P1431
Diagnostic Chart (Part 1 Of 2):
Diagnostic Chart (Part 2 Of 2):
Schematic:
CIRCUIT DESCRIPTION
The rear fuel level sensor 2, mounted in the rear fuel tank, measures fuel level changes within the rear fuel tank. The Fuel Level sensor 2 has a signal and a ground circuit.
When the fuel level is high the sensor signal voltage is high. When the fuel level is low the sensor signal voltage is low.
The PCM uses inputs from the fuel level sensor 1 and the fuel level sensor 2 in order to calculate the total fuel remaining in both fuel tanks. The system sends this information via the serial data to the IPC. This information displays on the fuel gauge.
This diagnostic tests for a stuck fuel level sensor 2 signal. If the PCM determines that the fuel level (rear tank) signal appears to be stuck based on a lack of signal variation expected during normal operation, this DTC sets.
CONDITIONS FOR RUNNING THE DTC
The engine is operating.
CONDITIONS FOR SETTING THE DTC
^ The secondary fuel tank is not empty.
^ More than 241 km (150 miles) have been accumulated.
^ The PCM does not detect that the fuel level in the rear fuel tank moved by at least 3.0 liters (0.80 gallons).
OR
^ The secondary fuel tank is not empty.
^ The primary fuel tank is not full.
^ Engine operating more than 60 minutes.
^ The primary tank does not achieve the top of its range. Observe, after operating the engine for more than 60 minutes the fuel in the rear fuel tank will transfer to the front fuel tank.
OR
^ The secondary fuel tank is empty.
^ The primary fuel tank is full.
^ The fuel level in both fuel tanks does not change after traveling more than 284 km (200 miles). Observe, if the secondary fuel tank is empty, the primary fuel level should decrease after 284 km (200 miles).
ACTION TAKEN WHEN THE DTC SETS
^ The PCM stores the DTC information into memory when the diagnostic runs and fails.
^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
^ The vehicle fuel gauge displays empty.
^ The Check Gauge lamp illuminates.
^ The Driver Information Center displays a message.
CONDITIONS FOR CLEARING THE DTC
^ A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
^ A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
^ Use a scan tool in order to clear the DTC.
DIAGNOSTIC AIDS
IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the module. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM.
^ For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter kit J 35616-A. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams.
Depending on the current fuel level, it may be difficult to locate a malfunctioning sending unit. The malfunction may only occur when the fuel level is full or near empty. The fuel sending unit may need to be removed for further diagnosis. A fuel level sensor that has an intermittent condition causes this DTC to set. Remove the fuel level sensor. Refer to Fuel Sender Assembly Replacement in order to test the resistance of the sensor. The resistance of the sensor should change from 40 to 250 ohms. Replace the sensor if the resistance did not change or was out of range.
The following occurs with this DTC set:
^ The vehicle fuel gauge displays empty.
^ The Check Gauge lamp illuminates.
^ The Driver Information Center (DTC) displays a message.
^ The voltages in the Fuel Level Conversion Table are approximate values. Use this table to aid in diagnosis.
^ If the fuel level sensor is operating OK, test the operation of the Balance Pump.
^ For an intermittent condition, refer to Testing for Intermittent and Poor Connections.
TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. Use DTC P0461 table if DTCs P0461 and P1431 set.
3. This step determines if a circuit condition is causing the fuel level signal to be at a fixed value.
4. This step determines if a circuit condition is causing the fuel level signal to be at a fixed value.
5. This step determines if fuel is being delivered to the right fuel tank jet pump.
The fuel pump will run for 2 seconds each time it is commanded ON with the scan tool. The fuel pump must be enabled several times to achieve the time specified in the diagnostic table.
6. This step determines if fuel is being transferred to the left fuel tank. The fuel pump runs for 2 seconds each time it is commanded ON with the scan tool. The fuel pump must be enabled several times to achieve the time specified in the diagnostic table.
7. Foreign material in the fuel tank may cause the sensor to stick. Inspect the strainer for interfering with the float arm. A stuck sensor may not be apparent when the sensor is removed from the fuel tank. The following may have caused the DTCs to set:
^ The fuel tanks over filled.
^ Fuel level that is almost empty and then re-fueled with only a couple gallons.
^ The Fuel Level sender un-stuck while re-fueling.
^ The Fuel Level sender un-stuck on rough road or going around a corner.
16. The PCM will not reset the mileage for this diagnostic if the fuel tanks are re-fueled to the same level as before the repair was made. Perform the following procedure in order to re-fuel the vehicle after replacing a sending unit or fuel tank.
1. Add 25 percent of the fuel that you removed before the repair.
2. Start and idle the engine for 5 minutes.
3. Turn OFF the engine.
4. Add the remainder of the fuel.