stall, Misfire VIN: 1G1LV14WXK This is Part 2 of my last help request. Part 1 was corrected by ECM replacement. As stated in the last help request, I originally had a missfire on cyl #5 with very bad miss on accelleration. I have replaced the faulty injector and all injector o-rings, all sp...	View
	1989 Chevrolet C2500 Cheyenne 5.0L coolong sys VIN: 1GCGC24K6K A reman engine from Mid-Atlantic was installed. The residule coolant that was deposited in the exhaust was given ample time to burn off. Final adjustments and short road tests were finalized leaving a 10 mile final road test befor releasing the vehicle to the ...	View
	1994 Chevrolet K2500 Cheyenne 5.7L Surge VIN: 2GCFK29K1R egr dudy cycle goes to 100% at light throttle and stays there. egr possition always reads o on scan tool. alldata does not describe how or where the ecu gets its information for the egr position other than the change in map senor voltage. perfomed the entire e...	View
	1996 Chevrolet p-30 school 5.7L Cuts out, Misfire, Poor Fuel Economy VIN: 1GBKP32R2T This one is eating my lunch and I am hungry.Bus came in with contaminated fuel tank with some kind of liquid,unidentified.Ran terrible under load,had lean exhaust indicated on right bank and left bank.I checked fuel pressure, well within specs.Replaced fuel fi...	View
	1997 Chevrolet Malibu 3.1L Mechanical VIN: 1GIND52M1V Thanks in advance. Customer brought this car in complaining of intermittant loud valve train noise and loss of power(customer thinks a lifter is to blame) Now i have it to diagnose and it is not making any noise. Scanned computer and no codes present history o...	View
	1998 Chevrolet Blazer 4.3L 4x4 Hi Folks: This is my daughters truck. I have road tested on more than one occasion and have been unable to duplicate the condition. It seems that this vehicle will change from 2WD to 4Hi or sometimes to 4Lo by itself. Sometimes it will happen while the truck i...	View
	1999 Chevrolet Tahoe 5.7L MIL Lamp on VIN: 1GNEK13ROX hello, I have this Tahoe that has intermitent problem. It will go into 4WD by its self and 4WD push buttons will come on. I went to go check it when it had its problem but when I got in to the truck I stepped on the brake I heard some clicking and than it was ... Trouble codes: P0724, U1026 (Class 2 ATC)	View
	1999 Chevrolet Blazer 4.3L Blend door VIN: 1GNDT13WW2 Hello fellow members. Got this Blazer that has poor heat and the blend door motor will not move .I tried doing the recalibration by taking out the radio/battery fuse and also tried disconnecting the battery over night. Borrowed a Tech 2 scanner and the pids di...	View
	2000 Chevrolet Astro 4.3L No Start VIN: 1GCDM19W2Y 1. Have spark to all cylinders 2. Have fuel pressure 55psi to 60psi 3. Has injector pulse on all injectors 4. Spray fuel in intake and engine still will not run 5. Tryed a new pcm. No change 6. Compression is good on all cylinders	View
	2001 Chevrolet Lumina 3.1L MIL Lamp on VIN: 2G1WL52J41 This car sets multiple O2 codes: P0131, P0133, and P1133. It has been in my shop a few times for this problem and is never acting up while it is here. The O2 has been replaced once recently and tests OK with a scope and propane. 1v max 100mV lean and less than...	View
	1991 Geo Tracker 1.6L 1-2 shift VIN: 2CNBJ18U0M This vehicle came in not shifting when cold. After it warms up, it shifts perfect. I replaced the v.b. and the modulator and also the governor. Vehicle is still not wanting to shift when cold. I can't see that anything in the clutch packs would cause this. Unl...	View
	1998 GMC Yukon SLE 5.7L Misfire, MIL Lamp on VIN: 1GKEK13R9W Vehicle has returned to shop numerous times for MIL lamp on, original misfires were obvious poppet nozzle issues as injector service cured problem temporarily. Repeated catalyst efficiency codes were eliminated after customer had converters replaced. After all... Trouble codes: P0300 (Random cylinder misfire)	View
	1999 GMC Jimmy SL 4.3L right brake lamp VIN: 1GKDT13W3X Goodmornig. This truck has left rear and third brake lamp operating but not the right.The signal is fine as is the ground and socket but no volatage when brake is applied.Could anyone tell me were the splice would be or send a wiring diagram. Thanks in advanc...	View
	1999 GMC Jimmy SL 4.3L Transfer case VIN: 1GKDT13W5X Hi Group, I have this jimmy that will not give me 4x4 in '4hi' or '4low', but works fine in 'auto 4x4'. The axle is engaging (I accessed the actuator and watched it) and the transfer case is shifting because when you run it on the hoist you get 4wd but as soo...	View
	1971 Oldsmobile cutlass 350CID direct clutch VIN: 342571M137 fellow techs, the question i have on this 350 turbo trans is when i removed the clutches and steels from the direct clutch there was 4 clutch disks and 5 steels the gm manual says there should be 4 of each . the manual im using doesnt say what clearance is acc...	View
	1992 Oldsmobile Achieva S 2.3L serpentine belt tension VIN: 1G3NL14A8N Customer complained of belt noise and voltage varying. Upon inspection of the belt we found it to be loose. The routing is correct. The alternator has been replaced but the pulley looks normal size. We checked the tensioner and it was "not" binding. The marks ...	View
	1999 Oldsmobile Silhouette Premiere 3.4L Raidator VIN: 1GHDX03E7X This van came in with water in oil and oil in raidator. The engine has water and antifreeze in the crank case and oil like substance in the raidator. Their are not large amounts of oil in the raidator, it looks like a milk shake substance but is not mixed with...	View
	1990 Pontiac Grand Am LE 2.5L speedometer VIN: 1G2NE54U5L Hi guys, thanks in advance. This Grand Am came in with a complaint of an inop speedometer, we verified that the speedo works, but it only registers very low in comparison to actual speed. Installed scan tool and determined no codes. Did find that the speedo an...	View
	1998 Pontiac Bonneville SSE 3.8L low boost VIN: 1G2HZ5214W we replace leaking valve cover gaskets and also replaced the plug wires.now the customer says the supercharger does not boost like it use to,unless at high rpm.he say's it drives like a 3800 w/o a supercharger.it takes a lot of throttle to bring the boost in.w...	View
	1998 Pontiac Grand Am GT 2.4L Excessive Emissions, Poor Idle Quality, Misfire, MIL Lamp on VIN: 1G2NW12T2W Hello to all, I have this grand am that came in for runs rough at times and Service engine light comes on at times. Came up with fuel system rich code. Pulled plugs they look like it is running slightly rich. Test drove and car feels sluggish off the line. Alm...	View

Fixes & Summaries for GM

	Fix/Summary	Answers
	2000 Buick Park Avenue 3.8L Interior VIN: 1G4CW52K8Y Customer chose not to pursue problem. Thanks to all who replied.	21
	2000 Buick LeSabre Custom 3.8L steering VIN: 1G4HP54K9Y This vehicle has not returned to our shop for repair. Either for the p/s hose replacement or the 'PCM' reflash for the transmission. Suggested to our human resource manager to let me personally force balance all the tires and verify that all are within specifi...	4
	1990 Cadillac Seville 4.5L No Start, Cuts out, Stall VIN: 1G6KS5335L thanks to all that help fix this car i really am greatfull to all what fixed this car was a remand computer with new prom i hope i don't see this car for awhile again thanks to all Trouble codes: 74 (mat interupted).	14
	1993 Cadillac DeVille 4.9L abs light on VIN: 1G6CD53B0P Well went to work this morning did more checks and measured resistance on the inlet circuit and found out it was above 10ohms,so replaced the the PMV assy. and all is well and could also clear the codes after.I would like to thank John [...] who suggested...	4
	1989 Chevrolet Beretta 2.8L No Start VIN: 1234368756 Thank you to all who took time to reply. The fix for this car was to replace the ECM. Had to purchase a Remn Cardone brand. The dealer said the ECM service # was no longer available in a reman. After completed repairs the car started right up. Still have #5 cy...	5
	1991 Chevrolet C1500 Cheyenne 5.7L Dash lights VIN: 2GCEC19K2M Hi Techs, I did not fix this truck yet because the customer had to take the vehicle and will bring it back at a later date. I checked and rechecked every ground I could find without finding a problem. I even ran a separate ground wire under the dash with no su...	12
	1992 Chevrolet Astro CL 4.3L Excessive Emissions VIN: 1GNDM19ZXN installed new ecm.problem solved.thanks for all of the help.	4
	1994 Chevrolet C1500 4.3L Surge, Cuts out VIN: NOTVALIDVI recieved several helpful things to try, thanx to all !!! Gerald [...] nailed it. Replaced the distributor and majic!!! this vehicle is fixed!!! wooooohoooo... waz sweatin that one thanx again guys	9
	1996 Chevrolet K1500 Suburban 5.7L Misfire, MIL Lamp on VIN: 1GKFK16R8T Well, it's great having you all. I did 3 fuel injection services so I could be sure the injectors are clean as they can get. I wanted to try to clean up as many as possible and then see which injectors were left causing the misfires. After the injection servic... Trouble codes: P0300 (random misfire).	10
	1996 Chevrolet Corsica 3.1L MIL Lamp on VIN: 1G1LD55MXT no purge flow=hose not fully seated,wouldnt roll out smoke under pressure...but oh well they're happy Trouble codes: 441 (no purge flow).	4
	1998 Chevrolet Corvette 5.7L Head light retractor motors VIN: 1G1YY2180K Thanks for the response the problem was that both retractor motors were striped on the inside and because there was no load the control unit could not switch them off.	5
	2002 Chevrolet Tahoe LS 5.3L FUEL GUAGE COOLANT TEMP GUAGE no communication w VIN: 1GNEK13Z42 i found a communication problem with the class 2 data at the splice pack. it was not allowing scan tool to communicate and making the dash go haywire. i cleaned and repositioned splice pack, and problem went away. thanks to everyone for their help.	3
	1992 Geo Tracker 1.6L fuel VIN: 2CNBE18UN6 Thanks to all who answered, got many replies saying the ecm was the problem and how to see if it was damaged. after removing the ecm i opened it up as instructed and found the board was corroded. replaced the ecm with a rebuilt unit and the vehicle started rig...	9
	2001 GMC Jimmy SLE 4.3L Poor Fuel Economy, MIL Lamp on VIN: 1GKDT13WX2 First a thanks to everyone who replied to my request for help. We found a loose vacumme connector to the Purge valve solonoid. The vacumme hose was not properly seated. We also found the vent solonoid at the rear crossmember. Pt # [...] Customer said he has... Trouble codes: P0440.	6
	1993 Oldsmobile Cutlass Supreme 3.1L Excessive Emissions, Poor Idle Quality, Hesitation, Surge VIN: 1G3WH14T1P I was not actually clearing ECM memory. Removal of the ECM fuse behind the glove compartment was not enough to clear ECM memory. I had to remove the fuse at R/F corner of engine compartment. Now vehicle can actually start from scratch, learning how to run. Rep...	7
	1998 Oldsmobile Silhouette Premiere 3.4L steering wheel, body VIN: 1GHDX03E2W thank you for all your help and support. had many replies within the first few hours. this vehicle costed me lots of time and money. we tried and tested everything that the replies had recommend. check everything over, check ball joints, tie rods, strut mounts...	18
	1999 Oldsmobile Silhouette GL 3.4L ignition VIN: 1GHDX03E0Y thanks to all who responded. the ignition switch was the problem with this silhouette. the e-mails provided good tech info that made the final diagnosis easy. the switch not only took care of the no start condition, but also cured some minor accessory problems...	6
	1991 Pontiac Firebird 3.1L Excessive Emissions, Poor Idle Quality, Poor Fuel Economy VIN: 1G2FS23T5M Hello everyone, this one is fixed by replacing all the injectors with the correct injectors. Kelly hit it right. One think I forgot to tell everyone was the o2 sensor readings. The readings were 980mv to 1000mv. The customer still says he had only one injector... Trouble codes: 45 (rich condition).	13
	1994 Pontiac Grand Prix SE 3.1L Radio VIN: 1G2WJ52M2S Well don´t know how to begin, didn´t fix it, but at least I know how to retrieve back up code. Back to the biginning, the radio can use or not a code, if you make the procedure to put a code when you first purchase the car every time power is removed (i.e. c...	7
	1999 Pontiac Grand Am SE 3.4L No Start, Cuts out, Stall VIN: 1G2NE52E4X The fix for the vehicle was to motorvac it. Apperently the body codes were caused by the Tech 2, advised to ignore them. recieved one reply from Marty [...] and I'd like to thank him Gerry Trouble codes: B2958 (Security system sensor data circuit high), B1365 (Ignition zero malfunction), U1040 (Loss of class 2 communication with ABS), U1255 (Class 2 communication malfunction).	1

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