Cruising along the highway at about 70, when the amber and red warning lights came on the display, Engine Failsafe Mode and Restricted Performance popped up on me. Since my speed was reducing and I was in traffic I tried popping it in neutral and shutting the motor off for a few seconds and restarting, hoping it'd reset itself. No dice, so I got off at the next exit and into a parking lot. Shut it down, hooked up my scanner and checked for codes. Nothing stored, but a pending code of P0740, which my code reader says is a "Torque Converter Clutch Circuit/Open". Decided to return home to swap for my backup car to get to work and darn if the car didn't fire right up and run flawlessly on the 20 minute ride home.

Little background that may or may not be relevant, when I first bought this car in summer of 22, I had a bad dual linear switch issue and was stuck in the garage for a few weeks while I diagnosed this and tried repairs without replacing it. During this time while checking for codes, I started getting a "Gearbox Overheat" message on the display...on a stone code car that wasn't even running. On advice from this forum I pulled the TCM connector from the trans, found it had a tiny bit of residue on it, cleaned it and sprayed the female port on the trans with electronic cleaner, dried and reconnected and there have been no trans messages since then. Since those connectors on the trans are a known issue I'll be inspecting it and probably just order a replacement, they're cheap and easy to install. Trans fluid ought to get done so I figured I'll order the 722.6 maintenance kit from EEuroparts, do a fluid and filter change and the kit includes a new connector anyway and seems pretty complete apart from a couple gallons of fluid. Link below, if anyone has a better recommendation I'm happy to hear it. Specific fluid recommendations?

https://eeuroparts.com/product/oem/3086551KIT

I've seen a couple threads on here that said the TCM connector replacement and another that needed the torque converter rebuilt, so solutions are all over the place. I'm leaning towards a more likely electrical connection issue than a mechanical one as I would think I'd be experiencing drivability issues with a failing converter, but I've had none at all...also wishful thinking on my part.

So, thoughts? Advice? Much appreciated.

 

I think you’re on the correct path since the conductor plates are known to go bad.

Not that I’m experiencing any kind of problems with my transmission but, I’ve had a complete kit including blue top solenoids waiting since November 2021 to go into mine. 😳🤦🏼‍♂️

 

Trans maint kit ordered, I'll probably pull the trans plug tonight for inspection and cleaning.

What's the current recommended spec of ATF for the XJR trans? Is it MB 236.14 as I read in an older thread or has that been replaced by a newer standard? Couple gallons for a normal drain, screen change and refill? Wal-Mart has Valvoline full synth ATF for $7/qt and it lists MB NAG-1, 236.14 and 236.17 compliance.

Thanks!

 

I use this in both of the XJR’s and I haven’t had any issues with many thousands of miles.

 

Cool, thanks! Bonus points, I think I can use this in my power steering flush and pump change!