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MG ZR ZS ZT Technical - ZT Alarm Fault & K Bus

At 4 o'clock on the last 2 days the alarm on my 2003 160 Turbo has gone off for no reason. I have taken the car for a diagnostic check and have had various faults recorded on the K Bus

Instrument Pack
1. Short to ground on kbus

Light switch controller ECU
1.Brake light switch short to ground
2.Aux Switch Input line Missing

Board Monitor ECU
1.Kbus Comms failure to radio
2.LCD Internal Com Open Circuit
3.Kbus recieve error
4.Kbus send error

The garage have said they need to start at one point in the wiring and just work through, but agreeing to that seems like writing a blank cheque for a bill.

Does anyone have any ideas about what the fault is and where it is likely to be?

Thanks

William

William

The thing is that unless you had done a diagnostic check immediately before this started happening you don't know how many if any of the listed problems were there on the one hand or are connected with the alarm fault on the other. In the latter case there may well be a 'magic bullet' which solves everything but in the former case you could well have to work through all of them before finding the one that is causing the alarm problem. ECU fault codes are notoriously confusing and inaccurate in some cases, they are only as good as the software designers imagination in thinking of things that might go wrong. My daughter's Honda failure to start was diagnosed as an injector problem, but turned out to be the main relay, only discovered by me going through the circuit with a volt-meter. If paying someone else then yes it can be expensive, if for no other reason that most workshops have no idea even about basic electrics, let alone the sophisticated electronics on these cars. Most of the time all they can do is swap modules and components (at your cost!) until the problem goes away.

If you can't get a clue what is setting it off from the LED then try locking it with the key instead of the plipper, which does not enable the ultra-sonic system just the permiter switches and immobiliser, and see what happens.
Paul Hunt

This thread was discussed between 10/08/2009 and 12/08/2009

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