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Solved - Strange parking sensor problem
- bladeowner
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- Location: Yorkshireman in High Wycombe
Solved - Strange parking sensor problem
Hi, My parking sensors have stopped working properly when the engine is running. Although sometimes the gong squawks a little like it's trying to beep. When I just turn on the ignition but not start the car they work fine. Each sensor is 'ticking' whether the engine is running or not and works perfectly with an obstacle - if I don't start the car. I have tried another gong and it's just the same. Any ideas anybody? I'm baffled.
Last edited by bladeowner on Thu Nov 09, 2017 2:50 pm, edited 1 time in total.
2004 Sapphire Black 2.5 SE Z4 SMG
- Stuart Truman
- Lifer
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Strange parking sensor problem
Weird. If you think about the difference, the only thing is that the alternator is running. Do you get interference on the radio? I'm wondering if a suppressor is failing and you're getting interference on the 12v line.
The battery heading towards end of life can cause all manner of strange things, but this doesn't sound like that type of symptom
The battery heading towards end of life can cause all manner of strange things, but this doesn't sound like that type of symptom
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Z4M Roadster, Imola Red, with Stubby and Intravee II. Low Miles per Gallon, High Smiles per Gallon
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Z4M Roadster, Imola Red, with Stubby and Intravee II. Low Miles per Gallon, High Smiles per Gallon
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- bladeowner
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- Joined: Wed Apr 18, 2012 7:40 pm
- Location: Yorkshireman in High Wycombe
Re: Strange parking sensor problem
Hi, No there doesn't appear to be any interference on the radio. I have an oscilloscope but no probe at the moment and so I could check when I get one. I am thinking that maybe the PDC controller also gets a signal to say the engine is running?? - and this is a bad connection. As I mentioned, it seems like it tries to work. The reversing light comes on in both scenarios. Is the same switch used for PDC and the reversing light? Thanks.
2004 Sapphire Black 2.5 SE Z4 SMG
- Stuart Truman
- Lifer
- Posts: 13039
- Joined: Wed Jul 27, 2011 10:59 pm
- Location: The Cotswolds
Strange parking sensor problem
That I don't know, but I'd suggest a dirty switch would give you the same symptom whether or not the engine is running.bladeowner wrote:Hi, No there doesn't appear to be any interference on the radio. I have an oscilloscope but no probe at the moment and so I could check when I get one. I am thinking that maybe the PDC controller also gets a signal to say the engine is running?? - and this is a bad connection. As I mentioned, it seems like it tries to work. The reversing light comes on in both scenarios. Is the same switch used for PDC and the reversing light? Thanks.
I'd probably test the battery (as that's a simple thing to do if you have a meter) and then check the 12v line. You could also check for noise on the earth when the engine is running as that would also bugger up the voltages.
After that it's probably worth plugging into diagnostics for any errors. If you've got iffy voltages flying around there's a good chance something else will get upset.
Another giveaway is the rev counter "bouncing" randomly (the needle randomly skips up and immediately back to a correct reading with no change in revs)
You have an oscilloscope! Good man
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Z4M Roadster, Imola Red, with Stubby and Intravee II. Low Miles per Gallon, High Smiles per Gallon
Previously Alpina Roadster S #69 Alpina Blue
Z4M Roadster, Imola Red, with Stubby and Intravee II. Low Miles per Gallon, High Smiles per Gallon
Previously Alpina Roadster S #69 Alpina Blue
- bladeowner
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Re: Strange parking sensor problem
Thanks, will check the 12V out.
2004 Sapphire Black 2.5 SE Z4 SMG
- bladeowner
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Re: Strange parking sensor problem
I checked the 12v to the gong and the voltage is pulsing when the engine is running. Other 12 V lines are fine as far as I can tell. I left the scope on it and started pulling fuses to see if another unit was causing it. When I pulled fuse 23 the pulsing stopped. F23 is a 5A fuse for various lighting circuits. The PDC worked ok then for a few seconds but the dashboard warning lights don't work with the fuse pulled and so this stopped it.
Obviously the gong doesn't like this pulsed DC and so for the interim I've soldered a 220uf capacitor inside the gong across the supply rail to smooth the dc- all now working.
So I still need to find out why this rail is pulsing. Anybody know a link for decent wiring drawings of the car?
Obviously the gong doesn't like this pulsed DC and so for the interim I've soldered a 220uf capacitor inside the gong across the supply rail to smooth the dc- all now working.
So I still need to find out why this rail is pulsing. Anybody know a link for decent wiring drawings of the car?
2004 Sapphire Black 2.5 SE Z4 SMG
- Stuart Truman
- Lifer
- Posts: 13039
- Joined: Wed Jul 27, 2011 10:59 pm
- Location: The Cotswolds
Strange parking sensor problem
http://spaghetticoder.org/ has them.
Add yourself to the Z4 Map HERE! Instructions HERE!
Z4M Roadster, Imola Red, with Stubby and Intravee II. Low Miles per Gallon, High Smiles per Gallon
Previously Alpina Roadster S #69 Alpina Blue
Z4M Roadster, Imola Red, with Stubby and Intravee II. Low Miles per Gallon, High Smiles per Gallon
Previously Alpina Roadster S #69 Alpina Blue
- bladeowner
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- Ducklakeview
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Strange parking sensor problem
Have you replaced any bulbs with LED's?bladeowner wrote: ↑Thu Aug 16, 2012 6:19 pm I checked the 12v to the gong and the voltage is pulsing when the engine is running. Other 12 V lines are fine as far as I can tell. I left the scope on it and started pulling fuses to see if another unit was causing it. When I pulled fuse 23 the pulsing stopped. F23 is a 5A fuse for various lighting circuits. The PDC worked ok then for a few seconds but the dashboard warning lights don't work with the fuse pulled and so this stopped it.
Obviously the gong doesn't like this pulsed DC and so for the interim I've soldered a 220uf capacitor inside the gong across the supply rail to smooth the dc- all now working.
So I still need to find out why this rail is pulsing. Anybody know a link for decent wiring drawings of the car?
Mike
- ph001
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Strange parking sensor problem
I wonder if he still cares 5 yrs on!
- Ducklakeview
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- ph001
- Lifer
- Posts: 3870
- Joined: Mon Oct 31, 2016 5:53 pm
- Location: N. Yorkshire.
Strange parking sensor problem
Wow!! LOL
- bladeowner
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- Joined: Wed Apr 18, 2012 7:40 pm
- Location: Yorkshireman in High Wycombe
Strange parking sensor problem
2004 Sapphire Black 2.5 SE Z4 SMG
- bladeowner
- Senior Member
- Posts: 1453
- Joined: Wed Apr 18, 2012 7:40 pm
- Location: Yorkshireman in High Wycombe
Strange parking sensor problem
I did wonder about that myself but only fitted a few leds after the problem started. Anyway, the only leds that are lit are the sidelights as drl and they are on when the ignition is on but engine not running as well and it doesn't cause an issue then.Ducklakeview wrote: ↑Wed Sep 20, 2017 2:39 pmHave you replaced any bulbs with LED's?bladeowner wrote: ↑Thu Aug 16, 2012 6:19 pm I checked the 12v to the gong and the voltage is pulsing when the engine is running. Other 12 V lines are fine as far as I can tell. I left the scope on it and started pulling fuses to see if another unit was causing it. When I pulled fuse 23 the pulsing stopped. F23 is a 5A fuse for various lighting circuits. The PDC worked ok then for a few seconds but the dashboard warning lights don't work with the fuse pulled and so this stopped it.
Obviously the gong doesn't like this pulsed DC and so for the interim I've soldered a 220uf capacitor inside the gong across the supply rail to smooth the dc- all now working.
So I still need to find out why this rail is pulsing. Anybody know a link for decent wiring drawings of the car?
Mike
I ran the engine with alternator disconnected and the problem stopped and so it does appear to be the alternator.
2004 Sapphire Black 2.5 SE Z4 SMG
- Ducklakeview
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Strange parking sensor problem
Ok - I'll let you know when I've changed the rectifier and post before and after scope traces.bladeowner wrote: ↑Wed Sep 20, 2017 3:22 pmI did wonder about that myself but only fitted a few leds after the problem started. Anyway, the only leds that are lit are the sidelights as drl and they are on when the ignition is on but engine not running as well and it doesn't cause an issue then.Ducklakeview wrote: ↑Wed Sep 20, 2017 2:39 pmHave you replaced any bulbs with LED's?bladeowner wrote: ↑Thu Aug 16, 2012 6:19 pm I checked the 12v to the gong and the voltage is pulsing when the engine is running. Other 12 V lines are fine as far as I can tell. I left the scope on it and started pulling fuses to see if another unit was causing it. When I pulled fuse 23 the pulsing stopped. F23 is a 5A fuse for various lighting circuits. The PDC worked ok then for a few seconds but the dashboard warning lights don't work with the fuse pulled and so this stopped it.
Obviously the gong doesn't like this pulsed DC and so for the interim I've soldered a 220uf capacitor inside the gong across the supply rail to smooth the dc- all now working.
So I still need to find out why this rail is pulsing. Anybody know a link for decent wiring drawings of the car?
Mike
I ran the engine with alternator disconnected and the problem stopped and so it does appear to be the alternator.
Mike