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Well I moved Mama's car out of the garage and after being on the charger again all night I disconnected the battery from the charger moved all the tools and parts from the top of the car to a bench I set up. Got in the car and after about 7 or 8 tries it started. To my surprise it no longer is showing "GEAR BOX FAULT" in the dash message window. It still shows "RESTRICTED PERFORMANCE" however. This has given me new hope that at some point I may actually be able to drive the car to dinner once in a while.
I've taken some more photos of the engine compartment. I removed the black round cap referenced in my above post and it does in fact appear to be another ground cable.
I'll take this apart and clean the eyelets and bolt and nut.
It appears to come out of the ECM/TCM compartment and disappears under the throttle body air intake. I'll take that off and see if I can trace it and clean off whatever contacts are there.
I looked around in the left side compartment, the one with the brake booster, but I'm not sure I'm see any ground cable, strap or connections. If anyone sees something I'm missing please let me know.
Any ideas on the "RESTRICTED PERFORMANCE" message. Would doing a hard reset (removing positive and negative cables and touching them together for 30 seconds as I recall) do anything to clear that or do any harm other than the reset? I drove the car around the block and it was shifting gears normally. Prior to this it was struggling.
I've replaced that thin foam insulation around the cover for the ECM/TCM compartment. I'm not sure that will help with any future water ingress but I figured it couldn't hurt. I am still at a loss as to where the water came into the box. Since I'm no longer getting the "GEARBOX FAULT" I'm thinking I've cleaned the pins and connectors on those components sufficiently.
I'll wait to hear back from anyone before I take any more steps. Even though I'm no longer getting the GEARBOX FAULT I think I'm still going to either clean, or replace the ground strap under the car going from the frame to the gear box. I just have to wait for it to get here Sunday.
Thanks again for all the help and my apologies for my rants.
My mistake on the cable going from the ECM/TCM compartment. Turns out it goes out of the compartment and towards the firewall. I couldn't see any further down the side so I'm not sure. Could it be going to where the frame to trans strap is?
It's the cable with the yellow tape on it. Here it goes down the side of the engine compartment towards the frame.
When reattaching the throttle body air line I noticed that the gizmo that comes out of the filter box and through the fender well (see below) was not connected to the box. I'm not sure how it got disconnected but there is nothing holding it to the box but the pressure fitting. Could this have been causing the "RESTRICTED PERFORMANCE" message?
I went out and did a hard reset to see if I could clear the "RESTRICTED PERFORMANCE" message. Disconnected the battery cables, held them together for 30 seconds and reconnected them. Got in and started the car, no 'RESTRICTED PERFORMANCE" message, but the Check Engine light was on. Drove it around the block and back into the garage. I connected the OBD2 and got the following codes:
ECM -
P1643 CAN link engine control unit/transmission control unit circuit/ network malfunction
P1748 Pressure regulator 5 malfunction
P1797 CAN transmission control unit to engine control unit malfunction
I've taken some more photos of the engine compartment. I removed the black round cap referenced in my above post and it does in fact appear to be another ground cable.
That is the battery power connection to the fuse box. It's good to clean it, but the battery should be disconnected.
ECM -
P1643 CAN link engine control unit/transmission control unit circuit/ network malfunction
P1748 Pressure regulator 5 malfunction
P1797 CAN transmission control unit to engine control unit malfunction
Most of the codes indicate communication problems with the transmission. As I suggested earlier, in addition to finding and cleaning the ECM/TCM grounds, the next thing I would check and clean is the electrical connector at the rear of the transmission. If that does not improve things, it will be time to move on to the pinpoint tests for these codes in the Workshop Manual, Or, if you'd rather spend a little money first, find a good salvaged TCM with the same part number and VCATS version as yours and see if it behaves better than your current TCM.
Most of the codes indicate communication problems with the transmission. As I suggested earlier, in addition to finding and cleaning the ECM/TCM grounds, the next thing I would check and clean is the electrical connector at the rear of the transmission. If that does not improve things, it will be time to move on to the pinpoint tests for these codes in the Workshop Manual, Or, if you'd rather spend a little money first, find a good salvaged TCM with the same part number and VCATS version as yours and see if it behaves better than your current TCM.
I am still confused as to where the ECM/TCM grounds are located. If there is anyone out there who can point these out I would gladly clean them.
When I took the car to the local Jaguar shop I brought with me a newly purchased TCM which matched the VCATS numbers and it was installed at that time. The shop called me to pick the car up because, while they could not get the CAT monitor to reset (which is why I brought it in to them in the first place, they needed the car moved because they had other cars coming in. After driving the car home the CAT monitor reset and I was able to get it smogged.
How does one do "pinpoint tests" for this "GEARBOX FAULT" message? Why would it go away only to come back again?
The new trans/frame strap should be here tomorrow so I'll replace that once I get it.
I did another search for the ECM/TCM ground locations and found a thread with a photo of the compartment with the brake booster on the port side. So I went out to pull the car back into the garage and now there's no "GEARBOX FAULT" message. GRRRRRRRRRRRRRR!!!!
Anyway I took some pictures of that compartment and what appear to be ground connections. I don't know if either of them are from the ECM or the TCM but here's what I have:
If those are the ground connections that need to be cleaned I'm not sure how I would get down in there to do that. There does not appear to be enough play in those wire looms to allow me to pull them up to clean the eyelets or the studs.
I am hesitant to remove and clean them because it would mean disconnecting the battery again and it seems that every time I do that something bad happens. I am thinking about waiting until I get the frame/trans ground straps and do it all at once.
Well I've taken it for a bit of a ride. Ran the trans through all the gears, kicked it down into a lower gear to speed up and came home and still have no error messages about the gear box or restricted performance, or any thing else for that matter. I'm not sure it's from me cursing at it, threatening to plant it full of roses, or just slamming the door enough times but it seems to be functioning ok for now. We shall see what happens tomorrow.
Well just got the 2 ground straps delivered. Unfortunately they aren't going to get installed today, birthday party for one of the grand kids. If I spent half as much time working on the car or the garage as I do with grandkids I'd have the finest car parked in the cleanest garage in the land, LOL. Oh well. The straps are 4 gauge so they should work well. Just have to clean off an area on the frame and find a bolt on the trans that I can get to and clean that are too. I'll pull those 2 ground contacts off the port side compartment and clean them and reinstall, since I'll have the battery disconnected anyway. I think I'll make an offering to the electrical gods that everything goes back the way it came off and that there are no error messages on the dash when it's all done.
Regarding adding a second engine ground strap, I usually use the existing mounting point on the body (clean it as you mentioned) and just stack the new cable's ring terminal over the original one.
At the engine block/transmission end, mount your cable on an accessible bolt on the engine block side, since the engine ground strap is the critical ground path for the spark plug electrical circuit. Mounting the cable on the transmission side could introduce unwanted resistance due to the imperfect electrical connection between the engine block and transmission bellhousing.
Thanks Don. I’ll look around for another place on the block for the strap. From what I recall when I was under the car replacing the O2 sensors the bolt that holds the factory strap to the transmission is very difficult to get to and I think it’s blocked from coming all the way out by the catalytic converter. But I’ll check once I get under it.
I got in the car today to head over to the surgeon's office for my follow up from the gallbladder surgery and I noticed something. My steering wheel now goes all the way up and all the way back when I shut the car off. It used to either go all the way up or all the way back but never both. I'm not very leery about disconnecting the battery again to put the new ground straps on the engine/transmission/frame and cleaning off those last 2 ground connections in the left side compartment. Am I correct in thinking that messing around with those connections without disconnecting the battery is a no no? If that's the case I think I'll just leave things as they are until another electrical gremlin pops it's head up.
