As soon as I turn the ignition on, the "Restricted Performance" message comes on and reading the codes reveals a P1338 being set. The workshop manual does state that if P1338 code is thrown, the "Restricted Performance" message is displayed as well. I clear the codes, even disconnect / reconnect the battery but this code immediately shows up. The car starts and runs fine. Battery is perfect. State Of Charge (SOC) 100%, State of Health (SOH) 97%. Alternator output is as would be expected.
P1338: Fuel Pump Drive Circuit Low/High voltage.
Chapter 3 of the workshop manual has a pinpoint test for this condition: G251562p4 (page 3290). Basically the test has to do with ensuring the wiring from the Rear Electronics Module (REM) to the fuel pump is not compromised. In running all the steps, they were all successful. The conclusion of the test is that the REM may have an issue.
Seeking any expertise from folks that may have ran into a similar issue. Is an REM replacement warranted? I can get one from fleeBay. The label on the REM does say that this is a programmable unit. Would programming to the vehicle be required? If so, is this something that IDS can do?
I ordered a replacement REM from fleabay. I now have to figure out where I stashed my Windows XP laptop.....
So some additional information: There is another code that is being thrown (it cannot even be cleared) and it comes from the REM:
- P0231 Fuel pump secondary circuit low
Cannot find a pinpoint test for this condition in the Powertrain manual. It is not described in the Jaguar On-Board Diagnostics V6 and V8 Engine Management document.
If anyone knows anything about this code let me know.
Now, from what I read, the REM controls the primary fuel pump and the secondary fuel pump is controlled by a separate fuel pump module which sits besides the REM (confirmed). Even though I have not seen this explicitly mentioned anywhere but deduced by following the pinpoint test for the P1338 code, the pump controlled by the REM is the one located in the right hand side (passenger side for LHD vehicles) and the "secondary" pump controlled by the fuel pump module is the one located on the left hand side (driver side for LHD vehicles).
The question is whether P0231 refers to the secondary fuel pump and if so is there a test procedure somewhere that I missed.
So I was trying to hook up the oscilloscope on the PWM terminals of the "primary" pump to see what kind of waveform the REM is sending and was getting nothing. Getting flustered thinking it was my equipment, I disconnected the fuel pump and attempted to start the car. The car started and idled just fine. I did not expect that. The car will run on one functioning pump.
So I was trying to hook up the oscilloscope on the PWM terminals of the "primary" pump to see what kind of waveform the REM is sending and was getting nothing. Getting flustered thinking it was my equipment, I disconnected the fuel pump and attempted to start the car. The car started and idled just fine. I did not expect that. The car will run on one functioning pump.
More diagnosing on the way....
231 is an open. if there’s no output from the rem the driver is burnt.
you also have the wrong pumps in your car from a 540i so it’s probably been cranking duty cycle up to maintain rail pressure.
231 is an open. if there’s no output from the rem the driver is burnt.
Correct, I just confirmed that. There should be a 12v steady with the ignition on w/o the car running between the read and yellow wires with the fuel pump harness disconnected and there isn't. On pump #2, there is a 12v signal.
That confirms the REM is toast.
I might open it up to see what I see.
So in anticipation of the arrival of a replacement REM unit, my understanding is that you would need to read the configuration information from the old module, install the new module and write the config to the new module. I have not done anything like this before and was wondering if anyone has any info on how to go about it.
I have SDD v. 1.3.1 on a dedicated Windows XP, which I have not used in years. Quite honestly, I prefer the Autel Maxisys for normal troubleshooting sessions. I dusted the laptop off, hooked my genuine Mongoose JLR cable and was able to connect.
Looking and playing with all the options it was not clear where to navigate to read the config data from the REM.
Successfully connected SDD 1.3.1 to my car Module presence retrieval
I went through all the menus shown on the bottom of the screenshot but nothing relevant popped up.
Clicked on the "coded" icon on the upper left corner thinking that is where I need to be for module configuration but was stopped by a password challenge which I have no clue what it would be
If anyone can point me to some information on how to proceed with retrieving the REM configuration it will be much appreciated.
I got the replacement REM the other day. Identical in all respects to the original one. I installed it and as soon as I connected the battery, the car alarm went on which was pretty deafening. The key FOB did not work to shut it down. Eventually the alarm goes off but if you open a door then it starts again. Its as if the vehicle is armed but there is nothing you can do to disarm it.
Armed with SDD v.1.3.1 and original Mongoose cable I struggled through to figure out how to program the "new" REM. I was getting no data from it. Eventually, I faked an electrical problem issue with rear taillights being inoperative. Finally, the "Extras" tab options appeared, and one of the options was program the REM. I selected it and went through the module programming and it came back successful. I was able to then get codes from the REM. Mind you, the alarm issue was not resolved - evidently there is something else that needs to happen to "fully" program the REM to the vehicle so that the alarm does not go off. If anyone has any clue, post or drop me a line... PLEASE! I would be willing to create a thread with SDD screenshots on how to go about replacing and properly program a module in an X350 vehicle.
Back to the original problem: Once I got the REM sort of sorted out, clearing and re-reading codes, I realized, to my horror, that the P0231 from the REM came back! I immediately went back to the schematics and realized the crucial diagnostic step I missed like a rookie.
Refer to "2004 model Year Electrical Guide" figure 03.6: Connector CR73 that plugs into the REM has 4 wires. B+, ground and the 2 signal wires that create the PCM signal to the fuel pump. What I did not do is figure out whether there was power on the B+ wire (CR73-1, brown in color). Well after realizing the mistake, I probed that wire with ignition on and realized it was dead. I went to fuse F33 in the rear power distribution box and sure enough the fuse was burned.
I quickly put back the original REM back (could not stand the alarm going off) and a fresh fuse. I ensured I had signal coming in. I plugged all the connectors and started the car.
Within seconds the fused popped.
My assessment now has changed. The right side pump has an internal short that causes the fuse to pop. Next step is to replace the fuel pump.
Thank you for reporting.
Confirms again that reprogramming is not trivial, even with the good stuf (VCM and SDD)...
I call it tribal knowledge! I spent hours searching the forums and general internet. Some posts lead you to believe that some folks have figured it out but details are not there.
So the original pumps are Pierburg 7.28177.01 and are rated at 170l/h @ 3.8bar and the p/n is specific to Jaguar vehicles according to searching this forum.
I can get a pair of Pierburg 7.22013.69.0 that are rated at 170l/h @3.5bar and are built for BMWs (according to the AI search). The physical dimensions are identical.
Finally finished some other projects taking my time and now I am back on the XJR. Unfortunately, this is not quite resolved yet:
I obtained two new pumps:
- Pierburg 7.07795.17.0 (pump P1)
- Pierburg 7.22013.69.0 (pump P2)
I installed P1 on the passenger side assembly and P2 on the driver's side assembly.
The car started but the P0138 fault code was back. Also a new code appeared P0193 - Fuel pressure circuit high.
I hooked up the scanner and monitored fuel pressure. The pressure was pegged at 70PSI without variation.
I then hooked up circuit amp draw testers on the fuse 24 and 33 slots in the luggage compartment fuse box. Fuse 24 controls the driver's side pump and fuse 33 controls the passenger side pump. The following observations were made:
When both pumps are connected:
- Passenger side amp draw: 6.2A
- Drivers side amp draw: 2.7A
- Fuel pressure: 70PSI
When passenger side is disconnected:
- Drivers side amp draw: 2.6A
- Fuel pressure: 43PSI
When driver side is disconnected:
- Passenger side amp draw: 6.1A
- Fuel pressure: 70PSI
When engine is off, ignition on the passenger side fuel pump continues to run at about 28PSI with a 1.7A draw.
Two possibilities here: Somehow the REM is not properly regulating the passenger side fuel pressure (via the PCM control), or the pump is defective or not correct to this vehicle.
Obvious next steps is to swap the pumps (this is a royal bitch especially when you put the assemblies back in the tank and struggle to connect the 3 fuel lines from the passenger to the driver's side) and see if the REM is at fault and if so, swap the REM (I have a spare one - still need to figure out how to program it to the car)
I confirmed today that the pressure is actually high and a code is thrown (P0193) when both pumps are energized. The scan tool maxes out at 70PSI. The analog gauge I attached to the fuel port on the fuel rail hovers around 85PSI which is too much.
No, I think the fuel pressure sensor is doing its job correctly. I believe the REM is bad and is failing to regulate the PCM signal to the pump to drop the pressure appropriately. This theory supports all the data that I have already collected. My plan is to install a spare REM, and see if I get any different behavior. What I also found out is that pin point test G251562t23 fails. There is a signal coming out of the REM fuel pump drive circuit under circumstances where there should not be one. The corrective action of that pin point test is to replace the REM.
If you pull fuse F30, 10A, in the rear fuse block you can disable the alarm siren. It will also prevent your alternator from charging, but that shouldn't be an issue if you're just trying to program things.
