Ok, bad news I guess. Pinpoint test A says I should replace the ECU. Is that expensive, I can't afford much more right now but, need to drive this baby. My backup doesn't have AC and it is hot in St. Louis this time of year. Can someone please give me some info on my choices? Thanks!

 

rjcl, you have a few options, the question is how fast you need it back and how much of a risk are you willing to take.

If you look on e-bay. they have the ECU/ECM's for $50 or so. The trick with this is you need to find one with a build date close to what your car has. It seems that there is some sort of check that occurs and if things are not just so, it will shut the car down and not allow you to start your car. This can be overcome by having the dealership reflash the ECU/ECM. But, now you are looking at an hour of shop time at the dealership in addition to the price of the ECU/ECM.

Option 2 is to pull the ECU/ECM out of the car and send it off to have it repaired. What this would cost is hard to say. Again on e-bay, people are offering this service for $100. But, keep in mind that for the time the ECU/ECM is removed from the car, it will not be driveable, so, you will be stuck with your back up car. This should prevent the need for getting the ECU/ECM reflashed. But, it may still be a possibility. You would need to talk with the repair place to see if they will be able to transfer your car's data to the repaired unit.

 

Thanks Thermo!

To start with, the car is not driveable now so that sucks but not an issue if I can avoid the dealership cost and towing it 50 miles. The heat sucks but I will survive.

How do I find the build date of my car? Are they all built in the same factory and how close to the build date do I need to be? Do I need to worry about options such as automatic transmission and other things for a replacement ECU? Could there be something else wrong that killed the ECU?

Does anyone have any experience with ECU repair places? If so who, their contact info and approx cost.

Thanks again to everyone who helped me track this down. I wish it was a better outcome but, it is what it is.

Rick

 

rjcl, I am not aware of any time frame that the computer needs to be built within. I think it is more a series of cars as the manufacturers tend to use the same factory to build multiple lines of cars. So, they may crank out say 5,000 of an X-Type then turn around and use the same lines to build 4,000 S-Types, then re-tool the line again to build another 6,000 X-Types. Very few lines are built to only make 1 type of vehicle (only ones I am aware of are the lines for building F-150's (even then, some times they are reconfigured to do say Expeditions) and the Chevy Cruze at the plant in Ohio.

As for potential problems that take out the ECU, the most obvious is the fuses to the ECU. There is more than one. Are all the fuses good (if you need a list, let me know)? After that, a quick look over of the wiring harness to make sure that none of the harnesses are damaged by sharp metal edges, someone splicing into the harness and making a bad joint, improper repair following an accident where the wiring bundle got pinched, etc. After that, any sort of electronic box will fail over time. The length of time is dependent on how good the electronics were made and how much heat (either by ambient or through high current loads) the box has been exposed to during operation.

 

A list would be helpful, I would appreciate that! I just hate to think of spending more money on this car right now. I spent 1000 on keys and fobs, 1000 on tires and was hoping to spend a little to get the AC to cool better and then enjoy it for a while.

 

rjcl, you want to check the following fuses:

-F32 under the hood
-12 VDC at pin 2 of relay R18 (remove relay, look on underside of relay, the posts will be numbered, make sure that you match up the pin on the relay to the spot opened up in the fuse box, check that pin to ground)
-F37 under the hood

By checking for 12 VDC at pin 2, you are also proving the inertia switch is good in the car.

If you need anything else, let me know.

 

Thermo, I have an R1,R3, R6, R7, R8, R9, R10, and R11 but do not see an R18 if you meant R8 pin 2 does not show 12V with the key off or on. The fuses you listed checked out ok.

 

Where does the relay power for pin 2 come from? If it is relay 8. If it is relay 18 where is it? Sorry this is driving me crazy. If I do have to replace the ECU then so be it. I just want to do it the right way so I have no more problems and can enjoy the jag I have waited 40 years to own.

 

rjcl, Relay R18 is under the dash of your car, not in the engine bay.

 

I found relay 18 but no power on pin 2 with key on or off. Now what?

 

R18 should close when 12V is applied to pin 2. This should happen when the key is in RUN position only.

You should be able to feel R18 close when the key is rotated to the run position. If not, the inertia switch may have tripped open.

 

I will check that when I get home but if the inertia switch is tripped it will not start will it. It runs but terribly. You can't really drive it.

 

I tried that and I can feel the relay click when I turn on the ignition and click again when I turn off the ignition. It is likely the ECU, Any ideas on a reliable inexpensive place to get one that will work in my car without going to the dealer would be great.

 

How about an auto salvage place? What problems could I encounter other than it doesn't work on my car? and then I return it.

 

Tharmo, I see my ECU was made by Denso in Spain, I don see the build date, but under bar code I saw the first six numbers said 042004,,,,My X-Type was 04, so what are the next code that tell the day and month? The black box on top of ECU have the date code of 4E02, Date?

 

Thang, The 4E02 is most likely that the computer was built the 2nd week of 2004. That is a fairly common data coding setup.

 

Thermo, the number 4E02 is on the black box connect to five plugs of inside wiring harness that piggy back with the ECU, it not on the ECU, there are bunch of numbers on the ECU sticker, can you tell me which one is the build date, and what is that to do to have one close to my ECU build date?Thaks

 

You know if you just swap the "ECU" (seems to be the PCM) the car is liable to go into anti-theft and need dealer work?