P1601 fault XJR
P1601 fault XJR
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Discussion

varsas

Original Poster:

4,075 posts

231 months

Tuesday 20th October 2009
quotequote all
Hi all.

Twice I've had a 'gearbox fault' come up after driving slowly down hill. It's very intermittent, it hasn't happened in the last 500miles. The error code is P1601 ECM/TCM Serial Communication Error. Is that...bad...?

The car is a '98 XJR (so I think it has the Mercedes gearbox) I've heard the TCM can be an issue in these cars. Both times I've switched off/on and it's been fine afterwards.

Also I want to haver the gearbox oil changed. Any suggestions/tips? Where should I get the oil from, for example. I know a local Merc/Jag specialist I was going to take it to them to have it done, they should know how to do it!

NormanD

3,208 posts

257 months

Tuesday 20th October 2009
quotequote all
I take mine to a local Jag specialist near J4a of the M3, I don't know if that is handy for you in the SE

He can sort the error code for you as well

varsas

Original Poster:

4,075 posts

231 months

Tuesday 20th October 2009
quotequote all
Cheers, there are a couple near me who I know. Maybe I should have spoken to them before asking teh interwebs...

Tame Technician

2,467 posts

233 months

Tuesday 20th October 2009
quotequote all
Means the TCM and ECM aren't talking to one another.

Open up the cool box and see if the ECU's are underwater or any obvious wiring fault.

varsas

Original Poster:

4,075 posts

231 months

Tuesday 20th October 2009
quotequote all
Tame Technician said:
Means the TCM and ECM aren't talking to one another.

Open up the cool box and see if the ECU's are underwater or any obvious wiring fault.
The cool box? I'm not sure where/what that is, I presume it's where the ECU lives. Water would kind of make sense, it did happen after going down hill.

Tame Technician

2,467 posts

233 months

Tuesday 20th October 2009
quotequote all
Bigish black plastic box contains both engine and Gearbox ECU's. + a cooling fan hence coolbox.

Under the bonnet, near side of the car at the back.

http://www.eap-direct.com/11421556_8X.jpg

Look at that pic, OK its not an "R" & its a left hooker so its the sides are reversed but its all i could find.

See where the brake fluid cap is on this left hooker. Thats where the ECU's are on yours. removed the plastic trim, one screw IIRC, and then you can see the box, think theres a small fuse box in there too, just ignore that, your looking at the bigger box.

Has tamper proof screw which are a pain, but a large flat bladed screw driver and alot of downwards force and they will come undone.


Edited by Tame Technician on Tuesday 20th October 22:08

varsas

Original Poster:

4,075 posts

231 months

Wednesday 21st October 2009
quotequote all
Cheers, will do!