B2122

B2122-IGNITION RUN CONTROL CIRCUIT LOW





For a complete wiring diagram Refer to Diagrams/Electrical.

- When Monitored:

With the ignition on.

- Set Condition:

The Front Control Module will set this DTC within 500ms if the (F921) or (F923) Run Relay Control circuit voltage is open or shorted to ground.





Diagnostic Test

1.CHECK FOR ACTIVE DTC

With the scan tool, read the active DTC's.

Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds.

With the scan tool, read the active DTC's.

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.

2.RUN RELAY

Turn the ignition off.

Install a substitute Run Relay in place of the original Run Relay.

Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 90 seconds.

With the scan tool, read the active FCM DTC's.

Does the scan tool display this DTC as active?

Yes

- Go To 3

No

- Replace the original Run Relay.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

3.(F921) or (F923) RUN RELAY CONTROL CIRCUIT OPEN





Turn the ignition off.

Remove the FCM from the IPM.

Remove the Run Relay from the Rear Power Distribution Module.

NOTE: This circuit contains a diode. When checking resistance of this circuit the red ohmmeter lead must be connected to the Run Relay cavity (85) and the black ohmmeter lead must be connected to the FCM-PDM connector.

NOTE: Ensure the diode is installed correctly in the Rear Power Distribution Module.

Measure the resistance of the Run Relay Control circuit.

Is the resistance below 10.0 ohms?

Yes

- Go To 4

No

- Repair the Run Relay Control circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4.(F921) RUN RELAY CONTROL CIRCUIT SHORTED TO GROUND





NOTE: This circuit contains a diode. When checking for a short to ground you must check both sides of the diode.

NOTE: Ensure the diode is installed correctly in the Rear Power Distribution Module.

Measure the resistance between ground and the (F921) Run Relay Control circuit at the Run Relay cavity (85).

Is the resistance below 10.0 ohms?

Yes

- Repair the (F921) Run Relay Control circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Go To 5

5.(F923) RUN RELAY CONTROL CIRCUIT SHORTED TO GROUND





NOTE: This circuit contains a diode. When checking for a short to ground you must check both sides of the diode.

NOTE: Ensure the diode is installed correctly in the Rear Power Distribution Module.

Measure the resistance between ground and the (F923) Run Relay Control circuit at the FCM-PDM connector.

Is the resistance below 10.0 ohms?

Yes

- Repair the (F923) Run Relay Control circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

No

- Inspect the wiring and connectors for damage or shorted circuits. If ok, replace and program the Front Control Module.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test