Rear PDC wiring harness corrosion

Breach · 12-18-2022, 10:11 AM

A couple of years ago, my rear left outermost PDC sensor intermittently started to throw errors and then the car lost connection completely (ISTA says no signal to that sensor and the car disables PDC completely).

Not a major issue, as I don't really care about PDC, but I have to manually confirm the error every time the cameras switch on or I put the car in reverse.

Initially, I thought it was a bad sensor, replaced it - no go. Then at the advice of my indy I replaced the JBBF module - same story. So, I'm 99% sure it's a wiring loom issue. I've examined the harness behind the bumper and also the part behind the right trunk space (where the power distribution box is) - nothing obvious. Next step of course would be to get my multimeter out and start checking foot by foot (or meter by meter), but these wires go all the way from the rear bumper to the JBBF module under the glove box, which means quite a bit of work actually. So, just in case anyone has had this issue before, any ideas where are the most likely failure points?

Thanks

Hoa · 12-19-2022, 06:05 AM

Most likely fail points will be outside of the vehicle at the plug. I have this harness from the rubber gorument to the sensor. PM me if you are interested.

Stephenhirst1 · 06-12-2023, 04:35 PM

Quote:

Originally Posted by Breach

A couple of years ago, my rear left outermost PDC sensor intermittently started to throw errors and then the car lost connection completely (ISTA says no signal to that sensor and the car disables PDC completely).

Not a major issue, as I don't really care about PDC, but I have to manually confirm the error every time the cameras switch on or I put the car in reverse.

Initially, I thought it was a bad sensor, replaced it - no go. Then at the advice of my indy I replaced the JBBF module - same story. So, I'm 99% sure it's a wiring loom issue. I've examined the harness behind the bumper and also the part behind the right trunk space (where the power distribution box is) - nothing obvious. Next step of course would be to get my multimeter out and start checking foot by foot (or meter by meter), but these wires go all the way from the rear bumper to the JBBF module under the glove box, which means quite a bit of work actually. So, just in case anyone has had this issue before, any ideas where are the most likely failure points?

Thanks

Did you resolve this issue?

Breach · 06-12-2023, 05:00 PM

Not yet. Got the wiring harness (only for the PDC) and some black silicone as it doesn't seem that BMW sell the firewall grommet separately. Routing to the JBBF seems tedious but straightforward. Still have to do the job though:-)

Breach · 02-11-2024, 01:23 PM

Well, 5 years later, but it's finally fixed. The breakage was in the harness before the firewall grommet. One wire was completely cut somehow, under the tape. No idea what happened, wasn't corrosion. I suspect it may have been damaged when the dealer changed my rear bumper. I bought a pdc repair wire, cut it and spliced all 12 wires, shrink wrap + automotive tape. Hope it lasts.

12-18-2022, 10:11 AM	#1
Breach First Lieutenant 80 Rep 373 Posts Drives: F10 520dA M Sport Join Date: Jun 2010 Location: EU iTrader: (0)	Rear PDC wiring harness corrosion - where to look? A couple of years ago, my rear left outermost PDC sensor intermittently started to throw errors and then the car lost connection completely (ISTA says no signal to that sensor and the car disables PDC completely). Not a major issue, as I don't really care about PDC, but I have to manually confirm the error every time the cameras switch on or I put the car in reverse. Initially, I thought it was a bad sensor, replaced it - no go. Then at the advice of my indy I replaced the JBBF module - same story. So, I'm 99% sure it's a wiring loom issue. I've examined the harness behind the bumper and also the part behind the right trunk space (where the power distribution box is) - nothing obvious. Next step of course would be to get my multimeter out and start checking foot by foot (or meter by meter), but these wires go all the way from the rear bumper to the JBBF module under the glove box, which means quite a bit of work actually. So, just in case anyone has had this issue before, any ideas where are the most likely failure points? Thanks
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12-19-2022, 06:05 AM	#2
Hoa Major 513 Rep 1,356 Posts Drives: BMW Join Date: May 2010 Location: GA iTrader: (9)	Most likely fail points will be outside of the vehicle at the plug. I have this harness from the rubber gorument to the sensor. PM me if you are interested.
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06-12-2023, 05:00 PM	#4
Breach First Lieutenant 80 Rep 373 Posts Drives: F10 520dA M Sport Join Date: Jun 2010 Location: EU iTrader: (0)	Not yet. Got the wiring harness (only for the PDC) and some black silicone as it doesn't seem that BMW sell the firewall grommet separately. Routing to the JBBF seems tedious but straightforward. Still have to do the job though:-)
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02-11-2024, 01:23 PM	#5
Breach First Lieutenant 80 Rep 373 Posts Drives: F10 520dA M Sport Join Date: Jun 2010 Location: EU iTrader: (0)	Well, 5 years later, but it's finally fixed. The breakage was in the harness before the firewall grommet. One wire was completely cut somehow, under the tape. No idea what happened, wasn't corrosion. I suspect it may have been damaged when the dealer changed my rear bumper. I bought a pdc repair wire, cut it and spliced all 12 wires, shrink wrap + automotive tape. Hope it lasts.
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