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barncleaner
New User
Jun 30, 2008, 5:18 AM
Post #1 of 3
(8171 views)
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Malibu fuel guage
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I have a 1997 malibu that whenever I turn the ignition on the fuel guage needle goes past full to the lower peg of the guage and stays there when the car runs. I it is a problem with the sender, but not sure where to start. Has me baffled. Any help where to start and suggestions would be greatly appreciated. Thanks.
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DanD
Veteran
/ Moderator
Jul 2, 2008, 5:00 AM
Post #2 of 3
(8160 views)
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Re: Malibu fuel guage
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A simple fuel gauge circuit isn’t all that simple anymore and to properly diagnose it you should have a scan tool to read the values being sent too and from the different modules.
The fuel tank module is sent a reference voltage from the body control module (BCM). The fuel tank module sends a varying return voltage back to the BCM depending on fuel level.
From there the BCM sends out information via serial data (computer language) to the power train module (PCM) and the instrument cluster. The PCM uses this information for testing of the evaporative emissions system; the PCM will only test that system if the fuel level is between ¼ & ¾ of fuel in the tank.
The instrument cluster; when it receives this information moves the fuel gauge needle to the appropriate position on the gauge.
Like I said this simple circuit is now not all that simple; shorting or jumpering different wires, like we use to do, could end up burning out a module, in some cases.
But if you’re willing to try; there is a chance of confirming whether the problem is in the tank or not.
I will not take any responsibility for this but if you were to unplug the tank unit back at the tank and jumper the black/white wire terminal D and the purple wire terminal A of the car’s harness. Turn the ignition on to the run position and check what the gauge is doing. Don’t leave the keys on any longer then necessary. With these two wires connected the gauge should go down to the empty mark.
This shouldn’t do any harm to the system IF THE PROBLEM IS IN THE TANK. If the problem is elsewhere you could do some damage?
Your choice to try.
Dan.
Canadian "EH"
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flgmtech1
User
Jul 4, 2008, 1:42 PM
Post #3 of 3
(8147 views)
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Re: Malibu fuel guage
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Fuel gauge does not operate properly. - Perform an instrument cluster WOW in SPECIAL FUNCTIONS.
- Replace the cluster if the gauge does not sweep full range.
- Use a Scan Tool in order to read the DTC's.
Refer to DTC P0462 Fuel Level Sensor Circuit Low Voltage and DTC P0463 Fuel Level Sensor Circuit High Voltage or any Loss of SPI DTCs. DTC P0462 Fuel Level Sensor Circuit Low Voltage
DTC P0463 Fuel Level Sensor Circuit High Voltage
From you post, it appears that you need to use a Tech 2 to sweep the gauges ubder special functions in the Body section of the Tech 2, this will prove the IPC response, this can identfiy iussues in the cluster versus the Tank, however the scan tool can also tell you if you have one of the two codes above, and if so. then you need to use a DVOM and find out if the circuits shown above are open or shorted to ground or shorted to voltage. The key is to know if there are DTC;s and if not then the most common problems we see daily are problems with the cluster themselves. This typically happens when someone disconnects the battery with the key in the on position. #03-08-49-015: Info - Fuel Gauge Needle Reset Procedure After Battery Disconnect/Replacement with Key in ON Position - (Oct 7, 2003)
 Subject: Fuel Gauge Needle Reset Procedure After Battery Disconnect/Replacement with Key in "ON" Position Models: 1997-1999 Chevrolet Malibu 1997-1999 Oldsmobile Cutlass
After a battery disconnect or replacement, the fuel gauge may peg past the "full" mark if the disconnect/replacement occurred while the ignition key was in the "ON" position. If the key is left in the "ON" position when the battery is reconnected, the voltage surge may cause the fuel gauge needle to swing past the full mark all the way around below the empty mark.
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