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Limp mode and poor running

Posted: Sat Feb 01, 2025 12:58 pm
by Mini
I have an XK8 1999 with the following IDS codes

Engine control - P0336, P1646
Instrument pack U1260, U1261
Transmission control P1798
Climate control - request cannot be processed due to a bad specification or missing parameters
Restraint control module - communication with module has been lost.

I am guessing the P0336 and the P1798 are the key ones to go at initially ?

Any thoughts ?

Thanks

Re: Limp mode and poor running

Posted: Sat Feb 01, 2025 7:13 pm
by ptjs1
Mini,

First of all, have you tried ensuring that your battery is absolutely fully charged, then clear the codes, then drive the car and see what returns?

It may well be that you have component problems, but I would always start with that approach first.

As you probably know, P0336 & P1646 (assuming they are not spurious) relate to the crank sensor and one of the lambda sensors.

Good luck

Paul

Re: Limp mode and poor running

Posted: Sat Feb 01, 2025 7:17 pm
by Mini
Battery is new and fully charged.

Re: Limp mode and poor running

Posted: Sat Feb 01, 2025 11:36 pm
by Astromorg
I'd go with that advice to get to a good starting point for what's to come.

Somewhere along the line it looks like your you're going to find an underlying problem with the CAN bus system and maybe the SCM one too as indicated by the P1798. That could be fun!

For the AC problems. start here if possible

http://www.jagrepair.com/images/ACCompr ... 0Codes.pdf

You seem to have quite busy programme with this and the '96 one!