Continuing the discussion from Greetings!:
I would like to ask a question.
I have a 1994 XJS 4.0L convertible and the transmission is going into LIMP MODE after stopping then moving forward. Takes off in in 3rd gear. Any suggestions?
The only way I know to get the DTCs from the TCM is Jaguar PDU. It is a very old/antique diagnostic tool that is REALLY RARE to find one in working condition.
I used to use one everyday back in the 1990s when I worked at the dealer. WDS was introduced in 1998 and was SUPPOSED to eventually have the software for the OBDI cars but it never happened. We even got the OBDI link cables for the WDS but never the software.
My guess would be the ‘CRAPPY-BLUE HELLA RELAYS’ or the TPS. Those were the two worst offenders for the gearbox fault.
86-178A Inoperative Blue Relay.pdf (79.8 KB)
The TPS sends signals to BOTH the ECM and TCM. Check for smooth resistance on both circuits (ECM wires and TCM wires)
A moving coil meter is the best way to measure but might be hard to find one anymore?
Good information. Thank you…
For the V12 at least, you can get the transmission codes without a pdu.
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Did not know that (or don’t remember that far back?).
Thanks for the info!!
I know this is terribly late but I did not report the solution to Jag Lovers Forum.
The problem was being worked on in July 2020 on a 94 Jaguar XJS 4.2L. I replaced an oil soaked TPS, all suspect relays, the trans ECM. No help. Then I spoke with a tech who led me to the trans selector switch on the side of the trans. I removed it and was able to open it and it was full of oil and corrosion. I cleaned he unit and returned it to service and that was the problem. No more intermittent limp mode encounters.
Sorry about the delay in reporting this but now maybe it will help someone with the same problem………Stephen2
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