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2022 A6 Parking Sensors & Rear Camera Intermittent - U0140 Code

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Mark S. · rep 0 · May 22, 4:26 AM · 1 replies · solved · Question

Vehicle: 2022 Audi A6 S line

Hello Audi community,

I'm experiencing some really annoying intermittent issues with the parking assist system in my 2022 Audi A6 S line. The front and rear parking sensors will sometimes just stop working, and I get a warning message on the MMI screen. Other times, when I put the car in reverse, the rear camera feed is just a black screen, or it flickers before going black.

It's not consistent; sometimes everything works perfectly, and then out of nowhere, it acts up. I've checked for any obvious obstructions on the sensors, but they seem clear. I ran a scan with my OBD-II tool and got a U0140 code, which indicates 'Lost Communication With Body Control Module'.

Could this be a wiring issue, or perhaps a problem with the parking assist control module itself? Any insights or similar experiences with newer A6 models would be helpful. Thanks!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:26 AM

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ClearTheCode admin answer:

The U0140 code (Lost Communication With Body Control Module) is a critical clue for your intermittent parking sensor and rear camera issues. This code suggests a communication breakdown on the CAN bus network, which is how various control modules in your Audi communicate with each other, including the parking assist module and the Body Control Module (BCM).

Potential Causes:

  1. Wiring Harness Damage: Damaged, corroded, or loose wiring in the CAN bus network, especially to the parking assist control module or the camera, can cause intermittent communication loss. This is common in areas exposed to moisture or vibration.
  2. Faulty Parking Assist Control Module: The module itself could be failing internally, leading to intermittent operation and communication errors.
  3. Faulty Rear View Camera Module: The camera unit or its integrated control module might be failing, causing a black screen and potentially disrupting the communication network.
  4. Grounding Issues: Poor grounding for any of the involved modules can lead to erratic electrical behavior and communication problems.
  5. Software Glitch: Less common for hardware-like symptoms, but a corrupted software state in the BCM or parking assist module could cause communication issues.

Troubleshooting Steps:

  1. Visual Inspection: Carefully inspect the wiring harnesses leading to the parking sensors, the rear camera, and the parking assist control module (often located in the trunk or under the dashboard) for any signs of damage, fraying, or loose connections.
  2. Check Fuses: Verify that all fuses related to the parking assist system and the BCM are intact and properly seated.
  3. Module Reseat: If accessible, try disconnecting and reconnecting the connectors to the parking assist control module and the rear camera module to ensure a good connection.

When to See a Shop:

  • If the visual inspection and fuse checks don't resolve the issue.
  • If the problem is persistent and impacts safety features.
  • A professional diagnostic scan with Audi-specific tools (VCDS/ODIS) is highly recommended. These tools can perform module-specific tests, read live data from the CAN bus, and identify which specific module is losing communication or if there's a fault within the module itself. This is crucial for diagnosing complex network communication faults like U0140, which often require tracing wiring diagrams and advanced electrical testing.
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