JCB P0685: ECM / PCM Power Relay Control Circuit Open

The fault code indicates an open circuit in the control circuit for the ECM / PCM power relay. This may prevent the relay from functioning properly, potentially affecting the operation of the engine control system.

1. 1

   The wiring and connections associated with the ECM / PCM power relay control circuit

2. 2

   The ECM / PCM power relay itself for signs of damage or failure

3. 3

   Fuses related to the ECM / PCM power relay control circuit

1. 1

   Inspect

   Inspect the wiring and connections for the ECM / PCM power relay control circuit for any signs of damage, corrosion, or disconnection.

2. 2

   Test

   Test the ECM / PCM power relay for proper operation using a multimeter or diagnostic tool.

3. 3

   Check

   Check the fuses related to the ECM / PCM power relay control circuit to ensure they are intact and functioning.