Transmission Control Module (TCM) - NAG1

P0563-BATTERY VOLTAGE HIGH





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Transmission Control Module (TCM) monitors ignition voltage. The DTC will set and temporary limp-in will be activated, if the monitored battery voltage rises above 16.9 volts. If the voltage drops below 16.4 volts, normal operations is resumed and the TCM will record the DTC as a one trip fault. The DTC will only mature to a full DTC if the voltage rises above 16.9 volts with a engine speed greater than 2000 RPM for a least 60 seconds.

- When Monitored:
Continuously with the ignition on.

- Set Condition:
When the monitored battery voltage rises above 16.9 volts.





Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding. NAG1 Pre-Diagnostic Troubleshooting Procedure

1. CHECK FOR CHARGING SYSTEM DTCS
1. With the scan tool, read Engine DTCs.

NOTE: This includes any one trip faults.

Are there any Engine Charging System DTCs present?

Yes

- Charging System and repair any Charging System symptoms before proceeding. After repairing the Charging System, perform the Transmission Verification test to verify the transmission and or controller was not damaged.

No

- Go To 2

2. CHECK IF VOLTAGE IS GREATER THAN 16.9 VOLTS
1. Start the engine and raise the engine speed to 2000 rpm.
2. With the scan tool, monitor the Transmission system voltage for at least 60 seconds.

Does the Transmission system voltage read above 16.9 volts for any period of time?

Yes

- Go To 4

No

- Go To 3

3. VERIFY IF VEHICLE WAS JUMP STARTED WITH 24-VOLT SYSTEM
1. Verify if the vehicle was jump started by another vehicle using a 24-volt charging system.

Was the vehicle jump started by another vehicle using a 24-volt charging system?

Yes

- This is the cause of the DTC. Erase the DTC and return the vehicle to the customer.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Go To 5

4. CHECK BATTERY VOLTAGE




1. Start the engine and raise the engine speed to 2000 rpm.
2. With the scan tool, read the Transmission system voltage.
3. With a voltmeter, measure the battery voltage at the battery.
4. Compare the readings.

Does the voltage readings match between the Transmission scan tool reading and the battery voltmeter reading?

Yes

- Repair the charging system for an over charging condition.Charging System and repair any Charging System symptoms before proceeding. After repairing the Charging System, perform the Transmission Verification test to verify the transmission and or controller was not damaged.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Using the schematics as a guide, check the Transmission Control Module (TCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the TCM.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

5. INTERMITTENT WIRING AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wires while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Test Complete.