Pinpoint Test M: DTC B1318

Power Liftgate

Pinpoint Test M: DTC B1318

Normal Operation

- DTC B1318 (Battery Voltage Low)- a continuous and on-demand DTC that sets when the Liftgate/Trunk Module (LTM) detects battery voltage below 9 volts on the voltage supply circuits for 3 seconds or longer.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- High circuit resistance

- LTM (Liftgate/Trunk Module)

PINPOINT TEST M : DTC B1318

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector

M1 RECHECK THE LTM (Liftgate/Trunk Module) DTCs

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: Liftgate/Trunk Module (LTM) Self-Test.

- Clear the DTCs.

- Wait 10 seconds.

- Repeat the LTM (Liftgate/Trunk Module) self-test.

Is DTC B1318 still present?

Yes
GO to M2.

No
The system is operating correctly at this time. The DTC may have been set due to a previous low battery voltage condition.

M2 CHECK FOR CHARGING SYSTEM DTCs IN THE PCM

- Enter the following diagnostic mode on the scan tool: PCM Self-Test.

- Carry out the PCM Key ON Engine OFF (KOEO) self-test.

Are any charging system DTCs set in the PCM?

Yes
REFER to Charging System.

No
GO to M3.

M3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE

- Check the battery condition and verify the battery is fully charged.

Is the battery OK and fully charged?

Yes
GO to M4.

No
REFER to Battery.

M4 CHECK THE LTM (Liftgate/Trunk Module) VOLTAGE (VBAT_#1) AND (VBAT_#2) PIDs

- Ignition ON.

- Measure and record the voltage at the battery.

- Enter the following diagnostic mode on the scan tool: LTM (Liftgate/Trunk Module) DataLogger.

- Monitor the LTM (Liftgate/Trunk Module) voltage PIDs (VBAT_#1) and (VBAT_#2).

Are the PID voltages within 0.2 volt of the recorded battery voltage?

Yes
GO to M7.

No
GO to M5.

M5 CHECK THE LTM (Liftgate/Trunk Module) VOLTAGE SUPPLY

- Ignition OFF.

- Disconnect: LTM (Liftgate/Trunk Module) C4174A.

- Measure the voltage between LTM (Liftgate/Trunk Module) C4174A-4, circuit SBB07 (WH/RD), harness side and ground; and between LTM (Liftgate/Trunk Module) C4174A-9, circuit SBP09 (RD), harness side and ground.






Are the voltages within 0.2 volt of the recorded battery voltage?

Yes
GO to M6.

No
REPAIR the circuit in question for high resistance. CLEAR the DTC. REPEAT the self-test.

M6 CHECK THE LTM (Liftgate/Trunk Module) GROUND CIRCUIT

- Measure the resistance between LTM (Liftgate/Trunk Module) C4174A-1, circuit GD149 (BK/GY), harness side and ground.






Is the resistance less than 5 ohms?

Yes
GO to M7.

No
REPAIR circuit GD149 (BK/GY) for high resistance. CLEAR the DTCs. REPEAT the self-test.

M7 CHECK FOR CORRECT LTM (Liftgate/Trunk Module) OPERATION

- Disconnect all the LTM (Liftgate/Trunk Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the LTM (Liftgate/Trunk Module) connectors and make sure they are seated correctly.

- Make sure the liftgate is fully closed.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new LTM (Liftgate/Trunk Module). REFER to Liftgate/Trunk Module (LTM) Service and Repair. TEST the system for normal operation.

No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.