Po463 fuel level sensor circuit voltage too high. how to fix

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

The P0463 code (Fuel Level Sensor Circuit High Voltage) means that your fuel guage circuit is open. To fix the fuel guage, the tank must come out to replace the sending unit. Personally I wouldn't worry about it too much. Use your trip guage and fill up after 200/250 miles. You'll never run out.

DTC P0463 - Fuel Level Sensor Circuit High Input
The fuel level sensor (sender) is located in the fuel tank usually integral to the fuel pump module. Usually they cannot be replaced without replacing the fuel pump module, though there are exceptions. There is a float attached to an arm that travels along a resistor which is grounded to the tank, frame or has a dedicated ground circuit. Voltage is supplied to the sender and the ground path changes according to fuel level. How much voltage depends on the system but 5 volts isn't uncommon.

As the fuel level changes, the float moves the arm and changes the resistance to ground which varies the voltage signal. This signal may travel to a fuel pump computer module or directly to the instrument cluster module. Depending on the system, the fuel pump computer module may only monitor the resistance to ground and then relay the fuel level information to the instrument panel. If the fuel level signal to the fuel pump module (or instrument cluster module or PCM (powertrain control module)) goes above 5 volts for a specific amount of time, then the module that is monitoring the fuel level circuit will record this fault code.

Symptoms of a P0463 DTC may include:
Mil (Malfunction indicator lamp) illumination
Fuel level gauge may fluctuate abnormally or read empty or full
Fuel light may illuminate and sound alarm

Potential causes of a P0463 code include:
The signal circuit to the fuel sender is open or shorted to B+ (Battery voltage)
The ground circuit is open, or ground path may have high resistance due to rust or missing ground ******** fuel tank
Damage to the fuel tank could cause problem in fuel level circuit
There's an open in the fuel lever sensor's resistor to ground
Possibly faulty instrument cluster
Less likely is the possibility that the PCM, BCM, or Fuel pump computer module has failed

Possible Solutions:
Fuel pump senders normally last the life of the fuel pump. So if you have this code present, do a visual inspection of the fuel tank and wiring harness. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Repair as needed. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. If not, repair the open or short in the wiring.

Doing a voltage drop test on the ground circuit can determine if there is a high resistance path in the ground circuit. You can perform this by using a voltmeter and connecting one lead to the battery ground post and the other to the fuel level sensor ground at the tank. Turn the key on (preferably the engine should be running). Ideally it should be 100 millivolts or less (.1 volts). Anything close to 1 volt indicates a current problem or a developing problem. Repair/clean the fuel level sensor ground as needed. It's not impossible that the instrument cluster has failed internally or on the printed circuit board (if applicable). These are very difficult for the layman to test. But if you have access to a wiring diagram you may be able to remove the cluster and see the damaged circuit if it's located on the printed circuit board, but otherwise you'll need a scan tool that will communicate with the instrument cluster.

A simple way to test the fuel level circuit is to provide a good ground to the fuel level sensor at the fuel tank connector. With the key on the fuel gauge should go to one extreme or the other. Removing the ground path completely should cause the gauge to do the opposite. If the gauge responds, you know the wiring that supplies voltage and ground to the fuel level sensor is good and that the instrument cluster is likely okay. The likely suspect would be the fuel level sensor itself. The fuel tank may need removal to gain access to the fuel pump module in the tank. A PCM or BCM (Body control module) failure isn't impossible but highly unlikely. Don't suspect this first.

Also, DTC P0462 - Fuel Level Sensor Circuit Low Input, same test to diagnosys.

DTC P0700 are transmission codes. Apparently something went wrong and the computer detected a difference in the position of the shift linkage and what gear the vehicle was in. You should be able to drive the vehicle during this period of time. The only thing you should be aware of is to make sure you don't feel any transmission slipage, otherwise you are fine until your appointment.

DTC P02610 - Control Module Long Term Memory Performance
This code is often set because the battery went dead and you tried to start it. There is a calibration update to correct this and it will not require a new ECM. See you dealer for the calibration update.

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my wifes truck has same problem, better off changing the whole fuel pump. the fuel level sensor is on the casing for the fuel pump. mine as well replace pump since you have to drop the tank anyway. before you order one, check on the drive side door jam to see what month you axiom was built. this is an important factor in ordering your fuel pump. sounds stupid i know but trust me. alot of parts for the axiom depend on the month.

DTC P0463 - Fuel gauge sender unit circuit high input
• The PCM monitors the fuel tank level and input voltage from the fuel gauge sender unit when the engine is running. If the input voltage is more than 2.5 V and fuel tank level is empty, the PCM determines that the fuel gauge sender unit circuit input voltage is high.

Diagnostic support note
• This is a continuous monitor (CCM).
• The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
• PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
• FREEZE FRAME DATA is available.
• The DTC is stored in the PCM memory.

Possible cause:
• Fuel gauge sender unit malfunction
• Instrument cluster malfunction
• PCM malfunction

Feel free to contact us if need additional details. Good luck.

P0463 - Fuel Level Sensor Circuit High Input
An excessively high voltage is sent from the sensor is sent to ECM.

The fuel level sensor is mounted in the fuel level sensor unit. The sensor detects a fuel level in the fuel tank and transmits a signal to the ECM or PCM.

It consists of two parts, one is mechanical float and the other side is variable resistor. Fuel level sensor output voltage changes depending on the movement of the fuel mechanical float.


Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)

Possible causes
- Fuel level sersor circuit harness or connectors is open or shorted
- Fuel level sensor may be faulty

Possible solution
Replaced fuel level sensor.

Hope helps (remember to rate this answer).

Fuel Level Indication System The fuel level indication system is a magnetic gauge system. It consists of a magnetic fuel gauge (9280) mounted in the instrument cluster (10849) and a sending unit located in the fuel tank (9002) with an instrument cluster gauge amplifier (10E849) in series between the two. No instrument voltage regulator is used with this system. Fuel Gauge
The magnetic gauge movement consists of three primary coils, one of which is wound at a 90-degree angle to the other two. The coils form a magnetic field which varies in direction according to the variable resistance of the sender unit which is connected between two of them. A primary magnet, to which a shaft and pointer are attached, rotates to align to this primary field, resulting in pointer position. The bobbin/coil assembly is pressed into a metal housing which has two holes for dial mounting. There is no adjustment, calibration or maintenance required for these gauges. The instrument cluster amplifier is calibrated to the fuel gauge. The instrument cluster amplifier and fuel gauge must be replaced as a system. Instrument Cluster Gauge Amplifier/Check Gauge Module
The instrument cluster gauge amplifier electrically averages fuel sender readings so the fuel gauge displays actual fuel level and not fluctuations due to sloshing in fuel tank. The instrument cluster gauge amplifier is a small printed circuit board which latches into a pocket on the back of the instrument cluster. The electrical connections for ignition, ground, input from fuel sender and output to fuel gauge are made through a spring-type connector on the instrument cluster gauge amplifier to the instrument cluster printed circuit (10K843) on the instrument cluster. There are no provisions for calibration or adjustment of the instrument cluster gauge amplifier.
Fuel Sending Unit
The fuel sending unit consists of a variable screened resistor made up of a ceramic substrate. It is controlled by the action of an attached float in the fuel tank. When the fuel level is low, resistance in the sending unit is low. When the fuel level is high, the resistance in the sending unit is high. As the float moves from empty to full, the resistance will gradually and continuously increase.

fuel level sensor is part of the fule pump assembly. code is telling you sensor is malfuctioning. do gauges work? if yes i would leave problem alone till you need a fuel pump

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.