Page 22 of 5267
P0703-BRAKE SWITCH 2 PERFORMANCE
For a complete wiring diagramRefer to Section 8W.
Page 23 of 5267

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)
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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
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5.(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT OPEN
Turn the ignition off.
Measure the resistance of the (V32) Brake Switch No.2 Signal circuit
from the Stop Lamp Switch harness connector to the appropriate termi-
nal of special tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 6
No>>
Repair the open in the (V32) Brake Switch No.2 Signal cir-
cuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
6.(V32) BRAKE SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (V32) Brake Switch
No.2 Signal circuit in the Stop Lamp Switch harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short to ground in the (V32) Brake Switch No.2
Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 7
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7.(B29) BRAKE SWITCH NO.1 SIGNAL CIRCUIT OPEN
Measure the resistance of the (B29) Brake Switch No.1 Signal circuit
from the Stop Lamp Switch harness connector to the appropriate termi-
nal of special tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 8
No>>
Repair the open in the (B29) Brake Switch No.1 Signal cir-
cuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
8.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?
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)
Page 118 of 5267

When Monitored:
Ignition on and vehicle moving. Cruise is learned and customer is trying touse the Cruise.
Set Condition:
The PCM recognizes rear wheel speed is greater than front wheel speed. One trip fault.
Possible Causes
ACTIVE BUS OR COMMUNICATION DTCS
TIRE CIRCUMFERENCE
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
NOTE: Check for any Bus Communication DTCs. If no Bus Communication DTCs are set, check for active
DTCs stored in the Ant-Lock Brake Module. Any Bus Communication DTCs or VSSDTCs in the Ant-Lock
Brake Module must be properly diagnosed before continuing.
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.VISUAL INSPECTION
NOTE: This code can set due to tire circumference differences and from the front or rear wheels being on
a slippery surface while the opposite tires are not.
This code may also set on a hard acceleration on loose gravel or during otheroff road driving conditions.
Check tire pressure of all the tires.
Checktirewearonallthetires.
Ask the customer what the road and driving conditions were like when the fault set.
Were any problems found?
Ye s>>
Repair as necessary. If the code set during a front OR rear wheel spin condition, no repair is necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
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When Monitored:
Ignition on and vehicle moving. Brake pedal must not be applied.
Set Condition:
The PCM recognizes front axle speed is greater than rear axle speed. One tripfault.
Possible Causes
ACTIVE BUS OR COMMUNICATION DTCS
TIRE CIRCUMFERENCE
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
Ignition on, engine not running.
NOTE: Check for any Bus Communication DTCs. If no Bus Communication DTCs are set, check for active
DTCs stored in the Ant-Lock Brake Module. Any Bus Communication DTCs or VSSDTCs in the Ant-Lock
Brake Module must be properly diagnosed before continuing.
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.VISUAL INSPECTION
NOTE: This code can set due to tire circumference differences and from the front or rear wheels being on
a slippery surface while the opposite tires are not.
This code may also set on a hard acceleration on loose gravel or during otheroff road driving conditions.
Check tire pressure of all the tires.
Checktirewearonallthetires.
Ask the customer what the road and driving conditions were like when the fault set.
Were any problems found?
Ye s>>
Repair as necessary. If the code set during a front OR rear wheel spin condition, no repair is necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
Page 124 of 5267
P1572-BRAKE PEDAL STUCK ON
For a complete wiring diagramRefer to Section 8W.