Today after 1.2k kilometers ride the check engine light came on again. It is the P1236 again. Logically the coolant had nothing to do with this. So need to start investing again about this problem. Running out of options that are not the fuel pump though. Maybe will try to change the fuses of the fuel pump.

 

The coolant level has nothing to do with the code you are getting. The code points you to the fuel pump. Now is the pump starting to go or possibly the something in the wiring or maybe a slightly loose connector? I don't know. I do know you have been dealing with this for 4 1/2 months and have been living on borrowed time. You know how things always seem to work: at the worst possible time it will decide to not start and you will be stuck somewhere. Might be time to take it to a dealer or some other professional shop you trust to fix it when you can do it on your terms and not have to have it towed in.

 

You are right, thinking that the coolant had anything to do was silly. Unfortunately i moved in Stuttgart Germany around 1 year ago and still didn't find a good specialist for jaguars. Have been in like 3 guys but every one of them quite frankly didn't know much about the car and somehow tried to avoid. Also at the only dealership in town they seem to like to fix more new Jaguars. Still need to find a trusted mechanic. Advices are welcome of course . Will send it back to the garage since you are right, my time is counted. This fuel pump will just decide to die in the worst place.
Apart everything yesterday car developed a grinding noise at around 50km/h from the rear side that looks like a wheel bearing to me. Still one more reason to take the cat to the doctor. Thanks a lot for the help. The most helpful source ever for Jaguars.

 

P1236 points to a faulty Fuel Pump Control Module (FPCM): "Fuel pump not activated when requested by the ECM". Possible cause: "ECM to fuel pump control module control and / or feedback circuits: open circuit, short circuit, high resistance. Fuel pump control module failure."

Your X-Type's symptoms align with this description: Misfires up hills and when you stomp on the accelerator pedal - conditions calling for more fuel on short notice.

The FPCM is under the left, rear seat cushion. This thread has pictures: https://www.jaguarforums.com/forum/x...-start-112305/

The FPCM powers the fuel pump with a square wave and pulse width that modulates, as instructed by the ECM, to provide more power to the fuel pump when accelerating and under load, and less power to the fuel pump when coasting and idling. Fortunately it's a relatively inexpensive part, and easy to access and replace.

Good luck!

 

Thanks for the response. Is this the part number right: C2S44963? Didn't know that the modulator module of the fuel pump was outside the fuel pump assembly. Thought everything was above the fuel tank. This one is easy to access and check. Will first check wiring maybe something went wrong.

 

Yes, the part number for the fuel pump control module is C2S44963 in Jaguar's database, and 1X4F-9D372 in Ford's. Google or search eBay for these part numbers, or "Fuel Pump Control Module" or "Fuel Pump Driver Module".

Be thankful the FPCM is easily accessed under the rear seat cushion. If it was with the fuel pump inside the fuel tank, access would require dropping the tank or cutting a hole through the sheet metal under the rear seat.

Good luck, and tell us the outcome.

 

After some time I finally found the time to change the part. I have ordered an used Fuel Pump Control Module in Ebay. The part that arrived actually was several months older than the part that was in my car. I did replace the Fuel Pump Control Module but still the signs of the problem and the code P1236 are reproducible. Now I am thinking maybe the part I ordered on Ebay is as well broken. But might be as well the wiring problem and need to check that asap. Hope it is not the words case scenario that the fuel pump is begging to go. Is there any way to test the fuel pump? Some stress conditions that I can do to it? I have read the fuel pressure levels several times and they seem to be fine. I did as well buy a new batter thinking that this might be related but not luck.

 

Did you ever get anywhere with this?

 

Unfortunately No. Ended up having to sell the car. I tried fixing myself but I don't have a lot of free time. Some repairs shops I did consult didn't seem to have much of an idea either. They always go for the safest bet, meaning replace everything. Nobody really gets in correct diagnostics. I loved the car every bit though. I'm now in the market for searching for another car but I have to say that I'm spoiled from the Jaguar. Every other car I try ends up loosing in comparison of value and fun per money ratio.

 

Thanks for the reply. I think you are right about the garages unable to do decent diagnosis....

I’m hoping I don’t have to sell my car for the same reasons, I don’t like driving with the MIL on because it’s a bit like the boy who cried wolf, you never know if you’ve got something more serious going on. Also, it won’t pass an MoT inspection with the MIL on.