U0145 — Data bus: body control module (8CM) E – no communication #

Note: The code label may vary depending on the vehicle manufacturer.

• U0145 – Lost Communication With Body Control Module (BCM) (Ford, GM, Chrysler)
• U0145 – No Communication With BCM (Volkswagen, Audi, BMW)
• U0145 – CAN Communication Error: BCM (Peugeot, Citroën, Nissan)
• U0145 – Body Control Module Communication Failure (Hyundai, Kia, Honda)

Summary of code U0145 #

The U0145 diagnostic trouble code (DTC) is triggered when the vehicle’s main computer, often called the powertrain control module (PCM), cannot communicate with the body control module (BCM) via the vehicle’s data bus system, typically the Controller Area Network (CAN) bus. The BCM is responsible for controlling and coordinating non-engine-related functions, such as lighting, windows, security, and more. A loss of communication may impact several comfort and safety features, sometimes resulting in erratic or non-functional systems. While this is primarily an electrical communication issue, it can sometimes point to larger wiring or module failures. The trouble code is standardized under OBD-II/EOBD systems but may have specific nuances depending on the OEM (Original Equipment Manufacturer).

Frequent Symptoms for code U0145 #

When U0145 appears, the effects can range from minor annoyances to significant disruptions of vehicle comfort features. The symptoms depend on which BCM functions are affected and how other modules respond to the loss of communication. Look out for these possible signs:

• Malfunction indicator light (MIL) or check engine light illuminated
• Non-functioning or erratic power windows, locks, or mirrors
• Inoperative or random behavior of interior/exterior lighting
• Problems with alarm or immobilizer system
• Issues with remote keyless entry or push-button start
• Loss of communication codes stored in other modules
• Occasional battery drain or electrical glitches

Most Likely Causes for code U0145 #

The root causes of a U0145 code often relate to wiring, module power supply, or the data communication network itself. Some issues are more common than others. Here’s an ordered breakdown:

1. Faulty Body Control Module (BCM): Internal failure or module crash
2. Open or shorted CAN bus wiring: Damaged, corroded, or disconnected wires between BCM and other modules
3. Poor electrical ground or power supply to BCM: Loose connections, blown fuses, or relay issues
4. Connector issues: Loose, dirty, or corroded BCM connectors
5. Intermittent CAN bus signal interference: Aftermarket equipment or harness damage
6. Fault in other networked modules: Rarely, a different module can disrupt communication

Step-by-Step Diagnosis for code U0145 #

A systematic approach is essential for pinpointing the exact cause of a U0145 code. Avoid jumping to conclusions—methodically rule out each possibility:

• 1. Scan for additional DTCs: Use a professional scan tool to check for related codes in all vehicle modules.
• 2. Check BCM operation: Attempt to communicate directly with the BCM using scan tool functions.
• 3. Inspect fuses and relays: Verify that all power and ground circuits for the BCM are intact.
• 4. Visually inspect wiring and connectors: Look for signs of corrosion, damage, or loose connections at the BCM and along the CAN bus harness.
• 5. Perform continuity and resistance checks: Use a multimeter to test CAN high and low wires for shorts or open circuits.
• 6. Isolate the BCM: Disconnect the BCM and check if the rest of the network communicates normally, indicating a possible module fault.
• 7. Consult OEM service information: Refer to wiring diagrams and technical bulletins specific to your vehicle.

Possible Repairs for code U0145 #

Repairs should directly address the verified fault. Avoid replacing expensive modules unless testing confirms failure. Common solutions include:

• Repair or replace damaged CAN bus wiring or connectors
• Clean or tighten BCM connector pins and sockets
• Replace blown fuses or faulty relays supplying BCM power/ground
• Update or reprogram BCM software (if an OEM update is available)
• Replace the BCM (only after all other causes are ruled out and OEM testing procedures confirm failure)
• Remove or properly integrate aftermarket devices interfering with the CAN network

Is it safe to drive with code U0145? #

It depends, but caution is advised. In most cases, a U0145 code will not affect the engine or drivetrain operation. However, loss of body control functions means you may be without power windows, lighting, or even security features. For example, if your lights fail at night or your doors cannot lock, this can create a safety risk. If you notice any critical features not working, limit driving and repair the issue as soon as possible. Always follow your OEM’s recommendations.

Vehicles Most Commonly Affected by code U0145 #

U0145 is a generic OBD-II code found across many brands, but some models are more prone to BCM communication issues due to design or historical trends. Notably affected vehicles include:

• Chevrolet Silverado, GMC Sierra (2014–present)
• Ford F-150, Fusion, Escape (2013–present)
• Chrysler/Dodge/Jeep models (2010–present)
• Volkswagen Golf, Passat, Jetta (2015–present)
• Hyundai Sonata, Kia Optima (2012–present)
• Nissan Altima, Rogue (2013–present)
• Peugeot 308, Citroën C4 (2011–present)

Common Mistakes & Best Practices for code U0145 #

Misdiagnosis of U0145 often leads to unnecessary parts replacement or missed root causes. To avoid costly errors, keep these tips in mind:

• Do not replace the BCM without testing wiring, power, and grounds first
• Check for water intrusion or corrosion near the BCM (a frequent culprit)
• Always disconnect the battery before unplugging control modules
• Use OEM wiring diagrams, not generic ones, for accurate troubleshooting
• Clear all codes after repair and recheck system operation before returning the vehicle to service

Quick FAQ for code U0145 #

Still have questions? Here are fast answers to the most common concerns:

• Q: Will U0145 cause my car to stall or not start?
  A: Generally, no—the engine and drivetrain usually remain operational, but security systems linked to the BCM may prevent starting on some vehicles.
• Q: Can an aftermarket alarm or stereo trigger U0145?
  A: Yes, improperly installed aftermarket electronics can interfere with the CAN bus, causing communication errors like U0145.