Transmission Control Module (TCM)

P0562-BATTERY VOLTAGE LOW





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 if the monitored battery voltage drops below 8.5 volts and a temporary limp in will be activated. If the voltage rises above 9.0 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 is less than 8.5 volts with a engine speed greater than 2000 RPM for a least 60 seconds.

- When Monitored:
Continuously with the ignition on.

- Set Condition:
When monitored battery voltage drops below 8.5 volts.





Always perform the NAG1 Pre-Diagnostic Troubleshooting procedure before proceeding Initial Inspection and Diagnostic Overview.

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

Are there any Engine Charging System DTCs present?

Yes

- Perform the appropriate diagnostic procedure.

No

- Go To 2

2. CHECK SYSTEM VOLTAGE
1. Start the engine.
2. With the scan tool, under transmission, check system voltage.

Is the transmission system voltage above 9.0 volts?

Yes

- Go To 7

No

- Go To 3

3. CHECK THE (A1) B (+) CIRCUIT




1. Turn the ignition off to the lock position.
2. Remove the Transmission Control relay.
3. Ignition on, engine not running.
4. Using a 12-volt test light connected to ground, check the (A1) B (+) circuit in the Transmission Relay connector.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the (A1) B (+) circuit for high resistance.
- Perform NAG1 TRANSMISSION VERIFICATION TEST NAG1 Transmission Verification Test.

4. CHECK THE (F942) TRANSMISSION RELAY OUTPUT CIRCUIT




1. Turn the ignition off to the lock position.
2. Remove the Transmission Relay.
3. Connect a jumper wire between the (A1) B (+) circuit and the (F2) Transmission Relay Output circuit in the Transmission Relay connector.
4. Start the engine.
5. With the scan tool, under transmission, check system voltage.

Is the transmission system voltage above 9.0 volts?

Yes

- Replace the Transmission Relay.
- Perform NAG1 TRANSMISSION VERIFICATION TEST NAG1 Transmission Verification Test.

No

- Go To 5

5. CHECK THE (F942) FUSED TRANSMISSION RELAY OUTPUT CIRCUIT




1. Turn the ignition off to the lock position.
2. Disconnect the TCM C1 harness connector.
3. Ignition on, engine not running.
4. Using a 12-volt test light connected to ground, check the (F942) Fused Transmission Relay Output circuit in the TCM C1 harness connector.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 6

No

- Repair the (F942) Fused Transmission Relay Output circuit for high resistance. Make sure the check the fuse cavities.
- Perform NAG1 TRANSMISSION VERIFICATION TEST NAG1 Transmission Verification Test.

6. CHECK (Z912) GROUND CIRCUIT




1. Turn the ignition off to the lock position.
2. Using a 12-volt test light connected to 12-volts, check the (Z912) Ground circuit in the TCM C1 harness connector.

Does the test light illuminate brightly?

Yes

- Using the schematics as a guide, check the Transmission Control Module (TCM) connectors and 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.

No

- Repair the (Z912) Ground circuit for high resistance.
- Perform NAG1 TRANSMISSION VERIFICATION TEST NAG1 Transmission Verification Test.

7. 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.

Where there any problems found?

Yes

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

No

- Test Complete.