Rover 200 & 400 Owners Club

Hi,

Very frequently the Check Engine light comes on in my car. It usually comes on within two to five minutes of driving, and resets by turning the ignition off and restarting the engine, and then two to five minutes later it comes on again. It comes on whether the car is being driven lightly or accelerating briskly, and in any gear. The only noticeable change when the light comes on is that the autobox lock up drops out if locked up, or the autobox does not lock up when it normally would lock up. Around town it is not really an issue but on the motorway at 100kmh/60mph the engine revs 300rpm higher which increases noise and fuel consumption.

So my question is what inputs/faults would create a Check Engine light that also stops the autobox lockup working? Other than that the car drives no differently.

A further question - there are many useful documents in the Members Area but I cannot find any reference as to the logic of what input causes the output to not lock the autobox? Does anybody know what the decision tree matrix to trigger the Check Engine light?

Thanks in advance!

Tony

A quick easy warning light fault is H.T leads not being fully home in the dizzy cap. Unlikely to be the cause of the gear box issue though.

Thanks TB - will check the HT leads are tight!

So my question is what inputs/faults would create a Check Engine light that also stops the autobox lockup working?

A look at the wiring diagram might help with this...

Yes - already studied the wiring diagram - the auto lockup is directly controlled by the ECU - so the mystery is what logic is built into the ECU that drops out the auto lockup?

I have hopefully got this issue fixed - it appears the lambda oxygen sensor was faulty - now replaced and so far so good with the autobox torque converter locking up again. But why would a faultly lambda sensor stop the auto lockup?? Wish I could find documentation as to all the algorithms in the ECU!