P0460
Fuel Gauge Unit Circuit:
Connectors:
CIRCUIT OPERATION
- The fuel gauge drive signal is input in PCM (terminal 60).
TECHNICAL DESCRIPTION
- Branch the drive signal from the fuel gauge circuit, and input it into PCM.
- The PCM detects the amount of fuel left in the fuel tank with this signal, and also controls the fuel level warning light.
DTC SET CONDITIONS
Check Area
- Engine coolant temperature is higher than 30° C (86° F).
- Barometric pressure is higher than 76 kPa (11 psi).
- Intake air temperature is higher than -10° C (14° F).
- Fuel gauge unit output voltage is 1.46 - 4.20 volts.
- After detecting the power steering pressure switch "ON" signal.
Judgment Criteria
- The variation width of the fuel gauge unit output voltage is 0.039 volt or less.
TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Fuel gauge unit failed.
- Open or shorted fuel gauge unit circuit, or loose connector.
- PCM failed.
DIAGNOSIS
Required Special Tool:
MB991502: Scan Tool (MUT-II)
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 1. Using scan tool MB991502, check data list item 4B: Fuel Level Sensor.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Set scan tool MB991502 to the data list mode for item 4B, Fuel Level Sensor.
- 100 - 3,600 mV (when the fuel gauge is near "FULL")
- 2,700 - 6,200 mV (when the fuel gauge is near "EMPTY")
4. Turn the ignition switch to "LOCK" (OFF) position.
If within specifications, this malfunction is intermittent. Refer to vehicle level Testing and Inspection.
If within specifications, go to Step 2.
STEP 2. Check the circuit voltage at fuel temperature sensor connector E-30.
1. Do not disconnect the fuel temperature sensor connector E-30.
2. Turn the ignition switch to "ON" position.
3 Measure the voltage between terminal 2 and ground by backprobing.
Standard value:
0.1 - 3.6 V (when the fuel gauge is near "FULL")
2.7 - 6.2 V (when the fuel gauge is near "EMPTY")
4. Turn the ignition switch to "LOCK" (OFF) position.
If within specifications, go to Step 3.
If not within specifications, go to Step 6.
STEP 3. Check the circuit voltage at PCM connector C-90.
1. Do not disconnect the PCM connector C-90.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 60 and ground by backprobing.
Standard value:
0.1 - 3.6 V (when the fuel gauge is near "FULL")
2.7 - 6.2 V (when the fuel gauge is near "EMPTY")
4. Turn the ignition switch to "Lock" (OFF) position. If within specifications, go to Step 4.
If not within specifications, check connector E-30, C-90 and repair or replace as required.
Refer to vehicle level Testing and Inspection.
Then go to Step 13.
STEP 4. Check the harness wire between fuel level sensor connector E-30 and PCM connector C-90.
NOTE: Check the wire after checking Intermediate connectors E-44, C-85. If Intermediate connectors E-44, C-85 is damaged, repair or replace them.
Refer to vehicle level Testing and Inspection.
Then go to Step 13.
If wire between fuel level sensor connector E-30 and PCM connector C-90 is not damaged, check connector C-90 and repair or replace as required.
Refer to vehicle level Testing and Inspection.
If connector C-90 is in good condition, go to Step 5. If wire between fuel level sensor connector E-30 and PCM connector C-90 is damaged, repair it.
Then go to Step 13.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
STEP 5. Using scan tool MB991502, check data list item 4B: Fuel Level Sensor.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Set scan tool MB991502 to the data list mode for item 4B, Fuel Level Sensor.
- 100 - 3,600 mV (when the fuel gauge is near "FULL")
- 2,700 - 6,200 mV (when the fuel gauge is near "EMPTY")
4. Turn the ignition switch to "LOCK" (OFF) position.
If within specifications, this malfunction is intermittent. Refer to vehicle level Testing and Inspection.
If not within specifications, replace the PCM. Then go to Step 13.
STEP 6. Check the ground circuit voltage at fuel level sensor connector E-30.
1. Do not disconnect the fuel level sensor connector E-30.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 3 and ground by backprobing.
- Voltage should be 0.5 volts or less.
4. Turn the ignition switch to "LOCK" (OFF) position.
If 0.5 volts or less, go to Step 7.
If more than 0.5 volts, check connector E-30, E-44 and repair or replace as required.
Refer to vehicle level Testing and Inspection.
If connector E-30, E-44 is in good condition, check the harness between fuel level sensor connector E-30 and ground for open circuit or damage. Then repair if necessary. Then go to Step 13.
STEP 7. Check the fuel level sensor connector E-30 for damage.
If the harness connector E-30 is in good condition, go to step 8.
If the harness connector E-30 is damaged, repair or replace it.
Refer to vehicle level Testing and Inspection.
Then go to Step 13.
STEP 8. Check the fuel level sensor.
Refer to Combination Meter.
If correct, go to Step 9.
If incorrect, replace fuel gauge unit.
Then go to Step 13.
STEP 9. Check the 12-volt voltage at fuel level sensor connector E-30.
1. Disconnect the combination meter connector C-02 (to interrupt current flow from the combination meter).
2. Disconnect the fuel level sensor connector E-30 and measure at the harness side.
3. Turn the ignition switch to "ON" position.
4. Measure the voltage between terminal 2 and ground.
- Voltage should be battery positive voltage.
5. Turn the ignition switch to "LOCK' (OFF) position.
If within specifications, check the harness between fuel level sensor connector E-30 and PCM connector C-90 for damage.
Then repair if necessary.
Then go to Step 13.
If not within specifications, go to Step 10.
STEP 10. Check the harness wire between fuel level sensor connector E-30 and PCM connector C-90 for open circuit.
NOTE: Check the wire after checking Intermediate connectors E-44, C-85. Intermediate connectors E-44, C-85 is damaged, repair or replace them.
Refer to vehicle level Testing and Inspection.
Then go to Step 13.
If wire between fuel level sensor connector E-30 and PCM connector C-90 is not damaged, go to Step 11.
If wire between fuel level sensor connector E-30 and PCM connector C-90 is damaged, check connector E-30, C-90 and repair or replace as required.
Refer to vehicle level Testing and Inspection.
If connector E-30, C-90 is in good condition, repair the wire between fuel temperature sensor connector E-30 and PCM connector C-90.
Then go to Step 13.
STEP 11. Check the harness wire between fuel level sensor connector E-30 and PCM connector C-90 for short circuit to ground.
1. Disconnect the combination meter connector C-02 (to avoid the effect of the line branched to the combination meter).
2. Disconnect the fuel level sensor connector E-30 and PCM connector C-90.
3. Check the continuity between fuel level sensor connector E-30 harness side terminal 2 and the ground.
- There should be open circuit. If open circuit, go to Step 12.
If there is continuity, check connector C-90, C-02 and repair or replace as required.
Refer to vehicle level Testing and Inspection.
If connector C-90, C-02 is in good condition, check the harness between fuel level sensor connector E-30 and PCM connector C-90 for short circuit to ground, and check the harness between fuel level sensor connector E-30 and combination meter connector C-02 for short circuit to ground. Then repair if necessary.
Then go to Step 13.
STEP 12. Check PCM connector C-90 for damage.
If harness connector C-90 is in good condition, replace the PCM.
Then go to Step 13.
If harness connector C-90 is damaged, repair or replace it.
Refer to vehicle level Testing and Inspection.
Then go to Step 13.
STEP 13. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Read the diagnostic trouble code, and confirm that a diagnostic trouble code P0460 does not reset.