I keep getting the '3 amigos' (ABS, TC and HDC) lights up on the dash - the fault code that's logged is 'shuttle valve switch electrical failure - intermittant, 254 times'. An engine off/on reset always clears the lights, and Nanocom clears the fault codes.
I found a LR Technical Information bulletin on this subject on the web - apparantly loads of dealers were swapping out ABS modulators to cure the 3 amigos fault, only for LR to find nothing wrong with the supposedly-faulty modulators. The Tech bulletin explains how to test various parts of the wiring loom, and to check a couple of earth studs for corrosion/bad connections.
The part of the test that I've got a problem with goes like this:
Disconnect and inspect the 13-pin connector at the ABS modulator for moisture ingress and corrosion - no muck, and it's not wet/damp
Connect an ohmmeter between pin 9 of the ABS modulator connector (C0501-9 yellow/green wire) and ground, then monitor and record the change in resistance shown as an assistant very slowly depresses the brake pedal. Results should be as follows:
No pedal travel - resistance measured should be between 2555ohms and 4088ohms
Partial travel - 1533 ohms and 2554ohms
Full travel - 511ohms and 1532ohms
When I try this (with a fully calibrated DVM), I get 4960ohms with no travel........and however slowly we press the brake pedal the reading goes straight to 3490ohms :?
The Tech bulletin says that if you get a reading outside the min and max values, then the ABS modulator is knacked, and needs replacing - but the damn thing is not being checked, as the DVM is measuring resistance between the car-side wiring loom, the SLABS ECU and the brake pedal.........
I'm either doing something wrong, or the Tech bulletin is crap - can anyone shed any light ?
