NAG1 Automatic Transmission

P0563 - SYSTEM OVERVOLTAGE





When Monitored and Set Condition

- When Monitored: Always monitored with system active at each ignition cycle.
- Set Condition: System voltage above 16.9 volts with the engine and transmission input speed sensors above 2000 RPM for 60 seconds.





For a complete Transmission Control Module Circuit Diagram, [1][2]Automatic Transmission/Transaxle.

Diagnostic Test

1. PRE-DIAGNOSTIC CHECK OUT
NOTE: Low fluid level can be the cause of many transmission problems. If the fluid level is low, locate and repair the leak then check and adjust the fluid level.

NOTE: Always perform diagnostics with a fully charged battery to avoid false symptoms.

With the scan tool, read Engine DTCs. Check and repair all engine DTCs prior to performing transmission symptom diagnostics.
With the scan tool, read and record all Transmission DTCs.

NOTE: Check connectors - Clean/repair as necessary. Poor pin to terminal connections can set DTCs.

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Repair as necessary.
Most DTCs set on start up but some must be set by driving the vehicle such that all diagnostic monitors have run.

NOTE: Check for any Technical Service Bulletins that may apply.

Perform this procedure prior to Symptom diagnosis.

Continue

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2. VEHICLE JUMP STARTED IMPROPERLY
Determine if the vehicle was jump started improperly.

NOTE: If the battery was jump started with the batteries in series, the System Overvoltage DTC will be set.

Was the vehicle jump started improperly?

Yes

- Erase the DTC if the vehicle was jump started improperly.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test

No

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3. ENGINE CHARGING SYSTEM DTCS PRESENT
With the ignition on.
With the scan tool, read Engine DTCs.
Are any Engine Charging System DTCs present?

Yes

- Diagnose and repair the DTC(s).

No

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4. TRACTION SYSTEM RELAY OUTPUT VOLTAGE HIGH AT TCM




Turn the ignition off.
Disconnect the TCM C1 harness connector.

NOTE: Check connectors - Clean/repair as necessary.

Start the engine.
Increase the engine speed to 1500 RPM.
Measure the voltage of the Traction System Relay Output circuit in the TCM C1 harness connector.
Is the voltage below 16.9 volts?

Yes

- Replace the Transmission Control Module. Transmission Control Module - Removal.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. Transmission Verification Test

No

- Diagnose and repair the DTC(s).