U1135 – Lost Communication with Instrument Panel Cluster (IPC) Control Module.

The ODBII code U1135 indicates a loss of communication between the vehicle’s control module and the Instrument Panel Cluster (IPC) control module, suggesting a potential issue with wiring, connectors, or the IPC itself.

The severity of ODBII code U1135 is generally considered moderate to severe.

Common Causes For: U1134 SCP (J1850) Invalid or Missing Data for Ignition Switch / Starter

• Faulty Instrument Panel Cluster (IPC) Control Module
• Damaged wiring or connectors
• Poor ground connection
• Faulty communication network (CAN bus issues)
• Blown fuse related to IPC
• Corroded terminals
• Software or firmware issues in the IPC
• Malfunctioning body control module (BCM)

Common misdiagnosis for U1135 Lost Communication with Instrument Panel Cluster (IPC) Control Module.

• Faulty Instrument Panel Cluster (IPC)
• Wiring issues or shorts in the communication lines
• Faulty Body Control Module (BCM)
• Power supply issues to the IPC
• Faulty or corroded connectors
• Software or firmware issues in the IPC or BCM
• Faulty CAN bus communication
• Issues with other modules on the network

Common Troubleshooting Steps

When dealing with the OBD-II code U1135, which indicates “Lost Communication with Instrument Panel Cluster (IPC) Control Module,” there are several common troubleshooting steps you can follow to diagnose and potentially resolve the issue. Here’s a structured approach:

• Check for Additional Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue.
• Inspect the Wiring and Connectors: **Visual Inspection: Check the wiring harness and connectors related to the IPC for any signs of damage, corrosion, or loose connections.
• **Connector Pins: Ensure that the pins in the connectors are not bent, corroded, or damaged.
• Check Power and Ground: Verify that the IPC is receiving the correct voltage and ground. Use a multimeter to check for proper voltage at the IPC connector.
• Check the ground connections to ensure they are secure and free of corrosion.
• Inspect the IPC Module: If possible, remove the IPC module and inspect it for physical damage or signs of water intrusion.
• If the IPC is removable, consider testing it in another vehicle (if available) to confirm its functionality.
• Check for Communication Issues: Use a scan tool to check if the IPC is communicating with other modules in the vehicle. If other modules are also not communicating, the issue may be with the communication bus (CAN bus).
• Inspect the CAN bus wiring for shorts, opens, or interference.
• Test the Vehicle’s Battery and Charging System: A weak battery or poor charging system can cause communication issues. Ensure the battery is fully charged and the alternator is functioning properly.
• Look for Software Updates: Check if there are any software updates available for the IPC or the vehicle’s control modules. Sometimes, manufacturers release updates to fix communication issues.
• Perform a Hard Reset: Disconnect the vehicle’s battery for a few minutes to reset the modules. Reconnect and see if the code reappears.
• Check for Aftermarket Modifications: If any aftermarket accessories or modifications have been made to the vehicle, they could interfere with the IPC communication. Temporarily remove or disconnect them to see if the issue resolves.
• Consult Technical Service Bulletins (TSBs): Look for any TSBs related to the IPC or communication issues for your specific vehicle make and model. Manufacturers may have documented common issues and solutions.1
• Professional Diagnosis: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis. They may have specialized tools and knowledge to address complex communication issues. By following these steps, you should be able to identify the root cause of the U1135 code and take appropriate action to resolve it.