Pinpoint Test L: DTC B1318
Fire Suppression System
Pinpoint Tests
Pinpoint Test L: DTC B1318
Refer to Wiring Diagram Set 13, Power Distribution/SJB for schematic and connector information. Diagrams By Number
Normal Operation
The Fire Suppression System Module (FSSM) monitors input voltage for correct operation and sets DTC B1318 if the FSSM detects input voltage below 9 volts, or below 9.5 volts if PCM and ABS messages are not received.
- DTC B1318 (Battery Voltage Low) - sets when the FSSM detects battery voltage below 9 volts or below 9.5 volts if PCM and ABS messages are not received.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- High circuit resistance
- FSSM
PINPOINT TEST L: 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 results in false resistance readings. Refer to Battery, Mounting and Cables Battery Disconnect.
-------------------------------------------------
L1 RETRIEVE ALL CMDTCs IN ALL MODULES
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Self-Test - All Continuous Memory Diagnostic Trouble Codes (CMDTCs).
- Is DTC B1318 present in one or more modules AND P0620, P0625, P0626 or P065B retrieved from the PCM?
Yes
REFER to Charging System Testing and Inspection to diagnose the charging system.
No
GO to L2.
-------------------------------------------------
L2 TEST BATTERY CONDITION
- Ignition OFF.
- Carry out the battery condition test. Refer to Battery, Mounting and Cables Testing and Inspection.
- Did the battery pass the condition test?
Yes
If the battery passed the condition test but required a recharge, REFER to Charging System Testing and Inspection to diagnose the charging system. CLEAR all CMDTCs. TEST the system for normal operation.
If the battery passed the condition test and did not require a recharge, GO to L3.
No
INSTALL a new battery. REFER to Battery, Mounting and Cables Battery. CLEAR all CMDTCs. TEST the FSSM for normal operation.
-------------------------------------------------
L3 CHECK THE CHARGING SYSTEM VOLTAGE
NOTE: Do not allow the engine speed to increase above 2,000 rpm while carrying out this step or the generator may self excite and result in default charging system output voltage. If engine speed goes above 2,000 rpm, shut the vehicle OFF and restart the engine before carrying out this step.
- Start the engine.
- With the headlights ON and HVAC fan on HIGH, run the engine at 1,500 rpm for a minimum of 2 minutes while measuring the battery voltage.
- Is the voltage between 13 and 15.2 volts?
Yes
GO to L4.
No
REFER to Charging System Testing and Inspection to diagnose the charging system. CLEAR all CMDTCs. TEST the FSSM for normal operation.
-------------------------------------------------
L4 CHECK THE FSSM VOLTAGE SUPPLY
- Measure the voltage of the battery:
- WARNING: To reduce the risk of accidental deployment, do not use any memory saver devices when depowering the fire suppression system. Failure to follow this instruction may result in serious personal injury.
- Depower the fire suppression system. Refer to Fire Suppression System Depowering and Repowering Procedures.
- Disconnect: FSSM C3281A.
- Repower the fire suppression system. Do not prove out the fire suppression system at this time. Refer to Fire Suppression System Depowering and Repowering Procedures.
- Ignition ON.
- Measure the voltage between the FSSM C3281A-1, circuit 2319 (RD/YE), harness side and ground.
- Is the voltage within 0.2 volt of the recorded battery voltage?
Yes
GO to L5.
No
REPAIR the circuit for high resistance. CLEAR the DTCs. REPEAT the self-test.
-------------------------------------------------
L5 CHECK THE FSSM GROUND CIRCUIT
- Ignition OFF.
- Measure the resistance between the FSSM C3281A-7, circuit 1203 (BK/LB), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to L6.
No
REPAIR the circuit for high resistance. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
-------------------------------------------------
L6 CHECK FOR CORRECT MODULE OPERATION
- Ignition OFF.
- WARNING: To reduce the risk of accidental deployment, do not use any memory saver devices when depowering the fire suppression system. Failure to follow this instruction may result in serious personal injury.
- Depower the fire suppression system. Refer to Fire Suppression System Depowering and Repowering Procedures.
- Disconnect: FSSM C3281A.
- Check for the following:
- corrosion
- damaged pins
- pushed-out pins
- Connect: FSSM C3281A.
- Repower the fire suppression system not prove out the fire suppression system at this time. Refer to Fire Suppression System Depowering and Repowering Procedures.
- Enter the following diagnostic mode on the scan tool: Self-Test - FSSM.
- Was the original DTCs retrieved on-demand during self-test?
Yes
INSTALL a new FSSM. REFER to Fire Suppression System Module (FSSM) Service and Repair. CLEAR all FSSM DTCs. REPEAT the self-test. PROVE OUT the fire suppression system. The repair is complete. RETURN the vehicle to the customer.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR all FSSM DTCs. PROVE OUT the fire suppression system. The repair is complete. RETURN the vehicle to the customer.
-------------------------------------------------