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2021 Q7 Keyless Entry/Start Intermittent - B1000 Code

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Christine P. · rep 0 · May 22, 4:26 AM · 1 replies · solved · Question

Vehicle: 2021 Audi Q7 Prestige

Hi everyone,

I'm having some frustrating issues with the keyless entry and push-button start system on my 2021 Audi Q7 Prestige. Lately, the keyless entry (Advanced Key) has been very intermittent. Sometimes it works perfectly, and I can just grab the door handle to unlock, but other times I have to manually press the unlock button on the key fob. Similarly, the push-button start sometimes requires me to place the key in the designated holder in the center console, even though it should work just by being in the cabin.

I've already replaced the battery in both key fobs, but that hasn't made any difference. I ran a quick OBD scan and got a generic B1000 code, which usually points to a 'Control Module Fault'.

Could this be an issue with the comfort control module, or perhaps one of the keyless entry antennas? Has anyone else experienced similar problems with their Q7 or other Audi models? Any advice on what to check would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

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

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ClearTheCode admin answer:

The B1000 code (Control Module Fault) is a very general code, but combined with your keyless entry and start issues, it strongly suggests a problem within the Advanced Key system, which relies on several interconnected electronic components.

Potential Causes:

  1. Faulty Comfort Control Module (CCM): The CCM (also known as the J393 or BCM2) is the central brain for keyless entry, central locking, and other convenience features. A fault within this module can cause intermittent or complete failure of these systems.
  2. Keyless Entry Antennas: The vehicle has multiple antennas (e.g., in door handles, trunk, interior) that detect the key fob's presence. If one or more of these antennas are faulty, damaged, or have wiring issues, the system won't reliably detect the key.
  3. Wiring/Connection Issues: Corroded, loose, or damaged wiring harnesses connecting the CCM to the antennas, door handles, or start button can cause intermittent communication or power supply problems.
  4. Door Handle Sensors: The touch sensors in the door handles themselves can fail, preventing keyless unlocking.
  5. Interference: While less common, strong electromagnetic interference in certain areas could temporarily disrupt the keyless system.

Troubleshooting Steps:

  1. Check Fuses: Locate and inspect all fuses related to the central locking, comfort system, and keyless entry. A blown or loose fuse can cause intermittent issues.
  2. Inspect Door Handles: Visually inspect the door handles for any physical damage or signs of wear that might affect the integrated sensors.
  3. Test Both Key Fobs: Even though you replaced batteries, ensure both key fobs exhibit the same intermittent behavior. This helps rule out a faulty fob itself.

When to See a Shop:

  • If the issue persists after checking fuses and confirming both key fobs are functioning correctly.
  • Given the B1000 code and the complexity of the Advanced Key system, professional diagnosis is highly recommended. Audi-specific diagnostic tools (like VCDS or ODIS) are crucial for this. They can:
    • Read specific fault codes from the Comfort Control Module (which a generic OBD-II scanner might not access).
    • Perform function tests on individual antennas and sensors.
    • Check live data to see if the key fob is being detected by specific antennas.
    • Identify if the CCM itself needs a software update or replacement. This will help pinpoint whether it's a module, antenna, or wiring issue.
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