B2140

B2140-IGNITION START (REMOTE START) CONTROL CIRCUIT HIGH







Theory of Operation

The family of B2100 Diagnostic Trouble Codes (DTCs) typically describes ignition performance related faults. These are often caused by a contradiction of switch status information. For example, if an Electronic Control Unit (ECU) receives a bussed message indicating ignition switch position but the state of a hardwired ignition circuit indicates another switch position a B2100 series DTC would likely result.

These DTCs can be caused by a number of conditions including:

- loose connections
- missing or blown fuses
- faulty component
- vehicle no start or long crank time

Verify the proper operation of the starting system and verify that this DTC is active before proceeding with the diagnostic test.

- When Monitored:
With the ignition on.

- Set Condition:
The Front Control Module (FCM) will set this if the (F924) Fused Ignition Switch Output (Start) circuit is shorted to voltage for greater than 2 seconds.





1. CHECK FOR ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, read the active DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- If the DTC is stored, check for an intermittent condition. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. STARTER RELAY
1. Turn the ignition off.
2. Install a substitute relay in place of the original Starter Relay.
3. Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds.
4. With the scan tool, read the active FCM DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 3

No

- Replace the original Starter Relay.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. (F924) FUSED IGNITION SWITCH OUTPUT (START) CIRCUIT SHORTED TO VOLTAGE




1. Turn the ignition off.
2. Disconnect the IPM C2 harness connector.
3. Disconnect the FCM C1 harness connector.
4. Turn the ignition on.
5. Using a voltmeter, measure the voltage of the (F924) Fused Ignition Switch Output (Start) circuit and ground.

Is voltage present?

Yes

- Repair the (F924) Fused Ignition Switch Output (Start) circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the FCM.
- Perform the BODY VERIFICATION TEST. Body Verification Test.