e46 b3s coupe rear pdc sensor replacement top tips

[rc944]

So ticking off list of jobs with the final one being the replacement of a dead sensor. you can check the sensors without diag equipment by releasing handbrake and sticking box into reverse. pop your ear over the sensors. if they make a faint ticking sound they are working. in my case, my far left sensor was dead and had been for months

i had never removed the bumper and heard it was a bit tricky. heres what i did loosely guided by haynes

- get the car onto ramps
- release x2 fixings in wheel arch using 8mm spanner and plastic pry tools
- release 2x torx 50 bolts. note that i had to use a long torx key and a t bar with 13mm socket to give me leverage
- wiggle free the bumper being careful to prise the bumper lugs free from the retaining clip in wheel arch liner
- there is an ally alpina specific bracket that affixes the bumper to chassis on the torx bolt closest to exhaust - it will become bent during the removal of the bumper but easily straightened out with vice
- cleaned the whole lot and degrease and apply wd40 to painted parts
- tardis on the exhaust tips as you get access to the rear top of each tip
- contact cleaner in all pdc adaptors
- test all sensors whilst in situ but with bumper not yet attached

those white plastic steps are very useful as extra hands when it comes to getting the bumper on and off

I was pleased to see that the bumper was the original one and the back and sides looked tidy so reversal of the above to get you back on the road. whilst your down there check rear output shaft seals, shocks, arb and bushes etc for good measure

genuine colour coded sensors cost about £30 from ebay vs a lot more brand new

good luck

[Fast3000]

Nice work RC. Good to see the method. Also generally clean behind the bumper too

[Rav]

Great work RC944 - I had this with my saloon B3 recently. I managed to get the sensor replaced without removing the rear bumper, but did struggle and lost lots of skin on my wrists and hands!

I wish i had taken the bumper off to clean behind here.

I noted that some of the sensors have a lozenge style pattern on them and my car came with a circular pattern on the face of the sensor.
I have a mix, which bugs me, but i guess no one else would ever notice.