Rear left ABS open circuit

[Karl68s]

I've replaced both sensors on the rear.
Cleaned the plates on all, fitted the washer mod.

Cleared all the faults and reset the BSI but yet the fault still remains.
What's next ?
Do I start pulling out cabling all over the car to find a possible break in the cable somewhere between the plug and the ABS unit or does anyone have another idea.

[CAB]

new faulty sensor?

didn't know of a washer mod on the 407's, defo 307's.

[Karl68s]

Tried it on the 407 to see if it fixed it.
Not a faulty sensor as if I swap the rear plugs it's still rear left that shows the fault.

[battlestar]

Check the cable that goes from under the rear seat to the ecu. What you can do is unhook the abs sensor under the seat, unhook the other side of cable at ecu, its the large 25pin black connector, only one on esp ecu. Its right under the car battery.

Once you have everthing disconnected, check the continuity using multimeter on the cables leading from esp ecu to the interconnection under the rear seat. In the large connector, pins 21 and 22 lead to the rear left abs sensor and pins 9 and 10 to the rear right abs sensor.

After checking everything, if that part of the cables is ok, connect the abs sensor under the rear seat, then check the resistance on the ecu side of the cable, you should get 5 mega ohms, and if you get 3 mega ohms, that means that the polarity is switched, which means you will either have to take apart the connector under the rear seat and switch the wire sides or cut the cable and solder the wires crossed.

take care when measuring resistance, because if you switch the probes, naturally you will get the measurement as if the polarity was switched itself.