Hello All,

As happens every 6-12 months my 2002 XJR throws a hissy and I need to fix her again. In the past I was getting “gearbox overtemp fault” regularly. I ended up replacing the electronics plate in the transmission above teh valve body, and that seemed to really improve that. Still got the odd error, but not on a daily basis.

The Jag has been running well for a while now, so I knew the time was close. Especially when I had thoughts like “Wow, this car rides so nicely. She’s so quiet, and the doors still close with a solid thunk. I love the power she has. I should really keep her long term……”

Over the last couple weeks I have noticed a “restricted performance” pop up and go away after a few seconds every now and then. Last week I was picking the kids up from daycare and when I went to start the Jag the engine just turned over but would not cough or sputter at all. Stopped cranking after 3 or 4 seconds and tried again and she fired right up and everything seemed normal. She always starts as soon as you turn the key……

Today on the way home from work she ran rough for a second at a light and I looked down and saw the “restricted performance”, but then it cleared up again. I picked up the kids again from daycare, and when I went to start her, just cranked, no cough or fire. The fuel pump does not run when you turn the key to “ON”. I tried pulling the primary fuel pump relay to default to the secondary pump, but still no cough and no fuel pump running in the “ON” position. I reset the inertia switch with no joy either.

Several messages scroll across the display with the key in the “ON” position:

Electrical Fault
Suspension Fault
Restricted Performance

I pulled the codes and get:

P0351
P1230
P1647
P1671

I tried clearing the codes with the scanner to no avail.

I tried removing the battery cable, to no avail.

I’ve started searching on the faults, but any help to get me to the source more quickly would be greatly appreciated.

Thanks,

Mike

 

I have the RP message come on and off sporadically, it is there and gone then next time I drive and won't reappear for several days driving. Took to the dealer 3 hours =$450 and they tried to clear many old codes and look at things. Battery is new, grounds are clean.

He said I have an aftermarket supercharger cooler pump. I know the connector is broken( anyone know where we can get connectors to replace broken ones?) but I cleaned the contacts and it still is sporadic.

Did have a small leak from that multi headed 1" cable that clips on the back of the expansion reservoir and noticed a small leak on the inside where it clipped to the expansion tank. Didn't know what I was looking at and heard the tanks crack at the outlet. Replaced the expansion tank ( Ebay ) for about $160 purchase cost and installed myself. Turned out O ring on the inside was bad and replaced that ( ace hardware) and took care of the leak issue. You don't have to buy the whole hose assembly for $60 or whatever the cost was. Have a write up on that somewhere on the site..2004 xjr

Don't think the pump is the problem but bought a used one and will install. The only weird thing I could guess, since the pump runs and the supercharger and car don't overheat that maybe there is a voltage or amperage difference from stock. Assuming it is aftermarket as the dealer says- I don't believe, but don't know it to be true yet, that maybe the computer module picks up and reads out of spec voltage and amperage and treats that as a fault?

This intermittent RP fault has been ******* me for a year. No rhyme or reason as to it coming on.

There has been reference to some hidden under the supercharger piece that leaks. I swear at times I smell coolant, but haven't noticed any real change in the level or leaks on the ground. You need the orange coolant( ford) when you take the stuff apart.

 

Codes are in workshop manual - free download and may also be on JagRepair.com - Jaguar Repair Information Resource

Because P1230 says fuel pump problem I think I'd go for that first.

P1647 if still there you have an O2 sensor fault.

P0351, probably last to do.

Not sure what P1671 is.

 

To be specific, P1230 refers to a fuel pump electrical circuit problem, like a relay - on the number 1 (primary) fule pump.

You might swap cylinder #1 ignition coil with another top chase the P351 code.

 

Thanks for the replies so far. My code reader gave me descriptions for some of the codes, and I can look up the rest. I was hoping for some advice on troubleshooting.

I’ve had the O2 code for a while, it’s just the heater on the front driver’s sensor, doesn’t affect running, forgot about that one. Keeps my CEL on also.

I’ve also had the ignition coil fault before also and had to replace a coil. That just gave me an intermittent rough running when the coil quit firing the plug on a single cylinder. It didn’t cause a complete refusal to fire.

Also, I had to replace both pumps before. That was the worst job I’ve ever had to do on any car; even pulling the engine and trans on my 300ZX and doing a full twin turbo swap was significantly more pleasant. That’s why I pulled the primary relay to default to the secondary relay and pump. Again, there wasn’t even a cough of a sputter this time (there was when the fuel pumps died).

I will point out that all the other times I only got codes when I hooked up my code reader. This time the dash display is scrolling codes when the turn the key to “ON”. I have never seen the “electrical fault” code on the dash display before. I think there is something more far-reaching going on this time, and that was I was hoping for some insight on.

I plan to try supplying the pump relay socket pin directly with 12V to see if I can get the pump to run, and if the car will start then. Guess I’ll see if I have spark also. Not sure what to try after that.

Thanks for any thoughts,

Mike

 

Not able to help much, other than suggesting you ensure the battery or connections are not a problem.
The o2 sensor can result in the ECU making fuel mixture adjustments that could result in catalytic damage.

 

Thanks RJ. I haven’t gone back and doublechecked the code, but my previous O2 code was just the heater. So the sensor takes a bit longer to heat up like in the old days before heaters. I’m betting that short warmup time won’t cause any damage.

Mike

 

General advice on troubleshooting? Toubleshoot one problem at a time, while keeping the others in mind to see if you can find a common thread. Fix the seemingly easiest ones first. They can mask symptoms or indicate as other problems.

The reason you get CAN bus faults upon hooking up the scanner is that some scanners are not "friendly" as they join the bus. So, as they connect, the token on the bus is interrupted until the bus re-sync. If that is what is happening, and you have no other faults, the CEL will only light as you connect the scanner.

I gave you the cheapest way to diagnose misfire faults. Swap coils and see if the code follows to the new cylinder.

To troubleshoot the pump circuit, you n need a 12 volt test light or a meter. And a schematic. Have you downloaded the electrical prints yet? Do you know how to read them? If not, ask for help and someone will do so, I am sure.

If you have decided that having an O2 heater code does not mean anything except the sensor will be slow to become active, I really do not know how to help you with that.

 

The O2 code tends to mean fuelling will be bad or terrible and may destroy the cat on that side. Just fix it

You may have a battery on its way out. Load test while measuring voltage. Too low and you can get fake codes.

 

Sparkenzap,

Thanks, but it is not a misfire. There is no fire, most likely from lack of fuel since the fuel pump(s) is not running. I’ve experienced misfires on multiple vehicles in the past, including this Jag, and this is not a misfire. If you want to call something in the ECU failing and not providing a signal to every coilpack at once a misfire, then I suppose you could consider this a misfire. Note, I am not saying there is no fire at any of the coilpacks, only that this is not 1, 2, or even 3 coiplacks not firing. There is NO ignition (pressure caused by burning fuel) of any kind on any cylinder. As I said earlier, I believe it is caused by no fuel, not lack of spark. I will check spark tomorrow, however.

The dash display scrolls the codes

"Electrical Fault
Suspension Fault
Restricted Performance”

When you turn the ignition to “ON” with or without the scanner, sorry about not being clear on that.

I was asking for help on what would be the cause of these multiple errors in combination from someone who has experienced them, or perhaps remembers reading a post about something similar. And what I could look to test. For instance when I kept getting my “high gearbox temp” or “gearbox overtemp” error, it wasn’t really a high temp error (it would do it at first start of the morning, even in the 20’s F). I think the problem was either the adjustment of the shift lever (will throw the same P code apparently), or the conductor plate acting up. People helped me to learn that when I posted, and posted the section of the workshop manual for electrically checking the ho-low pin combinations for each shifter position.

I am adept at both mechanical and electrical troubleshooting, and am not asking how to tell if a wire has a short, or if there is 12V. I’ve performed a complete engine swap, replaced engine management harnesses, installed widebands, and all sorts of other electrical devices. I’ve repaired several audio amplifiers by finding and replacing faulty components. I have an amp from a friend on my bench right now for repair. I have a modern digital storage oscilloscope. I have previously downloaded the appropriate schematics when troubleshooting other areas of the car. I’m a mechanical engineer and know how to read and trace a circuit.

I’m looking for the broader issue that is going on that would make the car throw these codes and the fuel pump(s) not function, seemingly almost out of the blue.

Not trying to come off as an ***, just trying to convey that I am not an inexperienced newbie trying to ask “How can I tell if I have power at my fuel pump (or a trigger signal to a coil)?” I’ve got that; I believe there is something larger going on.

Thanks,

Mike

 

Yeah, I need to.

It’s the difficult one to reach though (on US cars), and I read there were different resistances of heaters used at different times on these cars, and if I pick the wrong O2, the code and CEL will stay there. I never could get clarity on the correct O2 (short of buying new OEM for an outrageous price), and since the code says it’s a heater failure only, my fuel mileage hasn’t gone down, and my scanner showing live data and fuel trims looks normal I haven’t really worried about it too much.

Mike

 

OK, I think I understand you now. You are not trying to run down the codes, but instead are trying to figure out a single overriding root cause for all of those faults, right? And while considering all of the info, I missed that it had turned into a no-start!

I believe that the fuel pump issue, which is an open electrical circuit, could be the root cause of the the no start and the previous RP- falling fuel pressure will give extreme lean which will RP an X-308.

The P351 is a misfire. That was my misfire misfire! I guess your main concern with that is that you cannot clear it. I agree that is strange, but I am going on the assumption that in addition to your fuel pump circuit problem, you have a dodgy scanner (see bus faults).

Now, if your assumption is correct, and all (or many) of the problems come from one source, I would look at all of the CAN bus connectors for corrosion. I would read the CAN bus while powered off, to see if you have both terminators in place (110 ohms, I think?). Obviously, the ground straps should be given some consideration. But, I think your current problem is no fuel pump as the code indicates, so I would go after that with the test light or meter.

So, I will remind you what you probably already know. Troubleshooting anything with multiple, seperate, problems can prolong good troubleshooting procedures because they mask each other. Consider that that may be your case.

 

The Jag did run rough for a couple seconds on the way home that day while sitting at a light, so that could have been the misfire that set the code. I just went out and cleared the codes again and cranked the engine, cycled the ignition back to OFF, then to ON again and read codes:

P1230
P1671

So the misfire code appears to be gone. The P1671 is just the O2 sensor, so I guess I’m not too worried about that for now.

Previously during other troubleshooting I checked a bunch of the grounds, the false bulkhead connector up front, engine ground strap, etc, and they were all good. I’m charging the battery right now and will check the voltage before and after I crank the engine, and also try jumping it with a much newer battery in another car.

I will also try powering the fuel pump directly through the relay socket. BUT, what concerns me is the 3 scrolling codes. I don’t remember having those when the fuel pumps died, so I am wondering if that is an indication something more is going on.

FWIW, when I turn the key to “ON”, only the high beam and left and right turn signal indicator dash lights come on. None of the other lights. Shouldn’t every light come on so you can see if a bulb is burnt out? Something odd is going on…

Additionally, when I am cranking, “ASC not available” and “Traction control not available” scroll….. I don’t recall ever seeing that before. They go away once I stop cranking and the “RP”, “electrical fault”, “suspension fault” begin scrolling again.

This is my first CANbus equipped vehicle, and I am ashamed to say I don’t know how to check for the terminators. I’m pretty sure I can see the “traffic” on the network with my oscope, but don’t think it can check for terminators or decode what is actually being transmitted.

I do have a spare ECU, but I’m not so sure it is a plug-and-play swap in this car. Or even if it is reprogrammed, I thought I may have read the serial numbers have to fall in a certain range to work. Any thoughts on that?

Thanks,

Mike

 

Save yourself a lot of grief and read jag's own details of each of the codes. They list each of the known causes for each code.

It's free to download the workshop manual.

Codes like P0351 have not reappeared because - as the same docs show - they need 2 trips. They define that, too.

You're working blind with lots of old knowledge but not reading the new stuff.

P0351 is not exactly a misfire, BTW. Do read the docs!!

You don't have CAN errors do you so why worry about the terminators?

Do not swap any ecu without REALLY knowing a ton more than you do now. You do not want to get the car into anti-theft.

 

Thanks, I have downloaded the shop manual previously. I’ver had this car for 8 years, but it is the newest car I have owned. Everything else is/has been 12v signal wires throughout the car with ~20 wires from the ECU running the entire car. About as complex as a rock compared to this. I have this reoccurring dream of building a 1998 E36 M3 5-spd sedan for my DD. All new bushings, ball joints, vacuum and fuel lines. MCS coilovers. Nice and simple setup, I could fix anything relatively easily. Maybe do an S54 swap running of the OEM ECU down the line…. Drive that for 20 years and be happy.

Back to the XJR:

I cycled between cranking, turning car off and removing key, locking, unlocking, and cranking several times. Only the P1671 and P1230 codes return.

I was only saying that I have a replacement ECU as last resort, I would do a lot more research before plugging it in.

So besides the scrolling codes here is additional information:

The P (or any other gear lights) does not illuminate when trying to start the engine (or ever). Putting the shifter in N (neutral) and the engine will not crank (spin over) at all.

Besides none of the dash warning lights (besides L&R indicators and high beam) coming on in the key “ON” position, I just noticed that neither my cruise nor sport button lights illuminate. Both are always on, and I just tried both of them in IN or OUT positions, and they don’t illuminate.

This is something more than a simple “look up the error code and replace a part”. There is some larger, overarching issue going on I believe.

Mike

 

I was going by memory on P351, but you are exactly right, it is NOT misfire but is the open circuit monitor for the Ignition coil, which is a similar fault to the fuel pump circuit fault, P 1671. My comments about the CAN bus was because of the suspect behavior with the scanner and the fact that there were unusual RP and scrolling messages, like when the instrument panel cannot communicate with the other systems.

So,it seems that either the indicators are screwed up ( the CAN bus, the ECU, or the IP module), or there are circuit problems in the fuel pump circuit and, intermittently the Cylinder 1 ignition and the other circuits mentioned. SO, the main connectors, ground straps and module connectors could all be suspect. Since, as I read the definition of the problems, the fuel pump circuit has now completely failed and will not reset, I would start with that since it should be easy to troubleshoot. The pump shopuld run fopr a few seconds on power on, then again as the engine is cranked. A test light will indicate power to the pump #1 relay coil. The test the power circuit. Or, you could jump the contacts to let the pump run continuously for a test.

 

What errors were they? Ideally you fix them one at a time as they appear. But at the least you probably now want to set those ones aside and see how many things that leaves to see if they could all be one cause (a bad harness maybe). The electrical guide and staring hard may get you there if there's more than a single fault that appeared all at once.

With CAN you have protocol-protected network packets. You're not getting errors about those failing so you have a network that works. That leaves all the rest potentially to worry about...

I take it you have made really really sure your battery does not sag under load because all bets are off if it does. The computers will stand a drop but only so far, then like all computers they fall over messily. (This is also why good power & grounds are vital.)

BTW a 'scope can be handy - most people can't realistically check PWM etc signals but you can.

 

I was getting all sorts of errors in the past. Faulty brake switch was one culprit, and a bad coil pack gave me intermittent “restricted performance” errors for a while.

I forgot the car would do this “interesting” thing of completely shutting down on a hard left turn. Complete electrical system reboot like you unplugged the battery (while moving mind you). It would clear all the trip meter, mpg, fuel used, etc. Took a couple seconds to come back each time. That seemed to go away fro a long time, but the Jag has done it once or twice in the last few months again. Maybe related? Don’t know, but that is not what it is doing at the moment.

Then I was getting “HIGH GEARBOX TEMP” or similar almost every time I would start the car. At first I was banging it through PRDL a couple times at full line pressure (unpleasant) and it would clear up. Then it got where I had to drive farther and farther for it to clear. I pulled the linear switch, cleaned everything without much luck. Finally figured out I could not start the car and rake the shifter from P to 2 several times and it would go away and I could drive the car. I was thinking it was a faulty temp sensor and was going to bypass it with a resistor, then did some reading and found someone with a similar issue that was resolved by replacing the conductor plate, so I tried that. The first start after the replacement the error showed up, grrr. But then it all but went away; happens very rarely now. I think it was probably a cable adjustment issue and removing and reinstalling it to replace the conductor plate got it *just* within specs.

Here is a thread of mine from a couple years ago with some issues if you would like to see more historical info:

https://www.jaguarforums.com/forum/x...-codes-115028/

I think all those issues are resolved. In fact, other than the CEL from the front LHS O2 sensor heater I have not had any codes for 6+ months and the car has been driving fantastically…

I have the rear deck and subwoofer out, so I can hear the pump run when it is operating normally. It is not running, ever, now. No priming when key is ON and no running during cranking. I had my neighbor with his ear at the tank while I did this also to confirm.

I mainly got the oscilloscope for audio work, but being able to use it to look at sensors on my cars and record the data was a big bonus. Crank, brake, speed sensors, etc I should be able to read but have not tried yet.

Plan for today:

1) Battery on charge, will try starting once again
2) Will try jumping with a know good battery in another vehicle
3) Spray starting fluid down intake and see if I get a cough
4) wire 12V direct to fuel pump at relay socket and see if pump runs/car will cough

Thanks,

Mike

 

No change after charging.
No change after jumping with known good battery/vehicle
No cough with ether sprayed in intake

 

OK, here is a pic of the dash as soon as the key is turned to the “ON” position. Every light should be lit up like an Xmas tress, but as you can see they are not:




I also checked to see what will work and what will not.

Things that DO work:
fog lights
high and low beams
turn signals and hazard
horn
mirrors
wiper
clock
radio and antenna mast
windows
interior lights
12V lighter socket (only checked front)
the tach moves up slightly when cranked (so it seems to be functioning)

Things that do NOT work:
No power to HVAC system (no lights on buttons or temp display)
cannot check trip meter, etc because of codes scrolling
no lights on gear selector J-gate
no lights in cruise or Sport button

Any ideas? I’ve been researching, but no silver bullet yet. I thought maybe dash pack, but the symptoms don’t seem to line up with those I’ve found online.