P0688-AUTO SHUTDOWN SENSE CIRCUIT LOW





For a complete wiring diagram Refer to Section 8W.



Possible Causes
(F342) ASD CONTROL OUTPUT CIRCUIT SHORTED TO VOLTAGE
(F342) ASD CONTROL OUTPUT CIRCUIT OPEN
(F342) ASD CONTROL OUTPUT CIRCUIT SHORTED TO GROUND
TIPM
PCM


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1. VERIFY ASD DTC

NOTE: Diagnose P0685 - Auto Shutdown Control Circuit first if it set along with this DTC.


Turn the ignition on.
With a scan tool, select View DTCs.

Is the DTC currently Active?

Yes


No

2. EXCESSIVE RESISTANCE IN THE (F342) ASD CONTROL OUTPUT CIRCUIT



Turn the ignition off.
Disconnect the C1 PCM harness connector.
Disconnect the C5 TIPM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.


Measure the resistance of the (F342) ASD Control Output circuit from the C5 TIPM harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes


No

3. EXCESSIVE RESISTANCE IN THE (F342) ASD CONTROL OUTPUT CIRCUIT



Disconnect the C3 PCM harness connector.
Measure the resistance of the (F342) ASD Control Output circuit from the C5 TIPM harness connector to the appropriate terminals of special tool #8815.

Is the resistance below 5.0 ohms at each terminal?

Yes


No

4. (F342) ASD CONTROL OUTPUT CIRCUIT SHORTED TO GROUND



Measure the resistance between ground and the (F342) ASD Control Output circuit at the C5 TIPM harness connector.

Is the resistance below 100 ohms?

Yes


No

5. (F342) ASD CONTROL OUTPUT CIRCUIT SHORTED TO VOLTAGE



Ignition on, engine not running.
Using a voltmeter measure the voltage on the (F342) ASD Control Output circuit in the C5 TIPM harness connector.

Is the voltage above 0 volts?

Yes


No

6. TIPM

Turn the ignition off.
Connect the C1 and C3 PCM harness connectors and the C5 TIPM harness connector.
Ignition on, engine not running.
Using the scan tool in the PCM, actuate the ASD.
With a 12-volt test light connected to ground, probe the (K51) ASD Control circuit at the C2 TIPM terminal connection.

Does the test light illuminate brightly and flash on an off during the actuation?

Yes


No

7. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.


Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes


No