I've searched and I can't find the answer.

I have no cat and the heat light is on [JDM car].

Where is the sensor I have to ground? Some say it's under the drivers seat, other say in the transmission tunnel? Or in the Cat itself? My decat pipe has no sensor at all so where would the wires be?

If it's in the transmission tunnel what colours are the wires cause I have a mess of wires in there at the moment.

Also on PFC but this light was on with the stock ECU. Engine temps well within normal range.

Cheers lads.

 

The sensor is under the driver's seat - or more precisely, under the carpet/underfelt bolted to the floor pan. It's a plain alloy cylinder thing about 15mm high with "wings" for the fasteners.

Don't know the wire colours, it connects to the side harness with what should be a black 2 pin plug.....you might have to check function after bridging that connector, as I think the seat belt warning is the same type of plug!

 

Ideal thanks mate. Will get it up this weekend. It's annoying me looking at it all the time. Plus I need it for the PFC in case it throws codes. Not sure mine has any seatbelt warnings. It's a 93 JDM model.

 

I know all US cars had a heat sensor in the cabin bolted to the floor under the US passenger seat so it's above the main cat.

Japanese cars have a heat probe bolted to the cat itself. I've never personally seen this setup but I've seen pictures of it. Also most Japanese high flow cats have a provision for that sensor.

The system is pretty basic and primitive.

Also, the Japanese cars have the "overheat exhaust" light on the instrument cluster with the other warning lights. The US cars have a light on the trans tunnel near the ashtray. The US cars can't blink that light with the PowerFC since it's not connected to the ECU at all, I do have a writeup in the PFC forum somewhere on how to make the check engine light blink for the warning.

Dale

 

Yeah it's a fully JDM car in the UK just want to get this light off cause it's pissing me off now. Didn't bother me before but now the car is becoming more complete I want it gone. Will need to have a further in depth look around where the cat used to be.

 

I've swapped out a few harnesses over the years, from moderately early to version V1 cars, can't say I come across anything direct to the cat, but 91/92 era cars had lots of revisions - and there might have been something there coming off the emissions harness as that seemed the most revised of all, with probably 8 or 10 types early on!

I'm of some doubt there's even something resembling a CEL in the cluster, everything has to go through the diagnostic box, unfortunately there's quite a few changes there too, with 93 a bit basic compared to later cars.

I wouldn't bother pulling seats out, just lift the door scuff panel and carpet in that area to find the B19 connector. These are Oz mid 90s diagrams, but you might be in luck with Blue/Orange and Black

 

Nice one cheers for that!

 

Looked at a Japanese 94/95 harness today, colours there are blue/black and yellow! Anyhow, shouldn't have a huge issue identifying, the only other nearby plug is 3 pin.

 

Ideal. Thanks for the info.

 

This is the plug. All done cheers for the help lads.

 

Yeah, forgot to mention the plug was white the other day, it's the adjacent plug which is black.....although I can't see that there at all in that spaghetti, ha.

 

Yeah it's a mess under there, how I got the car but it all works so I'm not messing with it haha.