Anyone know where my ECU is located for my 94 V12 XJS coupe? I read that it is on the floor in front of the passenger seat - not there. Ditto driver seat. Only seat control modules found. My engine will not go over 500-1,000 rpm. Cap, rotor, plugs and wires OK. Not a head gasket problem - checked compression, etc. Suspect ECU failure. Help.

 

It is in the passenger side kick panel III n the footwell so I assume in a LHD that will be the right. Have you checked for spark on both banks?

 

Under the kick panel on the left / driver side is one TRW Seat Position Memory module - large. On the right / pass side are two modules - one is for Seat Control and the other is??? It is NOT a Marelli unit, it is a German HELLA unit DCB5608. I removed it while the engine was chugging along at 500 rpm, rough. It made no difference. If that was the ECU would removal not totally killed the engine?

Anyhow, I do have ignition / combustion on both A & B banks. But lots of missing. Almost feels like the timing is totally retarded and getting no advance. Can a Marelli distributor have an ECU by another mfg?

Any more ideas very welcome. Thanx. Dex

 

I have a feeling, that like the 6 cylinder 3.6s at least, the ECU is under a wooden 'blank' across the toe board on the passenger side. If you pull the carpet you may find a wooden plate, and under it the ECU. Basically, it is in the "hole" that the pedals, were they there, would be inhabiting.

Greg

 

I just noticed yours is a 94 I am not familiar with US models but if it is a 6.0L then you don't have a marelli unit but a power train control located in the front of the passenger footwell.

Did this just happen or was it after replacing parts?