Operation CHARM: Car repair manuals for everyone.

NB6 - Check IDM Circuit For Short to Ground



- Key "OFF".

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

- Ignition Control Module (ICM) (Pins 7-12) disconnected.

- Scan tool disconnected from Data Link Connector.

NOTE: During this check when the 4-wire Heated Oxygen Sensor (HO2S) is connected to the vehicle harness on Electronic Ignition (EI) vehicles, a short to SIG RTN (Pin 46) may be indicated in conjunction with an actual PWR GND short.

- Measure resistance between test pin 4 and test pins 16, 20, 40, 46 and 60 at the breakout box.

- Is each resistance above 10,000 ohm?

Yes -- Reconnect Scan Tool. Reconnect all components. Go to NB7. NB7 - Check ICM

No -- Remove breakout box. Service short to ground in Ignition Diagnostic Monitor (IDM) circuit. Reconnect all components. Clear continuous memory. Clearing Diagnostic Trouble Codes

Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)