Tag Archives: Computer

Car computer problems can be very hard to diagnose. Read our growing list of questions and answers to help you fix it yourself.


2004 Pontiac Grand Prix Catalytic Converter I/M Flag Not Ready

2004 Pontiac Grand Prix with a “2” motor will not go “Ready” with the catalytic converter test for I/M testing. I went in the service manual and did the testing for P0420 where you run the car for 1 minute in park then put in in drive while observing air/fuel mixture. The readings change from 14.7/1 to 12.3/1 then changes to 16.9 /1 as the…

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Chevy Impala Lights Clicking And Flashing After Battery Replaced

2002 CHEVROLET IMPALA -BATTERY WENT DEAD, REPLACED IT. NEXT DAY DOOR LOCKS LOCKING AND UNLOCKING ON THEIR OWN AND FUSE BOX CLICKING. I TESTED THE BATTERY AND ALTERNATOR AND BOTH ARE GOOD. DISCONNECTED BOTH CABLES FROM BATTERY, CLEANED REAL WELL HELD THEM TOGETHER 10/15 SECONDS. I WAS TOLD BY A LOCAL SHOP DOING THIS WOULD CLEAR AND RESET ELECTRICAL AS NEEDED. I HOOKED BATTERY BACK…

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2002 Chevrolet Malibu Transmission Codes and Blower Speed Problem

I had my 2002 Chevrolet Malibu serviced at non-Gm transmission shop which scanned the computer for codes. They found P0741 & P0730 which are TCC clutch related. I had them test drive the car to make sure it was not an intermittent problem which could be repaired other than the recommended re-flash of the PCM their service department suggested. They said the transmission wasn’t going into overdrive, so they flashed the computer. We…

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1998 Chevy Lumina Fans Quit Working

1998 Chevy Lumina question. Cooling fans quit working relays are good fuses are good fans work with direct power they don’t work with the temperature switch unplugged either. Could jump it at the PCM but don’t know where it is located. Answer: The PCM is located under a cover on the passenger side under the hood. You need a schematic to find out which wires…

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2006 Buick Rainier Won’t Shift And Speedometer Not Working

I have a 2006 Buick Rainier. Last night everything was fine. This morning when we were on our way to the store it would not shift and the speedometer stopped working working. What can i check to repair this problem. These 2 items would be related to one thing- the vehicle speed sensor(VSS). The VSS sends speed signal to the powertrain computer for speedometer operation,…

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1996 Toyota Corolla Has A Low Idle

I have a 1996 Toyota Corolla 1600 cc which started to rev very low on start up to the point that it would cut out. A code reader showed a coolant temperature sensor code so i replaced it . Now when I start the car is does rev higher but not as high as i think it should and remembering it doing. After a period…

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1997 Pontiac Grand Am ABS And Check Engine Light

My husband has a 1997 Pontiac Grand Am and the oil, ABS and check engine light came on, there is oil in the car and we just had maintenance work done on it a few months ago, spark plugs, fuel injector, fuel filter changes the whole works. It sounds rough now. what could it be. He put injector fluid in and the ABS and check…

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1999 Chevrolet Silverado Engine Light Code P0336

I have a 1999 Chevy Silverado 1500 series, 5.3. Code reads p0336 crankshaft sensor. Have replaced sensor 3 times and will not start. Put old sensor in and start. ProTech: When you replace the Crankshaft Sensor, you need to do a ‘crankshaft variation relearn’ with a scanner, or you will still have problems. How would i do that? You would either need a scanner like…

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2002 Buick Rendezvous Battery Has No Power and Won’t Start

I have a 2002 Buick Rendezvous. Yesterday it wouldn’t start, no power to anything. Charged the battery and it started and ran. This morning it started once but the second time same problem. Tried charging the battery and no luck. Checked battery it is good. I’ve been checking fuses and such, a couple times the overhead light will come on when I open the door,…

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2007 Chevy Equinox Freon Pressure Problem

2007 Chevy Equinox: HVAC A/C- 1) A/C on/off button not functioning, press to off and system still running as A/C, toggling/pressing repeatedly still no change 2) system ices up (suction hose) when on low fan but doesn’t on high fan? ProTech: Does the compressor come on right away when starting the truck with the A/C button off? A/C compressor does come on right away with…

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2004 Chevy Venture Accelerates On It’s Own

I have a 2004 Chevy venture van with a 3.4 that accelerates when it wants to. It happens when cold or hot, just starting or going down the road. I have changed the TPS and IAC and plugs for both of them. Found a bad vacuum line between Map and fuel pressure regulator and also one on the EGR and replaced both of them. I…

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Reduced Engine Power Warning And Check Engine Light

The reduced engine power warning message can come on your car or truck. Today’s vehicles are for the most part completely electronically controlled. From every button and switch on the dash down to the ‘fly-by-wire’ throttle control system. Back in the day, before these electronically controlled throttles, everything was cable actuated. You press the gas pedal, and a cable opens the carburetor or throttle body.…

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2003 Chevy Venture 5 Volt Reference Codes

I am getting code P1639 on my Chevy Venture van 2003. This is supposed to indicate a low 5 volt reference at the AC pressure sensor and the fuel tank pressure sensor. I have measured the voltage going to both sensors and get 5 volts. This is a gray wire in both cases. The AC has been working fine and I have no other codes.…

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