Auto Gear Box Problem

Could you supply the model of XJS you have e.g. 1996 XJS 4.0 Celebration or 1989 XJ-S V12 5.3 HE? This would help with confirming the transmission model you have.

Its a 1992, 4.0.. Pre-facelift

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Hi,
I *think* that your transmission will be a GM 4-speed unit. As such, it should support a fault code reader? Have you checked to see what fault codes have been logged?

Rich

Snoopy11 said:

Its a 1992, 4.0.. Pre-facelift

Click to expand...

Wow, that's a rare beast indeed, seeing as how the facelifts started in '91 and the 4.0 wasn't fitted to pre facelifts...

Assuming it's got the 4 speed ZF 4HP24 box, then any of the wonderful bits of electrickery could be a cause. The throttle position sensor can even come into play.

BigCatXJS said:

Hi,
I *think* that your transmission will be a GM 4-speed unit. As such, it should support a fault code reader? Have you checked to see what fault codes have been logged?

Rich

Click to expand...

Sorry for my ignorance, but how do I do this. I dont know what the gear ox is but the selector only shows 2,4,and D

almcl said:

Wow, that's a rare beast indeed, seeing as how the facelifts started in '91 and the 4.0 wasn't fitted to pre facelifts...

Assuming it's got the 4 speed ZF 4HP24 box, then any of the wonderful bits of electrickery could be a cause. The throttle position sensor can even come into play.

Click to expand...

I assume its a pre-face lift. It has chrome bumper with black plastic splitter underneath. (Cant get a photo to upload)

Mark Woodward Classic Events! - The Wolseley Forum= This may me a link to a photo of it.

Log book has engine size as 3980. I am assuming its the original as the car has been well maintained since new with the service book stamped by a Jaguar dealer for 15 years.

Hi,
I'm afraid that I only have some experience with my V12 XJ-S which is quite different (GM TH400 3 -speed transmission). I've not yet needed to diagnose a problem with my Daimler Six which has an electronic 4 speed box with the J-gate selector.

At the risk of post re-blogging, this thread might help (although it's not XJ-S);
XJ40 • View topic - 1990 Daimler Auto problems

Hopefully, someone else with more experience will be able to help.

First of all I think it must be a facelift if it has a four litre engine. Second you need to confirm this for once and for all. Does it look like the old 3.6 bodywork or does it look slightly more modern?

The problem is most likely to be with the gearbox ECU. I had the same problem with mine - no code but the auto gearbox icon on the dash lights up when the fault happens until you restart the engine. I had to replace my gearbox Ecu in the end. This was about 8 years ago though. They're a bit cheaper to buy now on the used parts market.

It looks like the older models. (It does not have the newer looking large bumpers)
Where do I find the gear box ecu on the car and is it possible to check it.

Stupid question, but is there such a thing as a Heynes manual for the XJS. I cant seem to find one anywhere.

There is a Haynes manual that covers Jaguar XJ12 & XJS, but only upto about 1986, you can find it on Amazon

Can anyone tell me where I can find the gearbox ecu.

I know where I can get a replacement to check this problem, but I want to take the existing one off to take to the supplier and make sure its the right one.

If you could post or pm me you VIN, then I can confirm the exact model you have. From there a visit to the JDHT parts website will confirm the part number you require.

Thanks, Rich

Snoopy11 said:

It looks like the older models. (It does not have the newer looking large bumpers)
Where do I find the gear box ecu on the car and is it possible to check it.

Stupid question, but is there such a thing as a Heynes manual for the XJS. I cant seem to find one anywhere.

Click to expand...

The bumper didn't change until 2 years into the facelift production. The door glass is a better indication. If it's frameless, it's a facelift. The rear glass is also different, no plastic.

There isn't a worthwhile Haynes manual for the post '91 cars but the genuine Jaguar manual complete with parts catalogue is available from Jaguar Classic parts on CD for about £25 and often comes by return of post: JDHT

Snoopy, sorry only just seen this. The auto gearbox ECU is postioned above the back wheel arch on the driver's side. You get to it by removing the trim panelling under the passenger's window.