» » »

GMC Q&A

Ask Your Question

2003 GMC Sonoma Question: fuel sensor light stays on even after replacing fuel pump.

 

Question

speedy55, Bristol, TN, January 18, 2013, 13:52
 Rookie

Replace fuel pump with new GT280 connector Wiring is correct.What else could make the sensor light stay on?

1 Answer
Flag This
  • Answer #1

    gmc4me January 18, 2013, 15:19
    Profile_thumbnail
     Journeyman

    Did the pump come with a new fuel level sender? Was the light on before you replaced the fuel pump? What does the gas gauge read?

    Flag This
  • Reply

    speedy55, January 18, 2013, 15:50
     Rookie

    The light was on before we replaced the fuel pump .The gauge reads empty. The pump came full assembly. Truck starts and runs good, but light stays on.

    Flag This
  • Reply

    gmc4me, January 18, 2013, 17:13
    Profile_thumbnail
     Journeyman

    Assuming the sender is good I would either suspect a wiring issue with the 5 volt reference from the PCM, a wiring issue with the signal wire to the PCM, a problem within the IPC, or a wiring issue to the IPC. I suspect you put the tank back up or put the bed back on but checking for the problem at the fuel pump connector is best. You can check your 5 volt reference from the PCM at the fuel pump connectors purple wire. With connector disconnected you should have 5VDC with the key on. If you have 5VDC the PCM reference and wiring to pump connector is good on purple wire. With a paper clip you can check the reference signal to PCM by jumping the purple terminal to the signal wire with the key off. Im sorry but I do not know the color of the signal wire but I believe it's black. Then once jumpered turn the key on. Gas gauge should go to full. This will narrow down your problem to the signal wire, PCM issue with signal, or wiring to IPC. From there you will have to check resistance on wires for shortsor breaks.

    Reply
    Flag This