NAG1 Automatic Transmission

P0562-BATTERY VOLTAGE LOW





For a complete wiring diagram Refer to Diagrams/Electrical Electrical Diagrams


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. NAG1 - Pre-Diagnostic Troubleshooting Procedure



Diagnostic Test


1. CHECK FOR ENGINE CHARGING SYSTEM DTCs

With the scan tool, read Engine DTCs.

Are there any Engine Charging System DTCs present?

Yes

- Refer to Engine Electrical Diagnostics and perform the appropriate symptom.

No

- Go To 2



2. CHECK SYSTEM VOLTAGE

Start the engine.

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





Turn the ignition off to the lock position.

Remove the Transmission Control relay.

Ignition on, engine not running.

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





Turn the ignition off to the lock position.

Remove the Transmission Relay.

Connect a jumper wire between the (A1) B (+) circuit and the (F2) Transmission Relay Output circuit in the Transmission Relay connector.

Start the engine.

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





Turn the ignition off to the lock position.

Disconnect the TCM C1 harness connector.

Ignition on, engine not running.

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





Turn the ignition off to the lock position.

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) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace the TCM.
- Perform NAG1 TRANSMISSION VERIFICATION TEST. NAG1 Transmission Verification Test

No

- Repair the (Z912) Ground circuit for high resistance.



7. INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set this DTC are not present at this time.

Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.

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.