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.

SYS.OK|MANUAL.DB● LIVE

HOMESERVICE MANUALSJEEP2009COMMANDER SPORT, 3.7 K, RWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTANTI-THEFT SYSTEMSDRIVER DOOR MODULE (DDM) - ELECTRICAL DIAGNOSTICSDTC TROUBLESHOOTINGU1001-CAN B BUS (-) CIRCUITDIAGNOSTIC TEST

2009 Jeep Commander Sport, 3.7 K, RWD

Diagnostic Test

2009 Jeep Commander Sport, 3.7 K, RWDSECTION Diagnostic Test

TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, record and erase DTCs.
3. Cycle the ignition from on to off 3 times.
4. Turn the ignition on.
5. With the scan tool, read DTCs.
  Does the scan tool display: U1001 CAN B BUS (-) CIRCUIT?
  
  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 .
CHECK FOR ACTIVE CAN B BUS RELATED DTCS IN THE FRONT CONTROL MODULE (FCM)
1. With the scan tool, read Front Control Module (FCM) DTCs
  Does the scan tool display any active CAN B BUS related DTCs?
  
  Yes
  - Diagnose and repair the DTCs. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Diagnosis and Testing .
  No
  - Go to step 3
CHECK THE (D54) CAN B BUS (-) CIRCUIT FOR AN OPEN BETWEEN THE FRONT CONTROL MODULE AND THE PASSENGER DOOR MODULE

Fig 1: Checking CAN B BUS (-) Circuit For An Open Between Front Control Module & Passenger Door Module
Courtesy of CHRYSLER LLC
1. Turn the ignition off.
2. Disconnect the Passenger Door Module C2 connector.
3. Disconnect the Front Control Module C1 connector.
4. Measure the resistance of the (D54) Can B Bus (-) circuit between the Front Control Module C1 connector and the Passenger Door Module C2 connector.
  Is the resistance below 2.0 ohms?
  
  Yes
  - Replace the Passenger Door Module 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 (D54) Can B Bus (-) circuit for an open.
  - Perform the BODY VERIFICATION TEST. Refer to DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

Shop Manual-Ready Tools Free Quote Check Quote Shield Pro

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.