FE42 - Check DEF Circuit For Short to Power

- Key "OFF".

- Disconnect rear window defroster relay.

- Breakout Box installed, Powertrain Control Module (PCM) disconnected.

- Measure resistance between test pin 15 (test pin 23 for CD4E and Calif. M/T) and test pins 37/57 at breakout box.

- Is each resistance greater than 10,000 ohms?

Yes -- Remove breakout box. Reconnect all components. Refer to Heating and Air Conditioning to check for fault in rear window defroster switch and relay circuit.

No -- Service short circuit. Remove breakout box. Reconnect all components. Verify elimination of idle speed concern.