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)
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
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)
When Monitored:
Ignition on.
Set Condition:
When the PCM recognizes Brake Switch No.2 voltage is not equal to the applied value at the PCM when
Brake Switch No.1 is applied. This could be a normal condition. If this condition is seen repeatedly by the PCM
the fault is set. Cruise will not work for the rest of the key cycle.
Possible Causes
(V30)FUSEDIGNITIONSWITCHOUTPUTCIRCUIT
(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT OPEN
(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO GROUND
(B29) BRAKE SWITCH NO.1 SIGNAL CIRCUIT OPEN
STOP LAMP SWITCH
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Make sure the Stop Lamp Switch is adjusted properly before continuing.
NOTE: Make sure the Stop Lamp Switch is properly wired, such as (B29) Brake Switch No.1 and (L50) Brake
Lamp Switch Output are not switched at the harness connector.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
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.(V30) FUSED IGNITION SWITCH OUTPUT CIRCUIT
Turn the ignition off.
Disconnect the Stop Lamp Switch harness connector.
Using a 12-volt test light connected to ground, probe the (V30) Fused
Ignition Switch Output circuit in the Stop Lamp Switch harness connec-
tor.
Does the test light illuminate brightly?
Ye s>>
Go To 3
No>>
Repair the open or short to ground in the (V30) Fused Igni-
tion Switch Output circuit. Inspect the related fuse and
repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
3.STOP LAMP SWITCH
Turn the ignition off.
Measure the resistance between the (V30) Fused Ignition Switch circuit
terminal and the (V32) Brake SwitchNo.2 Signal terminal in the Stop
Lamp Switch.
Measure the resistance between the (Z429) Ground circuit terminal and
the (B29) Brake Switch No.1 Signal terminal in the Stop Lamp Switch.
Apply and release the Stop Lamp Switch while monitoring the ohmme-
ter.
Does the resistance change from below 5.0 ohms to open cir-
cuit for each circuit check?
Ye s>>
Go To 4
No>>
Replace the Stop Lamp Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
4.(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
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 voltage on the (V32) Brake Switch No.2 Signal circuit in
the Stop Lamp Switch harness connector.
Ignition on, engine not running.
Is the voltage above 0 volts?
Ye s>>
Repair the short to battery voltage in the (V32) Brake
Switch No.2 Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
When Monitored:
Ignition on. In plant mode only.
Set Condition:
PCM recognizes the Brake Pedal couldnot electrically indicate the applied (On) position with both switch
inputs. One trip fault.
Possible Causes
(B29) BRAKE SWITCH NO.1 SIGNAL CIRCUIT OPEN
(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT OPEN
STOP LAMP SWITCH
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Make sure the Stop Lamp Switch is adjusted properly before continuing.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
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.STOP LAMP SWITCH OPERATION
Turn the ignition off.
Disconnect the Stop Lamp Switch harness connector.
Measure the resistance between the (Z429) Ground circuit terminal and the(B29) Brake Switch No.1 Signal terminal
in the Stop Lamp Switch.
Apply and release the brake pedal while monitoring the ohmmeter.
Does the resistance change from below 5.0 ohms to open circuit when pressingandreleasingthe
brake pedal switch?
Ye s>>
Go To 3
No>>
Replace the Stop Lamp Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.STOP LAMP SWITCH OPERATION
Measure the resistance between the (V30) Fused Ignition Switch Output terminal and the (V32) Brake Switch No.2
Signal circuit terminal in the Stop Lamp Switch.
Apply and release the brake pedal while monitoring the ohmmeter.
Does the resistance change from below 5.0 ohms to open circuit when pressingandreleasingtheStop
Lamp switch?
Ye s>>
Go To 4
No>>
Replace the Stop Lamp Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
When Monitored:
Ignition on, In plant mode passed the Applied test.
Set Condition:
PCM recognizes the Brake Pedal could not electronically indicate the released (Off) position with both
switches. If P1572 sets, P1573 will also set. One trip fault.
Possible Causes
(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(B29) BRAKE SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO GROUND
STOP LAMP SWITCH
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Make sure the Stop Lamp Switch is adjusted properly before continuing.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
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.STOP LAMP SWITCH OPERATION
Turn the ignition off.
Disconnect the Stop Lamp Switch harness connectors.
Measure the resistance between the (Z429) Ground circuit terminal and the(B29) Brake Switch No.1 Signal terminal
in the Stop Lamp Switch.
Apply and release the brake pedal while monitoring the ohmmeter.
Does the resistance change from below 5.0 ohms to an open circuit when pressing and releasing the
brake switch?
Ye s>>
Go To 3
No>>
Replace the Stop Lamp Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3.STOP LAMP SWITCH OPERATION
Measure the resistance between the (V30) Fused Ignition Switch Output circuit terminal and the (V32) Brake Switch
No.2 Signal terminal in the Stop Lamp Switch.
Apply and release the brake pedal while monitoring the ohmmeter.
Does the resistance change from below 5.0 ohms to an open circuit when pressing and releasing the
Stop Lamp switch?
Ye s>>
Go To 4
No>>
Replace the Stop Lamp Switch.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
P1603-PCM INTERNAL DUAL-PORT RAM COMMUNICATION FAILURE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition on and battery voltage greater than 10 volts.
Set Condition:
Internal PCM failure detected. One Trip Fault. Three good trips to turn offthe MIL.
Possible Causes
PCM FUSED IGNITION SWITCH CIRCUIT
PCM INTERNAL
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.PCM IGNITION CIRCUITS
Turn the ignition off.
Disconnect the C1 PCM harness connector.
Ignition on, engine not running.
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.
With a 12-volt test light connected to ground and with special tool
#8815 installed, probe the (F202), (F1), and (T751) Fused Ignition
Switch circuits.
Perform the above check with the Ignition key in the off lock position,
Ignition on, engine not running position, and during cranking.
Wiggle the related wire harness while probing the special tool with the
test light to try to interrupt the circuit.
Does the test light illuminate brightly?
Ye s>>
Go To 2
No>>
Repair the open or excessive resistance in the (F202), (F1), and (T751) Fused Ignition Switch (Offf,
Run, Start) circuits. Inspect the related fuse, if the fuse is open check the circuits for a short to ground.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.PCM
The Powertrain Control Module is reporting internal errors.
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?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Replace and program the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)