Parking Sensors Not Operational

[Mikc]

Having looked through this forum, it is obvious the fault I have is not uncommon!!

Sensors have been playing up for some time now, normally when wet weather, but would start working again when wwather dried out, (even from this it sounds like moisture getting into either the sensor or connectors). Unfortunately they have now been inoperable for several months and I guess it is time to get it sorted.

Usual fault indications - constant beep from rear speaker and flashing light on dash switch, regardless whether selected by reverse or switch.

Have so far removed each of the rear sensor wiring connectors in turn with no change of symptom; have also isolated all the rear sensors by splitting the connector within the spare wheel bay. Again no change to symptom, and all connections look clean, all wiring looks OK. Control unit looks bone dry - although rear washer doesn't work, have never found any water under the passenger seat (or anywhere else!).

After investigating on this forum, have listened to each sensor in turn, and all click. So now my questions!

 

I am guessing this only confirms that the 'send' path is correct, and there could still be a fault with the receive / return (wiring) to the control unit. Which colour wire is the return? (Can't remember what colours I saw, but guess there's a black there for common)

Can I isolate front sensors as a bank without removing central trim line of bumper? Can this be done via one of the plugs on the control box, or does the control box 'sense' an open circuit and deem this a fault?

 

Will probably tackle the front section over weekend if it ever stops raining!!

[Mirez]

Ok, The constant tone and flashing LED indicate a fault with the system and a fault will be generated if one or more sensors are defective but this INCLUDES being disconnected (O/C)- therefore disconnecting them either individually or as a bank would only put the system into error state anyway and thus won't prove anything.

 

There are three wires to each sensor, a common ground, common supply and individual signal cable - if you've checked the first 3 to 5cm of wiring from each sensors connector then its unlikely to be a wiring fault - its FAR more likely to be a defective sensor, the "tick test" is a crude and very basic test to see if there is power and ground to each one but thats it - internal sensor faults are just as common, find someone local with diagnostic kit and get the error code read - it'll tell you instantly which one(s) are defective.

[Mikc]

Mirez

 

Many thanks - I had a feeling this might be the case.

Have now checked as much wiring as possible, including removing the trim strip off the front bumber and accessing the front sensor wiring. I see why there are gripes about the wire length there!! I have also reseated the connectors on the control module, just to be sure.

If there is anyone willing to offer a look with a diagnostic kit, would be much appreciated - Fareham / Portsmouth / Southampton area.

In the meantime, I will try and access the dash switch.

Mick