Page 12 of 5267
P0685-AUTO SHUTDOWN RELAY CONTROL CIRCUIT
For a complete wiring diagramRefer to Section 8W.
Page 13 of 5267

When Monitored:
With ignition on. Battery voltage above 10 volts.
Set Condition:
The actual ASD state is not equal to the desired ASD state. One Trip Fault. Three good trips to turn off the
MIL.
Possible Causes
INTERNAL FUSED B+ CIRCUITS
(K51) ASD RELAY CONTROL CIRCUIT OPEN
(K51) ASD RELAY CONTROL CIRCUIT SHORTED TO GROUND
ASD RELAY
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ASD RELAY OPERATION
Ignition on, engine not running.
With a scan tool, actuate the ASD Relay.
Is the ASD Relay operating?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2
2.INTERNAL FUSED B+ CIRCUITS
Turn the ignition off.
Remove the ASD Relay from the IPM.
Using a 12-volt test light connected to ground, probe the Internal Fused
B+ circuits in the IPM.
Does the test light illuminate brightly?
Ye s>>
Go To 3
No>>
Repair the open or short to ground in the Internal Fused B+
circuits. Inspect and replace any open fuses.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
3.ASD RELAY
Measure the resistance of the ASD Relay Coil.
Is the resistance between 60 to 80 ohms?
Ye s>>
Go To 4
No>>
Replace the ASD Relay.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 14 of 5267
4.(K51) ASD RELAY CONTROL CIRCUIT OPEN
Disconnect the C3 PCM 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 (K51) ASD Relay Control circuit from the
IPM to the appropriate terminals of special tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 5
No>>
Repair the open in the (K51) ASD Relay Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
5.(K51) ASD RELAY CONTROL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (K51) ASD Relay Con-
trol circuit in the IPM.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K51) ASD Relay Control
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
Page 16 of 5267
P0688-AUTO SHUTDOWN RELAY SENSE CIRCUIT LOW
For a complete wiring diagramRefer to Section 8W.
Page 17 of 5267

When Monitored:
With ignition key on. Battery voltage greater than 10 volts.
Set Condition:
No voltage sensed at the PCM when the ASD relay is energized. One Trip Fault.Three good trips to turn off
the MIL.
Possible Causes
INTERNAL FUSED B+ CIRCUITS
(K342) ASD RELAY OUTPUT CIRCUIT OPEN
ASD RELAY
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 Relay Control Circuit first if it set along with this DTC.
With a scan tool, erase the DTC.
Attempt to start the engine. If the engine will not start, crank the engine for at least 15 seconds. It may be neces-
sary to repeat several times.
Does the DTC reset?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.ENGINE OPERATION
Attempt to start the engine.
Doestheenginestart?
Ye s>>
Go To 3
No>>
Go To 4
Page 18 of 5267

3.(K342) ASD RELAY OUTPUT CIRCUIT OPEN
Turn the ignition off.
Remove the ASD Relay.
Disconnect the C3 PCM 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 (K342) ASD Relay Output circuit from the
Relay connection to the appropriate terminals of special tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K342)ASD Relay Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
4.ASD RELAY
Turn the ignition off.
Install a substitute relay in place of the ASD Relay.
Ignition on, engine not running.
With a scan tool, erase DTCs.
Attempt to start the engine.
With a scan tool, read DTCs.
Does the DTC reset?
Ye s>>
Go To 5
No>>
Replace the ASD Relay.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 19 of 5267

5.INTERNAL FUSED B+ CIRCUITS
Turn the ignition off.
Using a 12-volt test light connected to ground, probe the Internal Fused
B+ circuits at the Relay connection.
Does the test light illuminate brightly?
Ye s>>
Go To 6
No>>
Repair the open or short to ground in the Internal Fused B+
circuits. Inspect the related fuse and repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
6.(K342) ASD RELAY OUTPUT CIRCUIT OPEN
Disconnect the C3 PCM 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 (K342) ASD Relay Output circuit from the
Relay connection to the appropriate terminals of special tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K342)ASD Relay Output circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 28 of 5267

Theory of Operation
The Park Neutral switch rationality test is enabled only for vehicles equipped with a 4/5 speed automatic transmis-
sion. This diagnostic checks if the park/neutral switch is incorrectly stuck in the neutral position during driving con-
ditions by comparing Vehicle Speed, Engine Speed, Throttle Position, andPressure Ratio to the fail thresholds and
by looking at the state of the Park/Neutral Switch. The stuck in drive condition is not explicitly checked as the starter
relay does not energize and therefore render the vehicle inoperable.
When Monitored:
Continuously with the transmission in Park, Neutral, or Drive and NOT in Limp-in mode.
Set Condition:
This code will set if the PCM detects an incorrect Park/Neutral switch state for a given mode of vehicle oper-
ation. One trip fault. Three good trips to turn off the MIL.
Possible Causes
TRS (T41) SENSE (P/N SENSE) CIRCUIT OPEN
TRS (T41) SENSE (P/N SENSE) CIRCUIT SHORTED TO GROUND
TRANSMISSION RANGE SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.P/N AND D/R NOT IN CORRECT POSITION
NOTE: Check the TCM for DTCs, if P0706 is set in the TCM diagnose the TCM code before continuing.
Ignition on, engine not running.
With the scan tool, read the Park/Neutral Position Switch input state.
While moving the gear selector through all gear positions (Park to 1 and back to Park), monitor the scan tool dis-
play.
Did the scan tool display show P/N and D/R in the correct gear positions?
Ye s>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 2