FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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B2108







B2108-IGNITION SWITCH SENSE INPUT CIRCUIT LOW





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on.

- Set Condition:
The BCM detects a LOW condition on the (G20) Ignition Switch Sense circuit.





Diagnostic Test

1. CHECK FOR AN ACTIVE DTC
Turn the ignition on.
With the scan tool, record and erase DTCs.
Wait 30 seconds.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- The condition that caused this code to set is not present at this time. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.
- PERFORM BODY VERIFICATION TEST - VER 1. Body Verification Test

2. IGNITION SWITCH




Turn the ignition off.
Disconnect the Ignition Switch harness connector.
Connect a jumper wire between the (F20) Fused Ignition Switch Output (Run/Start) circuit and the (A106) Fused B+ circuit.
With the scan tool, erase and read DTCs.
Does the scan tool display DTC: B2109-IGNITION SWITCH SENSE INPUT CIRCUIT HIGH as active?

Yes

- Replace the Ignition Switch.
- PERFORM the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To 3

3. (G20) IGNITION SWITCH SENSE CIRCUIT SHORT TO GROUND




Remove the jumper wire.
Disconnect the BCM C5 harness connector.
Measure the resistance between the (G20) Ignition Switch Sense circuit and ground.
Is the resistance below 10K ohms?

Yes

- Repair the (G20) Ignition Switch Sense circuit for a short to ground.
- PERFORM the BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Replace the BCM.
- PERFORM the BODY VERIFICATION TEST - VER 1. Body Verification Test.