Codes p0463 and p0700

Fuel Gauge Troubleshooting

Fuel Gage
The IPC displays the fuel level as determined by the PCM. The IPC receives a class 2 message from the PCM indicating the fuel level percent. The fuel gage defaults to empty if:
• The PCM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of class 2 communications with the PCM.
When the fuel level is less than a pre-determined value, the CHECK GAGES indicator illuminates.
DTC P0462
The fuel level sensor changes resistance based on fuel level. The PCM monitors the signal circuit of the fuel level sensor in order to determine fuel level. When the fuel tank is full, the sensor resistance is high and the PCM senses a high signal voltage. When the fuel tank is empty, the sensor resistance is low and the PCM senses a low signal voltage. The PCM uses the signal circuit of the fuel level sensor in order to calculate the total remaining fuel (%) in the tank. The PCM sends the fuel level percent via the class 2 serial data circuit to the IPC in order to control the fuel gage. The fuel level information is also used for misfire and EVAP diagnostics
DTC P0463 (3.8L)

How to test fuel gauge tank sending unit P0463 GM

Check and or test fuel gauge sending unit and the gauge . Videos on youtube showing how to . Also i would have the vehicle checked for DTC's - diagnostic trouble codes . You may want to think about taking to a qualified repair shop .

Fuel Gage
The instrument panel cluster (IPC) displays the fuel level as determined by the engine control module (ECM). The IPC receives a serial data message from the BCM indicating the fuel level percent. The fuel gage defaults to empty if:
• The ECM detects a malfunction in the fuel level sensor circuit.
• The IPC detects a loss of serial data communications with the BCM.
• The BCM detects a loss of serial data communications with the ECM.

DTC P0461
The fuel level sender changes resistance based on fuel level. The powertrain control module (PCM) monitors the signal circuit of the fuel level sender in order to determine fuel level. When the fuel tank is full, the sender resistance is low and the PCM senses a low signal voltage. When the fuel tank is empty, the sender resistance is high and the PCM senses a high signal voltage. The PCM uses the signal circuit of the fuel level sender in order to calculate the total remaining fuel percent in the tank. The PCM sends the fuel level percent via the class 2 serial data circuit to the instrument cluster in order to control the fuel gage. The fuel level information is also used for misfire and evaporative emission (EVAP) diagnostics.

DTC P0462 Fuel Level Sensor Circuit Low Voltage
DTC P0463 Fuel Level Sensor Circuit High Voltage

sounds like you may have a bad fuel level sender problem. as for the check engine light coming on and storing a fault code that is a separate issue.

some fault codes stored in your car,
autocom can help you clear the fault codes and check your car.

take the sender unit out and check the float ,sounds like its full of petrol and not floating giving a reading of empty

That's got nothing to do w the O2 sensor. The float on the gas tank is a good start w the gauge issue .

It would be nice to know why the service engine light came on and is still on. An auto mechanic can read the code for you, or a dealer, or some parts stores will sell a device to read the code that caused the light to come on.

very well sounds like the sending unit in the tank. Try running some octane booster and fuel injection cleaner in tank of the truck to loosen any deposits on the float.

p0463 is a self diagnostic code that is for the fuel gage sending unit located inside the fuel tank if your fuel gage is reading empty just after you filled it then that verify's the code is correct you have a bad sending unit

Replace the fuel pump module (inside the fuel tank) it has 2 level sensors on it. The po463 code is an open condition on the high level sensor, one sensor reports to the ECM, other to your gas gauge on the dash.