K Light

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K Light

Post by BOB6844 »

I have a warning light on my GTi dashboard, which shows a graphic of an engine with a "K" overwritten. This is presumably the "K Light" I have found a few references to.

Not having the original owners handbook, I am not certain as to what the problem will be. What is the function of the "K Light"? There has been much handling of the ECU and its various connections due to my recent ABS fault, which has been replaced immediately with a different one! Possibly related events.

Any suggestions as to a fault detection process?

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Re: K Light

Post by Way2go »

The K light has nothing to do with the ABS or the associated control unit located beneath the passenger seat.

The main ECU which is associated with this light is located beneath the drivers seat. If sensor info is faulty or poor running is evident then the K light will illuminate and the ECU will enter "limp-home mode". There are several sensor feeds to the ecu and a MAP (pressure) feed too if you have the Bosch Motronic 3.1 injection system like myself.

Be warned, if you have been disconnecting the battery you may get erroneous indications of the K light for a couple of starts before the system settles down again.
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Re: K Light

Post by Kitch »

Way2go wrote: The main ECU which is associated with this light is located beneath the drivers seat. If sensor info is faulty or poor running is evident then the K light will illuminate and the ECU will enter "limp-home mode".
It enters limp-home mode whenever the light comes on? :shock: Jesus, I'm glad mine doesn't have the K-light :lol:
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Re: K Light

Post by RobC »

It doesn't always enter limp mode! Depends on the fault.

Mine's always lighting up temporarily when sat in traffic - last time I had the fault codes read it was due to the knock sensor, presumably being triggered because of a 16v's notoriously lumpy idle. It soon goes out after a while, or as soon as the revs rise and the engine smooths out.

However if your K light is on permanently then I'd advise getting the fault codes read. Somewhere online there's a little circuit diagram of how to build your own simple reader.
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Re: K Light

Post by Jaba »

First thing I would check, with ignition off is all the ECU engine connectors by replugging them all including the ECU itself and its circular connector in the engine bay (I assume its Motronic 3.1 on your 1990 GTi). Make sure also that they look as though they are on the correct sensor, particularly the coolant temperature sensor as this will give a permanent K light.

You can read out the error codes if you know how, as far as I remember you connect the diagnostic plug to a switch or jumper wire and earth it for a couple of seconds then read out the flash sequence of the K light.
Gabor's site tells you how here : http://citroen.tramontana.co.hu/fuel-ex ... components

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Re: K Light

Post by Tim Leech »

I had mine come on the TZI when it stalled but soon went out again after a short drive.
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