One of my rear parking sensors started sticking on. Pretty clear from the graphic on the screen that it was rear right. So, I bought a replacement that was identical and a perfect fit. Swapped it (easy enough) and got an error and no PDC working at all. I assumed it meant the one I bought was wrong, so I put the original one back in, but the error now persists and I have no PDC! Seems odd, as it was working before (albeit sticking on)!? Not sure what to do now....

Edited 30 March, 20251 yr by djg303

I've seen this a couple of times before. I know this sounds like a strange fix, but It's worth making sure the battery capacity is good. Problematic batteries which are failing will trigger this issue. Get a CCA test done on your car battery and if it's 20% below capacity, then it's dying and needs replacing (and coding in)

+1 Check battery

If still not working may be the connector/cable

Thanks for the advice. I did a basic battery test using a multimeter - capacity is good and not dropping below 10v on cranking. I visually checked the wiring across all 4 rear sensors, and it all looks undamaged. Not sure how to test it though.

I've managed to get everything back to the original state. I now have the original sensor back in; no error on the screen, but the sensor sticks on when in reverse (I.e. as though that one sensor is really close to something).

Might it be that the replacement sensor I bought (despite looking identical and being a perfect fit) is wrong? It's one of these: https://www.amazon.co.uk/dp/B0CNGKMN12?ref=ppx_yo2ov_dt_b_fed_asin_title

Thanks again.

On 02/04/2025 at 16:08, djg303 said:

Thanks for the advice. I did a basic battery test using a multimeter - capacity is good and not dropping below 10v on cranking. I visually checked the wiring across all 4 rear sensors, and it all looks undamaged. Not sure how to test it though.

I've managed to get everything back to the original state. I now have the original sensor back in; no error on the screen, but the sensor sticks on when in reverse (I.e. as though that one sensor is really close to something).

Might it be that the replacement sensor I bought (despite looking identical and being a perfect fit) is wrong? It's one of these: https://www.amazon.co.uk/dp/B0CNGKMN12?ref=ppx_yo2ov_dt_b_fed_asin_title

Thanks again.

I suppose you put a new sensor for now. Is everythings good ?

On 02/04/2025 at 15:08, djg303 said:

Thanks for the advice. I did a basic battery test using a multimeter - capacity is good and not dropping below 10v on cranking

humm, that not really how you do a CCA (Cold Cranking Amps) test on a battery. The whole concept is that the rear parking sensors are on the end of a very long CANBUS network stretching out across the car. If the alternator cannot keep up with the poor battery, it will cause spikes in the voltage and this will upset the CANBUS network itself. Get yourself a CCA tester from ebay and do a proper test. Voltage is not always a good indicator of a problem battery.

4 minutes ago, varaderoguy said:

humm, that not really how you do a CCA (Cold Cranking Amps) test on a battery. The whole concept is that the rear parking sensors are on the end of a very long CANBUS network stretching out across the car. If the alternator cannot keep up with the poor battery, it will cause spikes in the voltage and this will upset the CANBUS network itself. Get yourself a CCA tester from ebay and do a proper test. Voltage is not always a good indicator of a problem battery.

While not perfect, testing the voltage at the battery terminals while cranking the engine on the starter motor is a reasonable test of battery health.

A high-rate discharge is still the best test, but a dedicated battery tester is a relatively inexpensive and extremely useful tool to have.