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 MANUALSDODGE AND RAM2023PROMASTER 1500REPAIR AND DIAGNOSIS (SINGLE PAGE)ACCESSORIES & EQUIPMENTDRIVERS ASSISTANCE SYSTEMS - ADAS(ACTIVE CRUISE CONTROL (ACC) MODULE - ELECTRICAL DIAGNOSTICS)DTC TROUBLESHOOTINGC1403-86-ELECTRICAL POWER STEERING FAILURE - SIGNAL INVALIDDIAGNOSTIC TEST

2023 Dodge and Ram ProMaster 1500

Diagnostic Test

2023 Dodge and Ram ProMaster 1500SECTION Diagnostic Test

CHECK FOR ANY SERVICE BULLETINS OR MODULE SOFTWARE UPDATES
1. Check for any applicable Service Bulletins or Flash updates related to the DTC.
  Are there any applicable Service Bulletins or Flash updates?
  
  Yes
  - Perform the applicable repair.
  - Perform the ADAPTIVE CRUISE CONTROL VERIFICATION TEST. Refer to ADAPTIVE CRUISE CONTROL (ACC) VERIFICATION TEST.
  No
  - Go To 2
READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN
1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) and record on the repair order.
2. For future reference, run and save a vehicle Scan Report and all related recorded data.
3. With the scan tool, erase all DTCs.
4. Turn the ignition off for a minimum of 10.0 seconds.
5. Turn the ignition on.
6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
7. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 3
  No
  - Perform the TESTING FOR AN INTERMITTENT CONDITION procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION.
CHECK FOR EPS DTCS
1. Refer to the recorded DTCs.
  Are there any Electric Power Steering (EPS) Module DTCs present?
  
  Yes
  - Perform the applicable diagnostic procedure(s). Refer to DIAGNOSTIC CODE INDEX .
  No
  - Go To 4
REPLACE THE ELECTRIC POWER STEERING (EPS) MODULE AND RETEST FOR DTCS
1. Turn the ignition off.
2. Replace the EPS Module in accordance with the Service Information. Refer to GEAR, REMOVAL .
3. Connect the component and Electronic Control Unit (ECU) harness connectors.
4. Turn the ignition on.
5. With the scan tool, erase all DTCs.
6. Turn the ignition off for a minimum of 10.0 seconds.
7. Turn the ignition on.
8. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.
9. With the scan tool, read DTCs.
  Did the DTC return?
  
  Yes
  - Go To 5
  No
  - Replacing the faulty EPS Module repaired the fault.
  - Perform the ADAPTIVE CRUISE CONTROL VERIFICATION TEST. Refer to ADAPTIVE CRUISE CONTROL (ACC) VERIFICATION TEST.
CHECK RELATED ACC AND COMPONENT CONNECTIONS
1. Turn the ignition off.
2. Disconnect all ACC harness connectors.
3. Disconnect all related in-line harness connections (if equipped).
4. Disconnect the related component harness connectors.
5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
6. Reconnect all ACC harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
9. With the scan tool, erase DTCs.
10. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
11. With the scan tool, read ACC DTCs.
  Did the DTC return?
  
  Yes
  - Replace and program the Adaptive Cruise Control (ACC) Module in accordance with the Service Information. Refer to MODULE, ADAPTIVE CRUISE CONTROL (ACC), REMOVAL .
  - Perform the ADAPTIVE CRUISE CONTROL VERIFICATION TEST. Refer to ADAPTIVE CRUISE CONTROL (ACC) VERIFICATION TEST.
  No
  - The wiring or poor connection has been repaired.
  - Perform the ADAPTIVE CRUISE CONTROL VERIFICATION TEST. Refer to ADAPTIVE CRUISE CONTROL (ACC) VERIFICATION TEST.

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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.