I have a 2004 jaguar, S-Type, V6, 3.0L, with about 40,000 total miles on the car. It has a fuel tank with one main electrical pump and a siphon transfer pump. Initially I drove from home to the city which is about 15 miles. While I was driving around the car just immediately stopped, shut-off/died at a red light. I tried cranking it several times but it wouldn't start. The car cranked real fast and strong so it didnt sound like anything was wrong with the battery. There was no "check engine" light or nuthin. Eventually I had it towed home. Got back in the car a few hours later and the car cranked up as if nuthing ever happened or was wrong. It did have this "Restrictive Performance" message on the dash, which apparently means the problem could be a number of things. The next day I drove the car and after about 5 miles it did the same thing just immediately shut-off/died while driving. This could be dangerous if U were on the highway driving 70 mph and the car just suddenly dies. I left the car a few hours, came back and car again cranked up as if nuthing ever happened or was wrong. It did still have this "Restrictive Performance" message on the dash. So I drove the car home quickly before it could shut off, I hooked my scanner up to the car but no codes except P1000 (which is nuthin). So this time, i cranked the car up and let it run until it died, then the DTC codes were P1338 (Fuel Pump Driver Module Communication Circuit, Fuel Pump Driver Module) and P0191 (Fuel Rail Pressure Sensor Range Performance). The next day the car started again so I connected a fuel pressure gauge to the schraeder valve on the fuel rail, and just let it run until it died. As the car started shutting down, I could see the fuel pressure decreasing the same time from about 52 psi down to almost zero. So I'm assuming the car died because it lost adequate fuel pressure. The car wouldnt start so I began diagnosing the problem. I check the fuel pump relay (R15), the fuse (F47) for the Rear Electronic Module Module/fuel pump driver (REM), power to the Fuel Pump Diode and the hot wire from the REM to the pump was good. I did not check the ground wire from the REM, so I'll have to do that because I think the REM activates the ground to operate the pump. But all items tested good. I assumed the actual fuel pump diode was good since the vehicle does start up after it sits a while. So with the car in the died/shut-off condition, I turned the ignition switch on to see if the fuel pump runs, but it does not. So I took out the fuel pump assembly and tried to hot-wired the pump motor from the pump connector side of the harness fitting, but the pump wouldnt run no matter what combination or how i switched the electrical probes. So even though this was the case, I didnt think the connector was bad because the car would soon startup in a few hours. So i hot-wired upstream of the pump connector and the pump motor ran, so it appears that the pump is good. So now I'm thinking that something is stopping a complete circuit to occur (power and/or ground) from getting to the pump motor and that item would be the REM. So I'm thinking my diagnosis is that the REM (which I dont know how to check) is faulty/bad. CAN I GET SOME FEEDBCK ON MY DIAGNOSIS AND ANALYSIS? ANYBODY HAD THIS PROBLEM AND RESOLVED IT? AS OF NOW I CANT EVEN DRIVE THE VEHICLE BECAUSE I DONT KNOW EXACTLY WHEN IT WILL DIE.

 

i was going to say it sounds like the pump is getting hot and shutting off. the manual says
6.21.3 Primary Fuel Pump Circuit High/Low Fault
The ECM also receives the following flag via the CAN bus from the rear electronics module:
• Fuel pump monitor line open circuit.
• Fuel pump monitor line short circuit to battery.
• Fuel pump monitor line short circuit to ground
If any of these flags indicate a fault for longer than a set time, then a fault is registered and P1338 is logged.

 

Lots of good details and troubleshooting so far, but it looks like this little bit sent you off into the weeds. In the immortal words of Douglas Adams: "Don't panic!"

Check out the wiring diagram here, figure 03.2:

http://www.jagrepair.com/images/Auto...x2062004en.pdf

Note how power to the pump passes through the RECM first. The circuit to the pump will not have power until the RECM is commanded to run the pump. Basically, you can't jumper power to the pump via connector FP2, which I believe is the connector you mentioned. This connector has 3 other wires which is for the fuel level sensors, as seen in figure 07.1. No matter how you played with these five wires, you won't be able to hot-wire the pump from there.

So hold off on trying to make the pump run for now. Think about probabilities. If a component had failed, your choices are the pump or the RECM. In my overinflated opinion, electronic modules are usually VERY reliable. The pump? Not so much, with all those moving parts to wear out. If I had to shotgun a part, I'd certainly try a new pump before even considering the RECM.


More details about your two fault codes here:

http://www.jagrepair.com/images/Auto..._OBD_II_R2.pdf


P0191 points to low output from the pump, which you've already confirmed. I'd call that code a secondary fault, not the root cause. P1338 lists the pump as one of the possibilities. Given the chance to spend your time and money, that's what I'd suggest first.

By any chance has the car been sitting for a while? These fuel pumps are notorious for misbehaving if sitting inactive for several months or longer.

 

No, the car has not been sitting for a while, other than the time I've spent trying to diagnose it. I've looked at Figure 03.2, but not 07.1 . I did look at the Jaguar Workshop Manual S-Type 2002.5, and it shows the Fuel Pump Harness Connector with only four (4) wires identified as: Right-hand fuel level sensor signal supply, Fuel Pump voltage supply, Right-hand fuel level sensor voltage supply, and Fuel pump GROUND supply. This is the same setup as my vehicle fuel pump harness. So I assumed that the Fuel Pump voltage supply and the Fuel pump GROUND supply would be the two wires I needed to hot-wire for the pump. It seems that assumption would be correct, or why wouldnt it? U mention five (5) wires but there are actually only four(4) wires at the harness connector, and only four (4) wires inside the actual pump assembly housing: two (2) wires fed the level sensor and two (2) wires fed the pump. I guess somehow I need to put figures 03.2 and 07.1 together to figure how the pump wiring and sensor wiring work together with only four (4) wires. Note that I'm only talking about the tank side that has the electric motor pump assembly and not the transfer fuel side.

If it is the fuel pump, in your opinion and/or your experience, do U have a preferred pump brand and model that I should use. My intent is to only purchase and replace the pump, and not the entire fuel pump & housing assembly. PLEASE PROVIDE FEEDBACK.

 

Hot-wiring the pump won't work like you're thinking, not from that point in the harness. Those two wires go directly to the RECM. The RECM only supplies power and ground to the pump when commanded to do so. At other times, those wires are inactive. You would have to trick the RECM into thinking it's time to run the pump. You MIGHT be able to do this for the initial pressurization of the fuel rail, before engine start. But even that command only runs for about two seconds.

That's in theory. On a practical level, I'm not sure all this hot-wiring attempt is worth the effort. You know the pump has recently run at some point. The pump has not totally failed, but the issue is the pump is cutting out intermittently. Is it the pump itself? Is it the command? There's no reasonable method to prove what exactly is the root cause. Even if you were to successfully hot-wire the pump, it doesn't solve the intermittent nature.

Also, hot-wiring the pump causes it to run full time. The pump normally operates on a Pulse Width Modulation (PWM) basis, where the RECM rapidly turns the circuit on and off to modulate the pump output. In effect, PWM reduces the input voltage, if you were to average out the chopped signal as seen by the pump. Operating at full voltage is actually easier on the pump, strange as that may seem. The pump works harder on reduced voltage. So you could go to all that work and figure out some way to hot-wire the pump, but not really stress it hard enough to fail. A marginal pump could still pass such a test, and give misleading results.

Once again, this is all theoretical stuff. After some point, if you don't find a smoking gun pointing to a fault, one realizes you can only troubleshoot so much. You've just to make an educated guess and try something. Is the pump bad? Heck if I really know, nor does anybody who insists otherwise with what we know so far. But you've got to try something, and the pump is the most likely culprit. Most of the time, troubleshooting leads to a nice tidy gift-wrapped answer, but not always. Sometimes it just leaves a burning paper bag full of dog &#!+ at your front door, and your only choice is to stomp it out. However, I'd still be super cautious of trying to over analyze the problem, especially when a new pump is not an expensive gamble.

Sorry I can't help you with what brand to purchase, etc. One caution, stay away from the no-name brands you'll find on eBay. The reliability is very poor. Same with the house brand at discount part chains. Go with a reputable name brand. Hopefully somebody else can chime in with what has worked for them.

 

i took a chance and replaced the fuel pump and housing assembly (which was $302), couldnt find pump motor only to purchase. Ahyhow, the pump/car still runs about 20-60 minutes then car dies, so nothing has changed. My scanner only shows codes P1000 & P0191 (Fuel Rail Pressure Sensor Range/Performance). Car appears to die from no fuel pressure since the pump has stopped, so I assume code P0191 is being flagged because the pump stopped resulting in the fuel pressure died. Turning on the ignition switch does nothing and does not acivatethe pump, but if i put power (i.e. hot-wire) to the pump wiring, it works. So maybe the REM is dropping/losing the command to run the pump? If it is the REM, any idea why it would it operate the pump for 20-60 minutes, then shut it off. And then after the car sits for a while (few hours or so), the ignition switch all of sudden now activates the pump and the car runs. The REM doesnt appear to be getting hot (at least not from my hand touch). I hate to just replace parts, but my only other thought is REM (used from Ebay) replacement. I'd hate to think it could be the ECM command!! FEEDBACK?

 

I believe theres a relay for the pump. Ive seen relays go bad. Might want to swap the relay out with a new one because I’ve seen times when relays work for a bit then open up after a while because They get hot. I don’t know that I would start looking at different engine command signals that control the operation of the fuel pump using SDD or some other program that gives you the ability to monitor singles well the car is running I just figure out what’s single is opening up or shorting out because something is definitely telling it to shut down
I wonder if something with the security system might be shutting the pump off so you could look at your alarm triggers as well

 

R15 in the rear fuse box

 

Well, bummer. I thought you could replace just the pump ($50?) and not the whole assembly.

I'd certainly try the relay, as previously suggested. Have you swapped it with a known-good relay from another system? I could have sworn you had already tried that, but in your first post you only mentioned that you checked the relay. If not, I must have been thinking of another thread. The relay would have been the first thing to try, sorry if I fed you bad info.

 

When I had this exactly same problem.with my car the scan tool did not have a code. The only indication where the problem was REM "voltage out of range". If you look at the rear lights you may also find that they do not work when they are turned.

There are a long list of pinpoint test for the REM in the manual but watch out because suddenly they go wrong when they say no they mean yes. You will see when this happens the manual does not make any sense.

You can get the manual from.Jagrepair.com

If you need to replace the REM make sure that it has the same serial numbers. I did not have to reprogram it when I replaced mine from ebay

 

Hey I know this is an old thread but I’m wondering if OP ever got this resolved and what it was? I’m having a similar issue with p0191 and not getting anywhere.

 

It has been just about four years since the OP's last post. Pretty "iffy" on a response.

You might want to send a PM; hover your cursor on his name, click and a drop-down menu should appear.

 

Not sure if I missed it, but was the fuel filter replaced? Also, my XJR has 2 pumps. Perhaps the in tank filter is plugged?

 

If you have not fixed your problem it may be the PATS system preventing your car from starting. When you put your key in the ignition and turn to run the light might blink fast for 60 seconds after which it will blink a code like 1_6.

 

Thanks for the info but no offense idk how you plan to offer help if you don’t read the issue and know what’s going on. So many people post just to post and it can steer people way off. OP and me said car starts but has fuel pressure issue issues and related codes so it’s not PATS.

Update for everyone, it was the fuel pump. Car runs great now. Tell tale sign was when I removed rear seat and could see the padding was already moved out of the way and some tabs on ring cover were broken. The p0191 really threw me off though.

 

If you have not fixed your problem it may be the PATS system preventing your car from starting. When you put your key in the ignition and turn to run the light might blink fast for 60 seconds after which it will blink a code like 1_6