Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSJEEP2009GRAND CHEROKEE OVERLAND, 3.0 M, RWDREPAIR AND DIAGNOSISACCESSORIES & EQUIPMENTWINDOW MOTORS & REGULATORS(CABIN COMPARTMENT NODE (CCN) - ELECTRICAL DIAGNOSTICS)DTC TROUBLESHOOTINGB2123-IGNITION RUN CONTROL CIRCUIT HIGHDIAGNOSTIC TEST
2009 Jeep Grand Cherokee Overland, 3.0 M, RWD
Diagnostic Test
2009 Jeep Grand Cherokee Overland, 3.0 M, RWDSECTION Diagnostic Test
- TEST FOR INTERMITTENT CONDITION
- With the scan tool, record and erase DTCs
- Cycle the ignition from on to off.
- Turn the ignition on.
- With the scan tool, read DTCs.
Does the scan tool display: B2123-IGNITION RUN CONTROL CIRCUIT HIGH?
Yes
- Go to step 2
No
- The conditions that caused this code to set are not present at this time. Using the SYSTEM WIRING DIAGRAMS as a guide, inspect the wiring and connectors.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- IGNITION RUN RELAY
- Turn the ignition off.
- Install a substitute relay in place of the original Ignition Run Relay.
- Cycle the ignition switch from off to on, leaving the ignition on for a minimum of 30 seconds.
- With the scan tool, read the DTCs.
Does the scan tool display this DTC as active?
Yes
- Go to step 3
No
- Replace the original Ignition Run Relay.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- JUNCTION BLOCK NOTE: Perform this test with the relay removed.
- Turn the ignition off.
- Disconnect the Junction Block C2 connector (on top of junction block).
- From the Relay cavity 85, measure for voltage.
Is voltage present?
Yes
- Replace the Junction Block in accordance with Service Information.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
No
- Go to step 4
- (F102) IGNITION RUN RELAY CONTROL CIRCUIT SHORTED TO BATTERY
- Disconnect the Junction Block C2 connector (on top of junction block).
- Disconnect the Cluster C2 harness connector.
- Measure the voltage between ground and the (F102) Ignition Run Relay Control circuit in the Cluster C2 connector.
- Turn the ignition on.
Is there any voltage present?
Yes
- Repair the (F102) Ignition Run Relay Control circuit for a short to voltage.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
No
- Replace the Cluster in accordance with Service Information.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.