Engine Controls - Diagnostic Methods - 6.0L Diesel: Wiring Ford Econoline E250

Harness Opens

The purpose is to check harness for open circuits

1. Key off.
2. DLC disconnected from any scan tools.
3. Disconnect the component from the harness.
4. Disconnect the appropriate PCM harness.
5. Using an ohmmeter, isolate the circuit in question from the harness pin to the component connector signal pin.
6. Reading should be less than 5 ohms.

Harness Shorts

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

1. Key off only.
2. DLC disconnected from any scan tools.
3. Disconnect the component from vehicle harness.
4. Using an ohmmeter, measure the resistance between the signal circuit and signal return circuit, power ground circuit, VREF circuit or vehicle power.
5. If reading is less than 5 ohms, then the two circuits are shorted.

The purpose is to check harness for open circuits.

1. Key off.
2. DLC disconnected from any scan tools.
3. Disconnect the component and PCM from vehicle harness.
4. Disconnect the appropriate PCM harness.
5. Using an ohmmeter, isolate the circuit in question from the harness pin to the component connector pin.
6. Reading should be less than 5 ohms.

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

1. Key off only.
2. DLC disconnected from any scan tools.
3. Disconnect the component and PCM from vehicle harness.
4. Using a digital multimeter, measure the resistance between the signal circuit and signal return circuit, power ground circuit, VREF circuit or vehicle power.
5. If reading is less than 5 ohms, then the two circuits may be shorted.