E46 Parking Sensors - not your usual problem
Discussion
Ok so I know there's a gazillion threads on E46 parking sensor issues, however this one is different to the usual 'check which sensor is not clicking and replace it' thread.
When I start the car in the morning, the rear PDC works perfectly. No problems whatsoever. However when I arrive at work (only 6 miles later), upon selecting reverse it will beep rapidly for 2 or 3 beeps, then go to a consistent tone the same as when you're very close to an object. I've gotten out of the car and checked all 4 sensors, and they're all merrily clicking away.
If I turn the car off and leave it, even for only 5 minutes, then start her up again and try again, they work perfectly. I thought it may be a heat soak issue, however they were working ok in the summer when the ambient was easily 20C warmer than current.
Any ideas? Has anyone else experienced this exact same issue?
When I start the car in the morning, the rear PDC works perfectly. No problems whatsoever. However when I arrive at work (only 6 miles later), upon selecting reverse it will beep rapidly for 2 or 3 beeps, then go to a consistent tone the same as when you're very close to an object. I've gotten out of the car and checked all 4 sensors, and they're all merrily clicking away.
If I turn the car off and leave it, even for only 5 minutes, then start her up again and try again, they work perfectly. I thought it may be a heat soak issue, however they were working ok in the summer when the ambient was easily 20C warmer than current.
Any ideas? Has anyone else experienced this exact same issue?
Thanks Fox - I guess it's just trying to find which damn sensor!
As an update, I've been trying all sorts of things to see if I can make the fault repeatable, but to no avail. The one thing it always does it work ok from cold 100% everytime. However when the car's warm, most of the time it goes into the constant tone routine, however there have been the odd times when it's been ok.
I've also tried cleaning the sensors when they're playing up, then immediately trying it again and the results are again variable.
I guess I'll just have to have the rear trim off (saloon), check the wiring and if that fails, to find anything, buy a single replacement sensor and start trial and error of placing it in each of the 4 available channels and seeing what difference it makes.
BMW electrics...Grrrrrrr
As an update, I've been trying all sorts of things to see if I can make the fault repeatable, but to no avail. The one thing it always does it work ok from cold 100% everytime. However when the car's warm, most of the time it goes into the constant tone routine, however there have been the odd times when it's been ok.
I've also tried cleaning the sensors when they're playing up, then immediately trying it again and the results are again variable.
I guess I'll just have to have the rear trim off (saloon), check the wiring and if that fails, to find anything, buy a single replacement sensor and start trial and error of placing it in each of the 4 available channels and seeing what difference it makes.
BMW electrics...Grrrrrrr
Ok update on this.
In spite of all my 4 sensors clicking away, yet still getting the constant tone from the PDC, I've taken the step to replace all 4 sensors.
Rather than blowing circa £400 on BMW parts, I purchased 4 x brand new LR Discovery sensors for 33% of the cost (as per the thread here). The parts themselves are almost identical, and both are made by Valeo.
So I replaced them on Saturday, and have been driving every day since. And, fingers crossed and touch wood etc, they've been working perfectly ever since. I've even jet washed the car to see if I could get them to 'fail', but they've worked perfectly each and every time. So far, I'm a happy chappy! I will update this thread again if anything changes.
Cheers.
In spite of all my 4 sensors clicking away, yet still getting the constant tone from the PDC, I've taken the step to replace all 4 sensors.
Rather than blowing circa £400 on BMW parts, I purchased 4 x brand new LR Discovery sensors for 33% of the cost (as per the thread here). The parts themselves are almost identical, and both are made by Valeo.
So I replaced them on Saturday, and have been driving every day since. And, fingers crossed and touch wood etc, they've been working perfectly ever since. I've even jet washed the car to see if I could get them to 'fail', but they've worked perfectly each and every time. So far, I'm a happy chappy! I will update this thread again if anything changes.
Cheers.
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