Pinpoint Test B: DTC B1318

Generic Electronic Module (GEM)

Pinpoint Test B: DTC B1318

Refer to Wiring Diagrams Set 13, Power Distribution for schematic and connector information. Electrical Diagrams

Normal Operation

- DTC B1318 (Battery Voltage Low)- a continuous memory DTC that sets when the GEM (Generic Electronic Module) detects battery voltage below 8.5 volts.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- High circuit resistance

- GEM (Generic Electronic Module)

PINPOINT TEST B : DTC B1318

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

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.

B1 RECHECK THE GEM (Generic Electronic Module) DTCs

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: GEM (Generic Electronic Module) Self-Test.

- Clear the DTCs. Repeat the GEM (Generic Electronic Module) self-test.

Is DTC B1318 still present?

Yes
GO to B2.

No
The system is operating normally at this time. The DTC may have been set previously during battery charging or while jump starting the vehicle.

B2 CHECK FOR CHARGING SYSTEM DTCs IN THE PCM

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

- Retrieve the continuous memory DTCs from the PCM.

Is DTC P0620:00, P0625:00, P0626:00 or P065B:00 set in the PCM?

Yes
REFER to Charging System.

No
GO to B3.

B3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE

- Ignition OFF.

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

Is the battery OK and fully charged?

Yes
GO to B4.

No
REFER to Charging System.

B4 CHECK THE GEM (Generic Electronic Module) VOLTAGE SUPPLY

- Measure and record the voltage at the battery.

- Disconnect: GEM (Generic Electronic Module) C201A.

- Ignition ON.

- Measure the voltage between the GEM (Generic Electronic Module) C201A-10, circuit 15-DK20 (GN/OG), harness side and ground.





Is the voltage within 0.2 volt of the recorded battery voltage?

Yes
GO to B5.

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

B5 CHECK THE GEM (Generic Electronic Module) GROUND CIRCUIT

- Ignition OFF.

- Disconnect: Negative Battery Cable.

- Disconnect: GEM (Generic Electronic Module) C201D.

- Measure the resistance between the GEM (Generic Electronic Module) C201D-3, circuit 31-DK20 (BK), harness side and ground.





Is the resistance less than 5 ohms?

Yes
CONNECT the negative battery cable. GO to B6.

No
REPAIR the circuit for high resistance. CONNECT the negative battery cable. TEST the system for normal operation.

B6 CHECK FOR CORRECT GEM (Generic Electronic Module) OPERATION

- Disconnect all the GEM (Generic Electronic Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the GEM (Generic Electronic Module) connectors and make sure they seat correctly.

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

Is the concern still present?

Yes
INSTALL a new GEM (Generic Electronic Module). REFER to Generic Electronic Module (GEM) . TEST the system for normal operation.

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