Diagnostic Test

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

1) FUEL LEVEL SENSOR VOLTAGE BELOW 0.4 OF A VOLT
NOTE: Diagnose any CAN - B or CAN -C Communication DTCs before continuing.

Ignition on, engine not running.

With the scan tool, read the Fuel Level Sensor voltage.

Is the Fuel Level Sensor voltage below 0.4 of a volt?

Yes
1. Go To step 2).
No
1. Refer to INTERMITTENT CONDITION .
2. Perform POWERTRAIN VERIFICATION TEST .
2) FUEL LEVEL SENSOR

Fig 1: Checking Fuel Level Sensor
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Fuel Pump Module harness connector.

Ignition on, engine not running.

Using a fused jumper wire, jump the (A109) Fused B+ circuit to the (N4) Fuel Level Sensor No.1 Signal circuit in the Fuel Pump Motor harness connector.

Did the Fuel gauge level change from empty to full?

Yes
1. Replace the Fuel Level Sensor.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 3).
3) (A109) FUSED B+ CIRCUIT

Fig 2: Checking Fused B(+) Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Using a 12-volt test light connected to ground, probe the (A109) Fused B+ circuit.

Does the test light illuminate brightly?

Yes
1. Go To step 4).
No
1. Repair the open or short to ground in the (A109) Fused B+ circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
4) (N4) FUEL LEVEL SIGNAL CIRCUIT SHORTED TO GROUND

Fig 3: Checking Fuel Level Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C1 Cluster harness connector.

Measure the resistance between ground and the (N4) Fuel Level Signal circuit in the Fuel Pump Module harness connector.

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (N4) Fuel Level Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
No
1. Go To step 5).
5) (N4) FUEL LEVEL SIGNAL CIRCUIT OPEN

Fig 4: Checking Fuel Level Signal Circuit
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (N4) Fuel Level Signal circuit from the Fuel Pump Module harness connector to the C1 Cluster harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Go To step 6).
No
1. Repair the open in the (N4) Fuel Level Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .
6) INSTRUMENT CLUSTER
NOTE: Before continuing, check the Instrument Cluster harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes
1. Repair as necessary.
2. Perform BODY VERIFICATION TEST - VER 1 .
No
1. Replace and program the Instrument Cluster per Service Information.
2. Perform BODY VERIFICATION TEST - VER 1 .