U2336 – Control Module Communication Bus Fault

The ODBII code U2336: Control Module Communication Bus Fault indicates a communication issue between control modules in a vehicle, suggesting that one or more modules are not properly communicating over the vehicle’s data bus.

The severity of ODBII code U2336 is moderate to severe.

Common Causes For: U2335 U2335: Hybrid Powertrain Control Module Communication Error

• Faulty control module
• Damaged wiring or connectors
• Poor ground connections
• Short circuits in the communication bus
• Interference from aftermarket devices
• Corroded terminals
• Software issues or bugs in the control module
• Low battery voltage or power supply issues

Common misdiagnosis for U2336 U2336: Control Module Communication Bus Fault

• Faulty control module
• Wiring issues
• Poor ground connections
• Corrupted software/firmware
• Faulty sensors
• Battery or power supply problems
• Intermittent connection issues
• Other communication bus faults (e.g., CAN bus issues)

Common Troubleshooting Steps

The OBD-II code U2336 indicates a “Control Module Communication Bus Fault.” This code typically points to a problem with the communication between various control modules in the vehicle. Here are some common troubleshooting steps to diagnose and resolve this issue:

• 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 Wiring and Connectors: Visually inspect the wiring and connectors associated with the control modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harnesses that connect the affected modules.
• Check for Short Circuits or Open Circuits: Use a multimeter to check for continuity in the communication lines. Look for any short circuits or open circuits that could disrupt communication.
• Test Control Modules: If possible, test the affected control modules individually. This may involve swapping them with known good modules to see if the problem persists.
• Ensure that the modules are receiving proper power and ground.
• Inspect the CAN Bus: If your vehicle uses a Controller Area Network (CAN) bus, check the bus for proper voltage levels. The typical voltage levels should be around 2.5V to 3.5V for CAN High and CAN Low.
• Use an oscilloscope if available to check for proper signal waveforms on the CAN lines.
• Check for Interference: Look for any aftermarket devices or modifications that may interfere with the communication bus. This includes alarms, stereo systems, or other electronic devices.
• Update or Reprogram Modules: In some cases, a software update or reprogramming of the control modules may be necessary. Check with the manufacturer for any available updates.
• Clear Codes and Test Drive: After performing any repairs or adjustments, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual: Refer to the vehicle’s service manual for specific diagnostic procedures related to the U2336 code and the communication bus system.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with your specific vehicle make and model. By following these steps, you should be able to identify and resolve the underlying issue causing the U2336 code.