To add to JagV8 - possibly the PATS is not recognizing one (or more) of the reflashed modules therefore immobilizing the car/fuel pump...

 

From what I understand all the modules need to "read" each other... If not, the car is essentially "bricked"...

 

If that were the case, wouldn't the PATS indicator flash something?

If I turn the key to Position II, the PATS indicator comes on for 3 secs then goes out, which I believe is the system checks OK signal.

Unless I misunderstood the PATS explanation, if PATS was immobiliziing the car it would flash a code indicating that it is doing so.

 

With little options left, I tried the "Immobilization Setup" which ran fine, but alas did nothing to bring the car to life.

So the only thing I can think to do now is Re-Flash the ECM.

If anyone has a 'don't do it!' now would be the time to chime in.

 

I can't see any point in reflashing the PCM. You don't appear to have any PATS problem or indeed any PCM problem.

 

I'm surprised to see you say that. At this point, the only thing there seems to be is an ECM problem.

Since the EMS relay or diode failed, it's never started, there are now no outstanding DTCs, no network issues, etc.

For some reason the ECM is sending the 75% Fuel Pump OFF signal to the REM, but after reading everything I can get my hands on, if all was normal the ECM wouldn't do that without throwing an DTC.

When the EMS relay failed, and if it failed while the car was running or the ECM was active, isn't it possible that it could put the ECM into a confused state?

I'm all ears if anyone has any other suggestions, but at this point I'm at wit's end.

 

Wish I had the answer...

I am wondering, if the ECM is actively telling the REM not to run the pump (with this 75% duty cycle signal) then is it a software/firmware/comms issue? or hardware related? Given that there is communication with the REM then it seems like it's doing this for a reason. If that reason is a corrupt program in the ECU (maybe? I don't know) or if there is an external factor that is causing the ECU to prevent fuel getting to the engine (why I asked about the inertia switch).

Try the old "hard reset" by removing both cables from the battery and touching them together?

Failing that then I guess i'd try re-flashing the ECU...

I'd also be tempted to put 12V directly on the fuel pump and try starting the engine, just to see if it would work...

 

Thanks for the kind words on pm but damn "start at page 3 and catch up"? You have gone through so much crap i dont even know where youre at. And this is the exact issues i avoid on here because it heavy diag. Which takes tons of thought, and time in diagrams, checks etc. But where i would start is 2 fold. Er maybe 3. 1 if you have a red x on sdd that module is not communicating period. Check power and ground at the module with a dvom. Then check network resistance(you do know you check resistance with battery disc right?) then voltage with battery hooked back up. iirc you have a high and low leg and voltages should add up to roughly = 5volts.take apart and clean bulkhead pos connector, this issue has caught me a couple times even on mine. Remove the fuel pump relay and jump it on 3 and 5 with a 10-12gauge jumper you can make with spade connectors. This is a fast and dirty diag check. If it fires you know everything is functioning except the fuel pump to run signal then you can isolate your diag to just that issue period. Sounds like youre throwing too many trees into the forest to me at this point. And maybe i missed it but you still have a red x on ecm right? This is the issue to focus on for the most part but jump the pump

 

For clarity, and hopefully to make it easier for everyone, let me summarize the present the state of car:

1. Cranks normally, but won’t start

2. MIL Red light on, but no corresponding message on Message Center

3. Original fault that caused all the ECU, Network, and numerous fault messages, and the no crank, stuck in park, etc., was a failed EMS relay or diode, this was addressed by replacing the Engine Bay Fuse/Power Distribution box. However, this fixed everything EXCEPT the no start.

4. Prior to the EMS relay failure, car ran beautifully with no issues.

5. IDS/SDD now communicates with all modules including the ECM.

6. Battery is new, fully charged over a couple days, and kept fully charged.

7. Cleaned and inspected all ground/earth points, harnesses connectors, etc.

8. Tested every fuse in all three locations

9. With No Start symptom selected, There are NO related DTCs.

10. If you attempt to start the car, DTC P1582 will get recorded. Which is for the Flight Data Recorder. Looking at the recorded data, it looks like it is merely reporting that car failed to start.

11. Unrelated DTCs are few, minor, and unrelated. For instance “Drivers Seat vertical motor memory position out of range” or “Audio CD internal fault”

12. There is one DTC in the “unrelated” that I can’t identify:
DTC ECU Description Relevance
U3FF6 REM “no description available” 0%

13. Re-flashed REM and IP

14. Ran “Immobilization Set-up”

15. After doing or changing anything, I’ve always done a ‘hard reset’ by removing both negative and positive cables then alligator clipping them together for 10 or more minutes.

16. I spent quite a bit of time last night using the DataLogger feature looking for anything out of the ordinary. For instance, I know it has been reported that TPS out of range signals can screw things up, but they all measure within tolerances and react to throttle movement correctly.

17. The only signals that I can find that would cause the issue:
Fuel Pump Duty Cycle to the REM - 74.9%
Modulated Fuel Pump Duty Cycle - 75%
Which in ECU language is “Turn the Fuel Pump Off” from the ECM to the REM.
And because the fuel pump isn’t operating, and after many start attempts, there is no fuel pressure at the rails.

18. It looks like the coils and injectors are getting powered (12+V at Fuse30 and 13).


I am stumped.

 

Thinking out loud: #3 - are you sure all the connectors to the front distribution box are fully seated and connected? And is that EMS Relay/diode tested good?

 

And...

No 10 - Have you cleared the Flight Recorder?

 

I believe I was diligent in reassembly, but it's not a bad idea to for me to perhaps double check that.


Yes

Yes

 

Did you try this yet?

So there may well be an issue with the REM... getting that weird code + the REM not running the fuel pump, coincidence? If reflashing did not work, then it might be a hardware issue with the REM? Just thinking out loud...

 

Haven't had a chance yet, but I don't believe I can do what Brutal suggested because the Fuel Pump Relay is a "Nonserviceable PCB Relay", and according to the schematic it is in sequence prior to the REM. The relay feeds power to the REM, and the REM decides whether to feed power and ground to the Fuel Pump.

I have tested that power is getting to Fuse 33 (Rear Fuse Box), which translates to the relay operating properly. (unless I'm reading the schematic wrong... it's page 61 of the 2004 MY XJ Electrical Guide)

EDIT - Looking at the schematic I can't exactly tell how I would hot wire the Fuel Pump, I'm not sure which output is being pulled to ground by the REM

 

Uh ok so now i notice youre posting in the x350 section and youve been talking about your 04 not the 95 i thought.. i never look at where im at....lol

 

I would just get the Jag towed to the dealer, and be done with it.

 

Not particularly helpful...

 

abonano,

I thought for sec you'd be the hero, but yesterday I had a chance to look at the Front Power Distribution box. I did a full R & R, and since it was a used unit, I double checked that there were no broken pins or failed connectors or any corrosion. Then made sure there was a positive seating of each connector.

No joy.

 

oh well, it was worth a try...

 

Perhaps I should take a different angle on this.

Pretend that REM is fine, and is doing what the ECM is telling it to, and the ECM is fine. Therefore a signal is going to ECM that makes it decide to shut off the fuel pump.

Does anyone know all the signals (or lack of signals) which could tell the ECM to shut down the fuel pump?

Crank Sensor? Inertia Switch?

Thanks