Pinpoint Test B: DTC B1318
Generic Electronic Module (GEM)
Pinpoint Tests
Pinpoint Test B: DTC B1318
Refer to Wiring Diagram Set 13, Power Distribution for schematic and connector information. Diagrams By Number
Normal Operation
- DTC B1318 (Battery Voltage Low) - a continuous memory DTC that sets when the GEM detects battery voltage below 8.5 volts.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- High circuit resistance
- GEM
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. Refer to Battery, Mounting and Cables Battery Disconnect.
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B1 RECHECK THE GEM DTCs
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: GEM Self-Test.
- Clear the DTCs. Repeat the GEM 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.
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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 Testing and Inspection.
No
GO to B3.
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B3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE
- Ignition OFF.
- Check the battery condition and verify the battery is fully charged. Refer to Battery, Mounting and Cables Testing and Inspection.
- Is the battery OK and fully charged?
Yes
GO to B4.
No
REFER to Charging System Testing and Inspection.
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B4 CHECK THE GEM VOLTAGE SUPPLY
- Measure and record the voltage at the battery.
- Disconnect: GEM C201A.
- Ignition ON.
- Measure the voltage between the GEM 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.
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B5 CHECK THE GEM GROUND CIRCUIT
- Ignition OFF.
- Disconnect: Negative Battery Cable.
- Disconnect: GEM C201D.
- Measure the resistance between the GEM 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.
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B6 CHECK FOR CORRECT GEM OPERATION
- Disconnect all the GEM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the GEM 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. REFER to Generic Electronic Module (GEM) Service and Repair. 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.
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