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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.
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)
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 .
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.
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
I didn't see an s15 in that model year, in my database?
If the speedometer works but the tach doesn't, I think something is wrong with instrument cluster?
GM has had a problem with fuel gage sending units. The sending units are not hard wired to instrument cluster, they send signal to pcm, the pcm sends serial data to instrument cluster, telling the cluster the gage settings.
It may be possible to use different size resistors in place of the fuel level sending unit, to see if fuel gage reacts properly to different resistors, if the gage reacts properly, then I think the problem is the fuel gage sending unit.
Maybe a problem with instrument cluster?
Usually the circuit works off resistance to ground. The sending unit in gas tank provides resistance to ground. The signal wire for fuel gage is a purple wire, if goes to fuel pump wiring connector. With key on, use digital multimeter, check for voltage. If no voltage, either problem with wiring circuit or instrument cluster. W/0 looking at instrument cluster, I don't know if you can replace gage itself w/o replacing instrument cluster?
If voltage on the purple wire, ground it, while a helper watches the gage, if the gage starts reacting, then check the grounds for fuel pump wiring connector, if that checks ok, suspect the fuel pump sending unit has a problem.
The oil gage and the fuel gage both use the same power and voltage control. so if the fuel gage is working the oil gage will work too. The sending unit is mounted on the motor and it gets hot and cold and has to put up with the acids that build up in the oil. this uit with a wire connected to it screws into the engine near the oil filter. The units that work the gage are quite expensive and many peaple just go on without one. I have a trooper and the gage does'nt work on it either and they cost alot and most stores don't have them.
Long Island City, NY
$116 at my store and they have to order it from the wearhouse.
Testing the fuel gage requires accessing the harness from the fuel pump and grounding the yellow / white wire with 160 ohms resistance this should cause the gage to read full, and with the circuit open you should have the gage reading empty. If the gage works in this order then the likely failure is the sending unit in the tank , and will require replacement.
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
A bad electric connector is possible. A bad tank sending unit can cause the same symptom. Usually the sending unit is a reostat mounted inside the tank.. it changes resistance depending on the float position, the resistance change causes a different voltage to the gauge or signal processor. The reostat may be a resistive plastic strip, as the float moves a contact pointer wipes the length of strip thus the change in resistance and voltage. Clear as mud?
Jason, as far as the fuel gage, try a couple of resisters at the wiring for fuel gage sending unit, in gas tank. It's two wires, use the resister inline between the two wires. One resister is for low fuel level, the other for high fuel, If the gage reacts properly to both resisters, the problem is the sending unit in the gas tank. You can try 40 ohm and 250 ohm resistors. I used to get resistors from radio shack, I don't know if they went bankrupt? The store in my community closed. Other places may have resisters? Just to add, the wire colors for sending unit/sensor are purple and black with white tracer.