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Chevy Silverado and GMC Sierra Electrical and Computer Questions

358 messages,  Last post on Dec 02, 2009 at 4:47 AM

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What is this discussion about? Chevrolet Silverado 1500, Chevrolet Silverado 2500, Chevrolet Silverado 3500, GMC Sierra 1500, GMC Sierra 2500, GMC Sierra 3500, Truck

#343 of 358 Re: 01 CHEV.1500 SERVICE ENGINE LIGHT [denham] by shaneo Oct 16, 2009 (8:53 pm)
Replying to: denham (Oct 16, 2009 10:39 am) here is your solution unplug the battery for 3mins just enough to reset your truck and pllug back the battery and turn your ignition back on a wham bye bye service engine light.....keep me posted Replies to this message: denham (Oct 26, 2009 8:15 am)
#344 of 358 Re: 01 CHEV.1500 SERVICE ENGINE LIGHT [denham] by obyone Oct 16, 2009 (11:33 pm)
Replying to: denham (Oct 16, 2009 10:39 am) P0440        DESCRIPTION The EVAP LARGE LEAK TEST is based on applying vacuum to the EVAP system and monitoring the rate of vacuum decay. The Powertrain Control Module (PCM) uses the input from the Fuel Tank Pressure (FTP) sensor in order to determine the rate of vacuum decay. At an appropriate time, the PCM turns the EVAP canister purge valve ON (open) and the EVAP canister vent valve ON (closed). This allows the engine to draw a vacuum on the system. At a calibrated time or vacuum level, the PCM turns the purge valve OFF (closed), and tests the system vacuum. If the system is unable to achieve the calibrated vacuum level, the PCM will set DTC P0440.   CONDITIONS FOR RUNNING THE DTC   •DTCs P0107. P0108, P0110, P0112, P0113, P0115, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1111, P1112, P1114, P1115, P1121 or P1122 are not set. •The system voltage is between 10-18 volts . •The startup (ECT) engine coolant temperature is between than 4-30°C (39-86°F) , but the start up ECT is not more than 8°C (14°F) more than the startup IAT temperature. •The startup (IAT) intake air temperature is between than 4-30°C (39-86°F) , but the start up IAT is not more than 3°C (7°F) more than the startup ECT temperature. •The fuel tank level is between 15-85 percent . •The Barometric Pressure (BARO) is more than 75 kPa . •The Vehicle Speed Sensor (VSS) is less than 75 mph . CONDITIONS FOR SETTING THE DTC The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.   ACTION TAKEN WHEN THE DTC SETS   •The control module illuminates the Malfunction Indicator Lamp (MIL) when the diagnostic runs and fails. •The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records. CONDITIONS FOR CLEARING THE MIL/DTC   •The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. •A current DTC, Last Test Failed, clears when the diagnostic runs and passes. •A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. •Use a scan tool in order to clear the MIL and the DTC. DIAGNOSTIC AIDS   •Use the EVAP pressure/purge diagnostic station in order to pressurize the EVAP system to aid in locating intermittent leaks. •Move all EVAP components while testing with the Ultrasonic Leak Detector. •A temporary blockage in the EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition. To repair a blockage in the EVAP system refer to Evaporative Emission (EVAP) System Cleaning. See: Emission Control Systems\Evaporative Emissions System\Service and Repair
#345 of 358 Re: 01 CHEV.1500 SERVICE ENGINE LIGHT [shaneo] by denham Oct 26, 2009 (8:15 am)
Replying to: shaneo (Oct 16, 2009 8:53 pm) Yes undo the battery will clear the code and the light will go out, but not fix the problem. The gas tank must build up pressure and most often it is the gas cap weak from use and you get the check engine light. This was my problem and I would say that anyone who has check engine light what any type auto they should first replace the gas cap as it could very well be the problem at little cost. Dennis
#346 of 358 turn signal issue by ahuff12 Oct 26, 2009 (2:27 pm)
03 1500 silverado..left turn signal will stop blinking when i put foot on brake pedal
#347 of 358 1999 gmc sierra by ray102 Nov 06, 2009 (9:00 pm)
my gadges go up and down and my batt. light comes on for a couple second and the gadges go crazy, rpm,speedomoder, oil,water temp, alt gadges go crazy and then quit working. does any body knows the problem please let me know. I change the alt. still not working. ray.
#348 of 358 Simple fix by azjas Nov 06, 2009 (10:33 pm)
It is the ignition harness causing you all the problems. Replace it -
#349 of 358 Electrical problem by silveradoz71 Nov 14, 2009 (10:02 pm)
#350 of 358 Electrical problem by silveradoz71 Nov 14, 2009 (10:02 pm)
We just bought a 2003 Silverado 1500 Z71, today we were leaving a store and all the lights on the instrument panel lit up (all of them at the same time) and the headlights dimmed for a second, then everthing was fine, went to another store and when I shut off the truck the electric door locks did not unlock, so I tried to start the truck and it was dead, nothing would come on, after a few attempts to start it, it just suddenly started, so we decided to go straight home, a few seconds after we pulled out the lights all came on again, Ive tried starting it a few times since with no problem, has anyone had a similar problem or any suggestions for me? i dont want to be left stranded somewhere.
#351 of 358 Re: Fuel Gauge/Fuel Pump/Electrical problem? [huff94] by tcbusa Nov 20, 2009 (6:56 am)
Replying to: huff94 (Aug 14, 2006 4:26 pm) huff, I had this problem with my 99' silverado 4.8,i replaced the fuel press. regulater & solved the problem.Got the part napa 84$,hope this is it.do it yourself job. tcbusa
#352 of 358 2003 Z71 self created electical problems by mark2003z71 Nov 23, 2009 (8:26 am)
Short story long, I had to jump my truck in the dark and like a big idiot I crossed the cables on the battery for about 30 seconds. Noticed the black cable on the positive post glowing. Quckly switched them and the truck started ok and made it home. I know, very stupid. Since then I have been getting a rough idle at stop signs where it feels like it might stall and the battery gage begins jumping from about 11 to 16 or so and it normally sits right at 14. I am also getting behavior where the radio will change stations or jump to new cd tracks if I hit one of the seat location buttons in the drivers side door and back to the original when I hit the other. The seat changes position to the correct position like normal. I have also had the radio turn off and reset itself back to 12:00. I have checked all of the fuses that I could find in the dash and in the box by the battery and they all seem good. Any thoughts on what I might have fried and how I can fix this?

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