NAG1 Automatic Transmission
P0562-BATTERY VOLTAGE LOW
For a complete wiring diagram Consult Diagrams/Electrical
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 Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview
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
- Diagnose and repair the DTC(s).
- Perform NAG1 TRANSMISSION VERIFICATION TEST.Verification Tests
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 4
3. CHECK THE TRANSMISSION RELAY
Turn the ignition off to the lock position.
Remove the Transmission Relay.
Install a substitute relay
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.Verification Tests
No
- Go to 4
4. CHECK FUSED 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 Fused 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 5
No
- Repair the Fused B (+) circuit for high resistance.
- Perform NAG1 TRANSMISSION VERIFICATION TEST.Verification Tests
5. CHECK THE TRANSMISSION RELAY OUTPUT CIRCUIT
Turn the ignition off to the lock position.
Disconnect the TCM C1 harness connector.
Remove the Transmission Control Relay.
Connect a jumper wire between the Fused B (+) circuit and the Transmission Relay Output circuit.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, check the 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
- Using schematic as a guide, repair the Fused Transmission Relay Output circuit for high resistance.
- Perform NAG1 TRANSMISSION VERIFICATION TEST.Verification Tests
6. CHECK GROUND CIRCUIT
Turn the ignition off to the lock position.
Using a 12-volt test light connected to 12-volts, check the 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) pins, terminals, and connectors 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.Verification Tests
No
- Repair the Ground circuit for high resistance.
- Perform NAG1 TRANSMISSION VERIFICATION TEST.Verification Tests
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.Verification Tests
No
- Test Complete.