Page 713 of 5267

4.BATTERY TERMINAL CONNECTIONS
Visually inspect the positive and negative connections at the batteries and inspect the battery negative connections
at the engine block.
Are the connections free of corrosion and are they tight?
Ye s>>
Go To 5
No>>
Repair the poor connections.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
5.ACCESSORY WIRING
Check for add-on or accessory wiring at positive (+) terminal of the battery
Are there any damaged wires at the battery?
Ye s>>
Repair accessory wiring.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 6
6.BATTERY(S)
Perform battery load test using the Midtronics Micro 420 battery system tester.
Did the battery(s) pass the test?
Ye s>>
Go To 7
No>>
Replace the weak battery or batteries.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
7.HIGH RESISTANCE IN WIRE HARNESS
Turn the ignition off.
Disconnect the ECM harness connectors.
Disconnect the battery terminals.
Measure the resistance from the positive and negative battery posts to
the appropriate circuits in the ECM harness connector
Is the resistance less than 10 Ohms?
Ye s>>
Go To 8
No>>
Repair the high resistance in the wire harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 714 of 5267
8.ECM
Reconnect the battery terminals.
Measure and record the voltage between battery positive pins of the
ECM connector and the battery negative circuits of the ECM harness
connector.
Reconnect the ECM harness connectors.
Use the scan tool to measure and record battery voltage.
Are the readings within 3 volts of each other?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diag-
nostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 715 of 5267
P0563-BATTERY VOLTAGE HIGH
For a complete wiring diagramRefer to Section 8W.
Page 716 of 5267

When Monitored:
With the key on or the engine running.
Set Condition:
The battery voltage detected by the ECM is greater than a calibrated value.
Possible Causes
P0622 PRESENT
P2502 PRESENT
P2504 PRESENT
BATTERIES IMPROPERLY INSTALLED
ECM
INTERMITTENT CONDITION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
Diagnostic Test
1.P0622 PRESENT
With the scan tool, read DTCs.
Is P0622 set?
Ye s>>
Repair P0622 first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 2
2.P2502 PRESENT
With the scan tool, read DTCs.
Is P2502 set?
Ye s>>
Repair P2502 first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 3
3.P2504 PRESENT
With the scan tool, read DTCs.
Is P2504 set?
Ye s>>
Repair P2504 first.
Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)
No>>
Go To 4
Page 717 of 5267

4.BATTERIES IMPROPERLY INSTALLED
Disconnect the ECM harness connectors.
Measure the battery voltage between the positive circuits and ground of
the ECM harness connector.
Is the voltage less than 19 volts?
Ye s>>
Go To 5
No>>
Install the battery system correctly.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
5.ECM
Reconnect the battery terminals.
Measure and record the voltage between battery positive pins of the
ECM connector and the battery negative circuits of the ECM harness
connector.
Reconnect the ECM harness connectors.
Use the scan tool to measure and record battery voltage.
Are the readings within 3 volts of each other?
Ye s>>
Refer to the INTERMITTENT CONDITION Symptom (Diag-
nostic Procedure). (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
No>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
Page 718 of 5267
P0572-LOW VOLTAGE DETECTED AT THE BRAKE SWITCH
For a complete wiring diagramRefer to Section 8W.
Page 719 of 5267

When Monitored:
While the ignition is on
Set Condition:
The brake switch status is = to OFF and the not brake switch status is = to ON for a calibrated amount of
time..
Possible Causes
DAMAGED WIRING HARNESS OR CONNECTORS
BRAKE SWITCH CIRCUIT SHORTED TO GROUND (BRAKE SWITCH WILL ALWAYS BE OFF)
BRAKE SWITCH
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.BRAKE SWITCH CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the brake switch connection. Inspect the pins and connector
for damage, corrosion, etc.
Disconnect the ECM connectors. Inspect the pins and connector for
damage, corrosion, etc.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the brake switch circuit in the ECM
connector and battery negative.
Is the resistance less than 10 ohms?
Ye s>>
Repair the Brake switch circuit shorted to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 2
Page 720 of 5267
2.BRAKE SWITCH CIRCUIT SHORTED TO OTHER CIRCUITS IN HARNESS
Measure the resistance between the brake switch wire in the ECM con-
nector and all other pins in the ECM connector.
Is the resistance less than 10 ohms?
Ye s>>
Repair or replace the harness.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 3
3.ECM
Reconnect the ECM connectors.
Measure the resistance between the brake switch circuit at the switch
connector and battery negative.
Is the resistance less than 10 ohms?
Ye s>>
Replace the ECM.
Perform POWERTRAIN VERIFICATION TEST VER - 1
(DIESEL). (Refer to 8 - ELECTRICAL/ELECTRONIC CON-
TROL MODULES/ENGINE CONTROL MODULE - DIAG-
NOSIS AND TESTING)
No>>
Go To 4