B2101

B2101-IGNITION RUN/START INPUT CIRCUIT LOW





For a complete wiring diagram refer to the Wiring Information Electrical Diagrams.

Theory of Operation

The Occupant Classification Module (OCM) monitors the CAN BUS message containing the battery voltage. If the battery voltage is below 10.0 volts the DTC be set active. The OCM receives operating voltage from the A21 Run/Start circuit by way of the PDC, C6 Fuse, and the F12 Fused Ignition Switch Output Switch Run/Start circuit. If the CAN BUS message containing the battery voltage drops below 10 ±0.25 volts for 3 seconds the DTC be set active.

- When Monitored:
At ignition ON or CAN BUS active, and the CAN BUS is RUN or signal not available, the OCM will monitor the CAN BUS message for battery voltage over 10.0 volts.

- Set Condition:
With the ignition on, and the CAN BUS message contains battery voltage less than 10.0 ±0.25 volts for 3 seconds.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Restraints System Pre-Diagnostic Procedure.

1. VERIFY OCM COMMUNICATION

NOTE: Ensure the battery is fully charged.

1. Turn the ignition on.
2. With the scan tool, read OCM DTC.

Does the scan tool display active: No Response from OCM?

Yes

- Perform LOST COMMUNICATION WITH OCM procedure. Lost Communication With OCM.

No

- Go To 2

2. VERIFY ACTIVE B2101-IGNITION RUN/START INPUT CIRCUIT LOW.
1. With the scan tool, read ORC DTC.

Does the scan tool display active: B2101-IGNITION RUN/START INPUT CIRCUIT LOW?

Yes

- Go To 3

No

- Perform the RESTRAINTS SYSTEM INTERMITTENT TEST. Restraints System Intermittent Test.

3. VERIFY F12 FUSED IGNITION SWITCH OUTPUT VOLTAGE

WARNING: Turn the ignition on, then reconnect the 12-volt battery. Failure to follow these instructions may result in possible serious or fatal injury.

1. With the scan tool, read battery voltage from the PCM.

Is the PCM battery voltage above 10.0 volts?

Yes

- WARNING: Turn the ignition off, disconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

- WARNING: If the Occupant Classification Module (OCM) is dropped at any time, it must be replaced. Failure to follow these instructions may result in possible serious or fatal injury.

- Replace the OCM.
- Perform the OCM REZERO. Testing and Inspection.

No

- Repair the low battery or charging system.
- Perform the RESTRAINTS SYSTEM VERIFICATION TEST. Restraints System Verification Test.