mcai8sh4 Posted May 12, 2008 Share Posted May 12, 2008 Ok, I know I've only just joined, but any help with this little irriataion would be appreciated. I have an 04 plate 350, bought second hand, alls worked well for over 6 months. Suddenly my parking distance indicator 'beeps' have stopped. I used to get the annoying but useful single beep when engaging reverse gear, followed by more beeps the closer I got to a wall/car/gate/small child... Now I get nothing, it just stopped working one day. The reverse light still works ok (so I assume the switch in the gearbox & fuse are ok). I've found a black box stuck inside the boot with the following writing on : RPS20 4M0168N1A There are 4 connectors (one per sensor?), a 3 pin connector (power?) and another 2 wires labled 'buz' (buzzer for the beeping noise). My plan is to check for power when reverse is selected, if that works, then I'm fresh out of ideas. Am I looking in the right place? Is this fault common? Easy fix/diagnose? Any help appreciated!! cheers, -s Quote Link to comment Share on other sites More sharing options...
P15UL T Posted May 12, 2008 Share Posted May 12, 2008 never heard this one before, what you are going to do sounds about right, where do the bleeps come from ?? is it connected to the cars audio equipment or a seperate device that could be faulty ? Paul Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted May 12, 2008 Share Posted May 12, 2008 never heard this one before, what you are going to do sounds about right, where do the bleeps come from ?? is it connected to the cars audio equipment or a seperate device that could be faulty ? Paul in the boot by the spare wheel, theres a small siren thingy Quote Link to comment Share on other sites More sharing options...
mcai8sh4 Posted May 12, 2008 Author Share Posted May 12, 2008 never heard this one before, what you are going to do sounds about right, where do the bleeps come from ?? is it connected to the cars audio equipment or a seperate device that could be faulty ? Paul in the boot by the spare wheel, theres a small siren thingy Thats the one! I assume the beeps come from the siren (alarm?), if it's not a common problem then looks like I shall be a pioneer. Everything looks good, so water shorting somthing is out of the question. I'm thinking it's just circuit died... or a loose wire. I'm hoping for the latter. Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted May 12, 2008 Share Posted May 12, 2008 never heard this one before, what you are going to do sounds about right, where do the bleeps come from ?? is it connected to the cars audio equipment or a seperate device that could be faulty ? Paul in the boot by the spare wheel, theres a small siren thingy Thats the one! I assume the beeps come from the siren (alarm?), if it's not a common problem then looks like I shall be a pioneer. Everything looks good, so water shorting somthing is out of the question. I'm thinking it's just circuit died... or a loose wire. I'm hoping for the latter. thats right it uses the alarm siren, does the alarm work ? is your reversing light working ? iirc they take the wires from the reverse light to act as a switch for the buzzer and sensors Quote Link to comment Share on other sites More sharing options...
mcai8sh4 Posted May 12, 2008 Author Share Posted May 12, 2008 tbh, I haven't tested the alarm since the problem started - I assume there's a 'test alarm' thread, i'll look it up and have a go! Reverse light is working, I imagined it used the same switch to activate it. I could always bridge the circuit to make sure - thinking about it I could also bridge the output for the sensors to check the siren. I'll have a play around tomorrow night. I'll let you know how I get on. Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted May 12, 2008 Share Posted May 12, 2008 tbh, I haven't tested the alarm since the problem started - I assume there's a 'test alarm' thread, i'll look it up and have a go! Reverse light is working, I imagined it used the same switch to activate it. I could always bridge the circuit to make sure - thinking about it I could also bridge the output for the sensors to check the siren. I'll have a play around tomorrow night. I'll let you know how I get on. leave the window open, arm the alarm, wait for it to settle a while then stick your hand across a motion detector - that will set it off Quote Link to comment Share on other sites More sharing options...
sl114 Posted May 13, 2008 Share Posted May 13, 2008 Maybe there is nothing behind you Sounds like a loose wire to be honest! Has the car got (extended) warrenty still? Quote Link to comment Share on other sites More sharing options...
mcai8sh4 Posted May 13, 2008 Author Share Posted May 13, 2008 Ok... I had a play after work, here's my findings. Tested the alarm,works ok. Checked the input voltage to the 'control box'. (call it what you want), input voltage = 11.6V - seems good. The buzzer/beeper ISN'T the alarm siren (behind the spare wheel), it's actually hidden under the plastic boot cover near the catch. Feel underneath and you'll find a small cylinder approx 1.25" dia 1.25" long. I tested that with a PP9 batt and some wire, works fine. So, power in ok. output beeper thing ok! Next step, ingnition on, select reverse, measure the output beeper voltage - ~1.4V constantly if sensors are clear or not. My conclusion... little black box of tricks is kaput!! I've took the circuit out and checked for burnt out componants but there's nothing obvious. I've also checked, the unit is only powered when the ignition is ON and reverse gear is selected. Looks like it may be a trip to the dealer or somthing to try a new unit - hopefully not too expensive. If anyone has any other suggestions, please let me know. Or if you want to know more about the unit/wiring etc, give me a shout, I'll help all I can. -s Quote Link to comment Share on other sites More sharing options...
Mathys Posted May 13, 2008 Share Posted May 13, 2008 Mine is beeping way too much after my respray of the whole car. So I guess the sensibility has to be re-adjusted in my case. Quote Link to comment Share on other sites More sharing options...
mcai8sh4 Posted May 13, 2008 Author Share Posted May 13, 2008 after having a quick look at the circuit earlier, I wouldn't say there is an easy fix to adjust the sensitivity electronically. There doesn't seem to be any variable resistors etc. I must admit I haven't gone as far as to figure out exactly how the sensors return the feedback to the control unit (poss be able to add to the input to reduce sensitivity but doubtful) or how the circuit works - looks complicated. If I do find anything I'll let you know. The only other thing I could suggest, mine was too loud (when the thing worked!!) so maybe muffle the beeper slightly (a sock would do it, just make sure it's clean - a car like that should smell nice too ). Quote Link to comment Share on other sites More sharing options...
Sammy Posted October 8, 2020 Share Posted October 8, 2020 Mmmm, I was looking for an answer to a possible issue that I could barley hear my rear sensor. All comments read above now leads me to the spare wheel area and have a look for a dirty sock muffling the small siren thingy?? will have a look and perhaps change the dirty sock to a thinner one :-) Quote Link to comment Share on other sites More sharing options...
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