So the other day on my way home the light for the transmission fault appeared on my dash, the car hasn't gone into limp mode and I was able to drive the next 20mins or so home trouble free. (changes between gear shifts seemed rough compared to normal but not sure if just in my head because of seeing the light)

So besides getting someone to scan it to find what is the reason for the light, are there any common problems i can check myself first.

Already checked fluid level all ok

Thanks in advance for anyone that can help

 

Hi Michael,

First of all, it's a good idea to add the year, model, engine displacement and mileage of your car to your signature line, since details vary from model to model and year to year. I'm assuming you have an X300 made from '95-'97?

One thing you can check is the electrical connector for the Throttle Position Sensor (TPS), the signal of which both the Engine Control Module (ECM) and Transmission Control Module (TCM) use for managing gear shifts. Oil contamination of the TPS electrical connector has been the most common cause of LHM on our '93 - perhaps your contamination is just bad enough to trigger the warning light without an onset of full LHM. The inside of the TPS can also be contaminated by oil, but try cleaning the connector first.

It might also be worth cleaning the engine bay ground points. I seem to recall that the ECM and TCM both use the one on the left inner fender and the ECM uses the one on the firewall/bulkhead behind the cylinder head. You might check my memory against the electrical manual, but cleaning the grounds may be faster. (the electrical manual is available in the download section of this forum)

Cheers,

Don

 

Thannks the tips Don, I will have a look at some of those,

Completely forgot to mention make etc, normally I do, 1995 xjr

 

The throttle position sensor should be nice and clean as i recently had the throttle body out and cleaned it all right up, this was about a week or so ago, I think I will have to get someone to scan it if there arent any other common problems that anyone else would be aware of that can be fixed at home

 

Reading the code is the best option. But I wouldn't retreat quite so quickly from the TPS. Could be you got some cleaning fluid or something in there that has it just as boggled as would oil.

 

I think it should be safe to cancel out the TPS sensor, as when i cleaned it i gave it plenty of time to dry off, and this light didn't come on untill about 1 - 2 weeks after it was cleaned, I'm in the process of finding a mechanic that can read my car. but hopefully will turn out to be a simple sensor or something,

I'm also guessing that parts for the gear box shouldn't be that expensive as its a turbo 400, the same out of many GM cars

 

Hi Michael,

Not to beat a dead horse, but were you having the transmission issue prior to cleaning your TPS? If not, it is possible that in cleaning the TPS you opened up a passageway for new oil and gunk to re-contaminate it, so like aholbro1 I would suggest that you not be too quick to assume the TPS is not contributing to or causing the transmission light. The issue may be something altogether different, but if you had never had the transmission light prior to cleaning the TPS, I would tend to suspect the two could be related even though 1 or 2 weeks passed before the trans light illuminated.

Just sayin'.... :-)

Cheers,

Don