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 MANUALSJEEP2009COMMANDER SPORT, 3.7 K, AWDREPAIR AND DIAGNOSISENGINE PERFORMANCEIGNITION SYSTEM(CABIN COMPARTMENT NODE (CCN) - ELECTRICAL DIAGNOSTICS)DTC TROUBLESHOOTINGU1149-LOST COMMUNICATION WITH MULTI-FUNCTION SWITCHDIAGNOSTIC TEST
2009 Jeep Commander Sport, 3.7 K, AWD
Diagnostic Test
2009 Jeep Commander Sport, 3.7 K, AWDSECTION Diagnostic Test
- CHECK FOR AN ACTIVE DTC NOTE: Before proceeding with this diagnostic procedure, verify the Left and Right Multifunction Switch and Clockspring harness connectors are properly seated and verify proper pin terminal tension. A loose connection at any of these connectors may cause this DTC to set.
- Turn the ignition on.
- With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go to step 2
No
- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- (D500) LIN BUS CIRCUIT OPEN
- Turn the ignition off.
- Disconnect the Multifunction Switch C1 harness connector.
- Turn the ignition on.
- Measure the voltage of the (D500) LIN BUS circuit.
Is the voltage above 5 volts?
Yes
- Go to step 3
No
- Repair the (D500) LIN BUS circuit for an open
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- (F941) FUSED IGNITION RUN/START CONTROL OUTPUT CIRCUIT OPEN
- Measure the voltage of the (F941) Fused Ignition Run/Start Control Output circuit.
Is the voltage above 10 volts?
Yes
- Go to step 4
No
- Repair the (F941) Fused Ignition Run/Start Control Output circuit for an open.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- Measure the voltage of the (F941) Fused Ignition Run/Start Control Output circuit.
- (A114) FUSED B(+) (I.O.D.) CIRCUIT OPEN
- Measure the voltage of the (A114) Fused B(+) (I.O.D.) circuit.
Is the voltage above 10 volts?
Yes
- Go to step 5
No
- Repair the (A114) Fused B(+) (I.O.D.) circuit for an open.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- Measure the voltage of the (A114) Fused B(+) (I.O.D.) circuit.
- (Z907) GROUND CIRCUIT OPEN
- Turn the ignition off.
- Measure the resistance between ground and the (Z907) Ground circuit.
Is the resistance below 10K Ohms?
Yes
- Replace the Multifunction Switch in accordance with the Service Information.
- Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
No
- Repair the (Z907) Ground circuit for an open.
- 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.