Was your ECM working well before the transmission swap?

Without having read all DTC-s, your mechanic and/or electrician may be doing unnecessary guesswork. As suggested by "Addicted2boost", get the codes from the ECM and TCM and post them on this forum.

 

Alright, I've got them. There's only three codes apparently. They are as follows: P1121, P1632, C1156. Thanks.

 

If I was at work, I’d have access to all those codes. I know they exist on here somewhere. I know the P1121 is a TPS or a PPS code. Not to undermine the P1121, The one that will make the car most unhappy is the C1156. If I’m not mistaken that code is for the right rear wheel speed sensor. The right rear wheel speed sensor is what sends your main vehicle speed to the speedometer. If the IP doesn’t receive this signal, that will be the one to send your vehicle into fail safe mode. I’d ask them to visually inspect the rear wheel speed sensors and if those look ok, swap the right and left rear sensors side to side. Assuming that RT RR sensor is open, it will still have an ABS fault light on but, it should act a little more normal *after* they clear the codes and drive it again. The speedometer should work again and drive better.

 

Will do. I scrolled around the forums here for these codes and I read that P1121 is a throttle body/sensor code. Could it just be the throttle?

 

From Jaguar DTC Summaries AJ27 Engine Management – 2000 MY (PPS - Pedal Position Sensor):


From Jaguar DTC Summaries 5 HP 24 Transmission Control System – 2000 MY ON:


I do not have the Jaguar document for "C codes". Based on generic listing of codes, C1156 appears to mean "Speed Wheel Sensor LF (Left Front) Circuit Open"

Since you have P1121 (failure at PPS) and P1632 (loss of throttle data), I would first look into the PPS (potentiometer on the Throttle Body) and into its connector.

 

Thanks for that correction M. I must’ve gotten my numbers (from memory) mixed up.

Edit: I just went to jagrepair.com and got all the codes. I forgot about that site. It’s true about the “if you don’t use it, you lose it”.

 

Guides for you.

 

Sorry, not sure what a potentiometer is. According to the DTC code explained at jagrepair.com, 1632 means ECM Failure. So maybe that electrician wasn't too far off? Or is that code caused because of throttle issues too?

 

You have P1121 (failure of PPS) and P1632 (loss of throttle data). Loss of throttle data (to the ECM and/or TCM) suggests that it is caused by the problem at the Throttle Body (at the PPS). It could either be failure of the PPS (not uncommon) but it could be as simple as a bad contact at the connector to the PPS so I would inspect/clean the connector pins first. The Throttle Body:

 

Man I hope you're right. An entire ECM replacement would be a pain in the ***. So, a simple unplug and clean the PPS? Can I clean it with anything or should I use specific cleaners? Thank you kindly for your responses so far by the way.

 

I suppose they removed the TB to get the top transmission bolts out but, they could’ve used a long extension from underneath to do it as well. Seems plausible that they disturbed the TB enough to make it unhappy. 🤷‍♂️🤷‍♂️

 

Yeah that would make sense. Will check in with them tomorrow afternoon to see whats up and update them on what to do next. Thanks.

 

I don't think the PPS can be cleaned/serviced as it is a sealed unit. It is not available as a separate part (not even its knock-offs) so, if you need to replace it, you will have to look for a used one (or a complete used TB if no one is selling the PPS separately).

In addition to checking the connector to the PPS, you may also need to check the continuity of the wires that connect the PPS to the ECM. See the attached pdf document which contains relevant pages from the Jaguar Electrical Guide. On the first four pages, you will find info on what the normal voltages should be on the PPS. The last page is the wiring diagram showing how the PPS connects to the ECM.

 

Another document having info on the TB and PPS.

 

Thanks for the info! I should probably mention that these codes and issues were not here until the transmission was replaced, meaning the TB was probably meddled with during replacement. So perhaps there's still a chance of there being no damage, just some misconnection or such.

 

It’s also possible that the wires within the connector needs to be pushed in a bit more with a very small flathead screwdriver so there’s a more positive connection. From the backside of the connector, you gently but firmly push in the round seal which forces the female pin to connect better with the male pin of the TPS/PPS.

 

Yeah so he said everything looks good on the PPS, no corrosion and good contact. I told him I'd get a new PPS and he said it's better to get the whole throttle body just in case. Should I? Considering the codes are PPS specific? It's also weird to me how the issue wasn't there before the transmission swap.

 

I know it’s frustrating about the whole situation. Let’s just move past this and just ask for your old TB back before you leave the place with your car.

Definitely get an entire TB over the single PPS.

 

Frustrating and disheartening . So replace the TB and bring the old one with?

 

How does this one look? Ebay
It has 75k miles

Or, this one? It's a refurbishing service.

Ebay