75ZT Community

I seem to attract questions about parking sensors in the other clubhouse so here is my simple tip, this may or may not solve your problem
Symptoms: Long tone when reverse selected & sensors inop.

Possible cure: What I found with my car & subsequently people have found after taking my advice is corroded joints in the wiring.
If you stick your head under the bumper there should be a grey multi plug check this by unplugging & visually inspecting the terminals for corrosion, failing that follow the wiring towards the bumper & after a couple of inches you should come across a section wrapped in black insulating tape, unwrap it & this should reveal 2 sets of wires wrapped in blue tape, unwrap these & you should find some crimped metal connectors joining each set of wires together, by now these have probably been wet & will have corroded usually to a powdery peppermint green lump, simply chop out the corrosion, bare the wires back & rejoin using heat shrink connectors & retape the harness.

Symptoms: No long tone & sensors inop.

Possible Cure: Check to see if the reverse lights are working, if not then this would tend to suggest the reverse light switch has failed in the gearbox, unplug it & short the 2 terminals in the plug & see if the lights/sensors are working if they are then replace the switch

Further to your post Col....


To solve this get one parking sensor you know to be working and try replacing each sensor with it until you have found the broken one.

Will have to try this fix - I intermittently get the long tone for no reason. Thanks for the post, looks like quite a common problem.

WOT LEWIS SAID
Well added mate go to the top of the class

DeuxGazoles wrote:WOT LEWIS SAID
Well added mate go to the top of the class

Cheers Mate

Cowley_MOA wrote:

DeuxGazoles wrote:WOT LEWIS SAID
Well added mate go to the top of the class

Cheers Mate

I checked my sensors by putting the car in reverse with the ignition on and the engine off and the putting my ear to each in turn to listen for the little clicks. I get the long tone oocasionally but all 4 are clicking away.

Will get the back bumper off and have a good luck at the wiring.

Sorry Lewis. Although one sensor can cause the thing to stop working, its not because they are wired in series.

Each sensor has three wire. These are power ground and signal.

The power and ground are paralell.

The signals are individually connected to the PDC ECU (Engine Control Unit).

The ECU can send a 'ping' on each sensor and listens to the echo on that same sensor, plus the other sensors.

So if one sensor goes faulty the whole system shuts down as it can't be trusted.

An easy way to check your sensors is this. Ignition on, select reverse.

Stick your ear close by each sensor in turn. You should hear a faint clicking from each sensor. If one isn't clicking, there's your problem. Could be the sensor itself, but more likely the wiring.

(I don't need to say ignition on but engine NOT running, do I?)

Thanks to Colin fixed my sensors a while back , he was spot on about corrosion unfotunately i took me a couple of months to take tape off and have a look as all looked well with loom but was not ! . Will try to attach a couple of pics :

Mcolskiey PSU ECU is getting power from gear box but nothing to the ECU from the FKI any suggestions

Sorry don't relly understand the question. I'm not sure what FKI refers to. I suspect autocorrect has 'got at' your post.

but nevertheless a great resurrection of an 11 year old topic