Engine Controls - Diagnostic Methods -- 6.0L Diesel: Wiring Ford Econoline E350 Super Duty

Harness Opens

The purpose is to check the harness for open circuits.

1. Key OFF.
2. Disconnect the component from the harness.
3. Disconnect the appropriate PCM harness.
4. Using an ohmmeter, isolate the circuit in question from the harness pin to the component connector signal pin.
5. The resistance value should be less than 5 ohms.

Harness Shorts

The purpose is to check the harness for short circuits (to ground or voltage).

1. Key OFF.
2. Disconnect the component from the vehicle harness.
3. Using an ohmmeter, measure the resistance between the signal circuit and signal return circuit, power ground circuit, VREF circuit, or vehicle power.
4. If the resistance value is less than 10,000 ohms, the 2 circuits are shorted.

The purpose is to check the harness for open circuits.

1. Key OFF.
2. Disconnect the component and the PCM from the vehicle harness.
3. Disconnect the appropriate PCM harness.
4. Using an ohmmeter, isolate the circuit in question from the harness pin to the component connector pin.
5. The resistance value should be less than 5 ohms.

The purpose is to check the harness for short circuits (to ground or voltage).

1. Key OFF.
2. Disconnect the component and the PCM from the vehicle harness.
3. Using a digital multimeter (DMM), measure the resistance between the signal circuit and signal return circuit, power ground circuit, VREF circuit, or vehicle power.
4. If the resistance value is less than 10,000 ohms, the 2 circuits may be shorted.