Rear Parking Sensors Mk II ZT CDT

[paulonsite]

Hi all, thanks for looking.

My parking sensors on a '54 MG ZT CDT aren't working. They failed a while back, and just before it happened I got the dreaded 'continuous beeeeeeep' from the sounder. I've done lots, but still haven't solved the problem! I AM FLUMOXXED!

Since the fault, and after burying my head in similar threads on the forum, I have replaced:-

• The gearbox reversing switch
• BOTH bumper looms (i.e. module to plug, plug to sensors)
• The parking module
• All the sensors
• the brake light actuator (different problem)

The relevant fuse is okay as well.

Now, when reverse is engaged (from key position 1):-

The control module gets and kicks out 10.75 V on the power wire all the way to the sensors, on all connectors, both sides of the external grey connector. Each signal wire has continuity and a roughly matching resistance.
The sensors are happily clicking away when an ear is pressed to them


If I disconnect the FINAL wiring loom, i.e from grey connector to sensors, engaging reverse gives me a loooooong beep. The sounder thus still works and indeed the 'headlights on' noise still works as it should.

I'm stumped. Can anyone unpick this? I've thrown about £100 and ten hours at this and a full OEM kit on eBay is £50...

Any help appreciated

[Jamiewelch]

Originally Posted by paulonsite

Hi all, thanks for looking.

My parking sensors on a '54 MG ZT CDT aren't working. They failed a while back, and just before it happened I got the dreaded 'continuous beeeeeeep' from the sounder. I've done lots, but still haven't solved the problem! I AM FLUMOXXED!

Since the fault, and after burying my head in similar threads on the forum, I have replaced:-

• The gearbox reversing switch
• BOTH bumper looms (i.e. module to plug, plug to sensors)
• The parking module
• All the sensors
• the brake light actuator (different problem)

The relevant fuse is okay as well.

Now, when reverse is engaged (from key position 1):-

The control module gets and kicks out 10.75 V on the power wire all the way to the sensors, on all connectors, both sides of the external grey connector. Each signal wire has continuity and a roughly matching resistance.
The sensors are happily clicking away when an ear is pressed to them


If I disconnect the FINAL wiring loom, i.e from grey connector to sensors, engaging reverse gives me a loooooong beep. The sounder thus still works and indeed the 'headlights on' noise still works as it should.

I'm stumped. Can anyone unpick this? I've thrown about £100 and ten hours at this and a full OEM kit on eBay is £50...

Any help appreciated

When you replaced the parking sensor ECU did you replace it with one with the same model number? I know there are 2 different types. Also there is a difference between the wiring looms that are for the 2 different ecus and I don't think they are interchangeable.

Potentially a T4 could shed some light on it as it should be able to talk to the parking sensor ECU and read out any potential faults.

[paulonsite]

@Jamiewelch Yes, the module is the correct one and the looms match exactly - I took the old one apart to check and apart from the common returns being crimped on one closer to the plug than the other, there's no discernable difference. Besides, they all get the voltage they need...

Good shout there though

[jackatesme]

I had similar problem no beep at all.advised on here the easiest fix buy a set off ebay £18,not fitted yet,on holidays, set looks good with full instructions.

[paulonsite]

@jackatesme

Is it this one please? https://www.ebay.co.uk/itm/22mm-Car-...IAAOSwFmRbwWVl

Ta,

[jackatesme]

Originally Posted by paulonsite

@jackatesme

Is it this one please? https://www.ebay.co.uk/itm/22mm-Car-...IAAOSwFmRbwWVl

Ta,

Not those, E.Bay:330340144598. £16.99. Many colours to choose from.