My 2001 S-Type V8 Automatic is having a head scratching issue. It's overall a crank/no start issue I'm seeing that's including PATS I believe. Here's that backstory of the car when first obtained: The car was bought being told it starts sometimes but mostly won't start. When I showed up my initial thought was the battery of course (had 2 x-types before, I'm aware of battery issues). Using jumper cables to the unhooked battery cables, got the car started after 2 attempted starts, cool, and unhooked the jumper cables. The car remains running with battery unhooked and jumper cables off so assuming the alternator is healthy enough. Hooked up a generic OBD2 scanner to grab any codes due to CEL being on, 1 code that said something about cruise control, thought it was saved but it wasn't sadly, I cleared the code. The info center said there was a DSC SYSTEM FAULT then I never seen it again. No other light on dash other than the red indicator because at the time the drivers door was open. I hooked up the battery while car was still running. Gauges seemed normal and not acting weird. Checking lights, left turn signal worked but not the right, blinking fast I assumed a bulb was out, that's fine. All seemed good so I drove to the gas station and filled the tires because they were low and I now find that the instrument cluster was having a dance off, temp, speedometer, and fuel guages were bouncing like crazy but not the rpm, assumed it was because the battery had a bad cell so no biggie already planned on getting a new battery. At this point the car hasn't been shut off yet. Went and did title transfer, this was the first time the car got turned off. Went to try and start the car back up and it only cranked but wouldn't run. Redid how I started it prior, still cranking not running and not getting a PATS 16 code with no other check engine light or codes. So I got a ride to the parts store and got a new battery. Hooked that up and same result, cranking away not running and PATS 16. Ended up having it towed home.

Had left the battery unhooked overnight in hope of resetting systems. 12 hours later I hooked the battery up got in and tried starting the car. Turning the key slowly through 1&2 and I noticed the lock cylinder was pretty worn but systems come on, I hear the power relay in passenger kick panel click, fuel pump primes, and security light came on solid for few seconds and turned off, gave it a try to start, nothing, but this time security light isn't blinking so I gave it another shot, same thing. Fuel guage was still freaking out and temp guage would creep up to 1/4 mark and drop repeatedly but speedometer was still and so was rpm. Third time was the charm and engine came to life. I let it idle and it felt smooth. While running I peak under hood to inspect and listen and discover there's a coolant leak passenger side of upper intake manifold, would explain why the temp guage be at operating temp within 5 or so minutes. Ran the OBD2 scanner with no results and peeked at a couple sensors it could read and nothing showed abnormal. So I shut her down and entertained a restart and back to cranking and not starting this time PATS code 23. Tried unhooking battery, touching cables together and hooking battery back up, still crank no start with PATS code 16.

Figured I'd look into the ignition cylinder and switch. Unhooked the battery and pulled the ignition assembly. Did some disassembly and cleaning and inspection. The tumbler is pretty worn itself but it still makess the switch cycle through this time with more confident clicks with key cycles. About 10 hours later I returned to the car and installed ignition assembly and hooked the battery up, 1st attempt was only cranking no PATS, 2nd attempt for a crank and a sputter still not PATS, 3rd time started up and idles great. No misses. No codes or warnings. Shut it off and turned key on without trying to start and PATS code 16. Waited a day same stuff but, left turn signal no longer blinks nor making sound, left blinks and works but no sound. Noticed the telescoping doesn't activate when the keys in.

Leaving the car battery unhooked for a while nets me this over and over. So time to dig. Fuses all are good, relays have been swapped around and haven't found any exposed wires yet or anything unplugged. The gauges don't freak out anymore.

I'm hoping for some help or ideas. I have browsed around for a while and haven't seen anything yet that may help my situation and appreciate anyone's help.

 

This last start attempt I just tried, after the third start attempt it sputtered to life and I had to tap the accelerator a few times to keep the car from dying but after some misfires(no code thrown but could feel the misfires) idled fine no codes. Still does PATS 16 if I shut her down and go to try to restart.

 

I forgot to mention that each time I reconnected the battery the doors are closed and no key in the ignition the radio comes on playing

 

PATS codes are various places on JagRepair.com - Jaguar Repair Information Resource

such as
http://www.jagrepair.com/images/Trai...l 02-20-02.pdf

 

I had a similar non-starting issue with my 2002 3.0 litre S recently, with accompanying PATS 16 code. I also changed the battery and checked all fuses and relays. Eventually discovered no fuel pressure on the rail under the hood although the fuel pump was running. Checking circuit diagrams endlessly I worked out relays for fuel injectors and coils are fed through a small diode in the center of the engine bay fuse box. This had failed and was showing high resistance in both directions. I jumped the terminals of the diode ( just a short lead with 2 small spade terminals on the ends), It fired right up, so I ordered a new diode from the Jag dealer for less than $10. It's not a common failure but worth checking . Don't run for long without the diode, since it obviously has some protective purpose.

Tim

 

Welcome to the forum. That's some stellar troubleshooting.

I'm still puzzled how that turned into a PATS code 16, but who knows. Glad to hear you got it sorted out.

 

Ooh, don't do that anymore. I started twitching uncontrollably when I read this bit.

One function of the battery is to act as a giant capacitor to dampen the normal voltage spikes created by the alternator. Without a battery, who knows what sort of spikes were present, with massive potential to damage sensitive electronics.

Sorry I have nothing to add about fixing the root cause behind code 16. Hopefully you did not cause any further damage running without a battery. But definitely don't tempt fate by trying that again.

 

+1 especially on modern (er, post 1990?) cars, they rely on the smoothing a battery generally enforces.

 

Gave that a shot with a jumper and made no difference I believe. Ended up throwing pats code after 3rd start attempt. I ended up disconnecting battery and trying again but with the doide back in place. 3rd start attempt engine stumbled to life required a few light throttle presses to keep it alive, some misfires and grumbling but ended up getting it to idle with only feeling slight misses or "sputtering". Rpms would fluctuate a couple hundred rpms. No codes while running but fuel trims seemed high. Shut it off and this time going to try to start again and PATS wasn't flashing until after 2nd restart attempt. Both restart attempts were only cranking no start no sputtering

Can a failed start cause pats to pop up and if so what sensors are usually the culprit. Being that it's temps hovering around -4 outside time spent outside with car is short.

 

It could be an air leak.

It needs a few sensors to be working else it cannot fuel correctly and that can cause what you have.

 

Please keep in mind most of us have not had to deal with PATS faults, so we may not be able to offer much in the way of assistance. A few things you can do:

PATS is a Ford system of that era. Instead of searching just for Jaguar PATS codes, try a general search across the web for Ford, Lincoln, etc. You may find a lot more relevant results by casting a wider net. You may have to extrapolate some of the answers, but it should point you in the right direction.

Some of the quick searching I did for code 16 showed most resolutions were for power problems to the PCM. It's easy to panic and think it's caused by some exotic computer problem. In reality, the fix was often a loose fuse or failed relay.

It's also quite odd that you are not consistently getting PATS faults with each start attempt. Intermittent faults can be hard to track down, if concentrating on the PATS codes which seem to come and go. But you do have a more consistent fault that is hopefully easier to pin down: The no-start. So what I'm suggesting, instead of chasing a PATS code that may not be present at any given moment, run some basic diagnostics for the no-start condition. Primarily, check for spark and fuel pressure. For example, even if you hear the pump running, still check for fuel pressure at the injector rail. See what a scanner says for fuel pressure, and then compare to a mechanical gauge at the test port. With any luck, if you can find the fault preventing the engine from starting, it may also take care of the PATS codes.

Be sure to keep the battery charged. Don't let it run down during repeated start attempts. On a similar vein, don't abuse the poor starter in hopes the engine will start. An engine in good working order should fire up within one or two revolutions of the crankshaft. If not, figure out why and correct it, versus cranking and praying. Your battery and starter will thank you.

Wiring diagrams are here, near the top of the page:

JagRepair.com - Jaguar Repair Information Resource

See figure 01.6 for Powertrain Control Relay #1, which feeds battery power to the PCM. You had mentioned swapping relays around, but be careful with the numbering. Although called Powertrain Control Relay #1, the confusing location is actually #14 in the front power distribution box under the hood. There's a diagram of the relay numbering near the front of the wiring diagrams.

Do you remember which relay was originally installed in that location? If so, carefully inspect the prongs for discoloration. If the relay gets hot, the sockets (in the panel) can loose their grip and cause a poor connection. Individually test the grip of each socket with a strip of metal the same dimensions as an individual prong. Even if the relay seems to plug in firmly, one of the 5 sockets could still be loose, so be sure to test them individually.

 

I moved the relays back to where they originally were. Looked at prongs and seen no hot signs or corrosion. I will be ignoring the whole PATS light stuff since I can manipulate the car into starting. Fuel pressure from the sensor is reading right at 39psi once I get passed the whole keeping it running part and it's idling on the smooth side. I did observe the fuel trims were looking high. Still won't want to restart

 

Not likely the problem but have you checked the timing chain guides/tensioners/etc are OK? You want the Gen 3 ones.

If any vital sensor (IAT, ECT, ...) is misreading you can expect starting problems so check they are not reporting plausible but wrong values.

An air leak that comes & goes can be a pain, too. Check all vacuum hoses, joints, etc. Be aware that a leak you cannot hear is still a serious issue to the car.

 

This is good, but doesn't tell the whole story. The computer will regulate the pump output to 40 PSI based on feedback from the pressure sensor at the injector rail. However, if the sensor is inaccurate, the computer will happily regulate pressure to the wrong value. That's why it's important to verify the actual pressure with a mechanical gauge. On my '02 V6, there's a test fitting near the oil filler cap. I think the early V8 also has the same fitting (it looks like a tire valve stem) but I'm not sure where it is located.


Once started, how reliably does the engine run? Some OBD fault codes are not set until 2 or more drive cycles are completed. Just wondering if you feel confident enough to go for a drive, as long as you are careful not to turn off the engine until you get home. If you can complete a couple of drive cycles, some fault codes may be logged that would help with troubleshooting. Just thinking out loud, so don't get yourself stranded somewhere.

 

Some monitors may set if you just idle long enough for it to warm up properly, switch off & let it cool fully (make sure fully), and then re-warm it up. (A really crude 2 "trips".)

Some codes may flag then.

Before then, some may pop up as pending codes (you should always have P1000 or P1111 - here you'd expect P1000 showing not all monitors have set).

 

Sorry it's been a moment since I've replied any. So I had gotten the battery fully charged and cleaned maf and checked for any obvious vaccine leaks. Have yet to get the car to restart. The last time I had convinced it to start, it struggled to stay running and wanted to stall out so I hAd to give the gas pedal some slow taps to keep the car running. About 30 secs of convincing it to stay running and it will idle on its own. I can feel something like a slight misfire, very slight, and the rpms will bounce between 600-800rpms. No warning lights, no codes, heard no immediate vacuum hissing or any abnormal sounds in the engine bay. Tapping the gas pedal and engine seemed hesitant. Fuel trims seemed all over the place while idling. When I shut the car off and go to key position 2 without trying to start it the pats light yells at me and restart attempts won't get engine to run again.

Today when having the obd2 plugged in it shows me stft on both banks being at 99% and will slowly drop down to mid 60%s.
Fuel pressure sensor says I'm at 39psi. This is before a start attempt. Then I noticed while sitting there for A moment with the key in position 2, I have 2 gauge needles giving me attitude, fuel needle was bouncing around and the temp gauge claiming to be at the 1/4 mark when the sensor read 41f on the OBD2 which seemed truer because that's about what the weather was today. Turning the key off and out the temp gauge moves to the halfway mark and stays there while the fuel gauge is back at its resting position.

 

Again and again what are the PATS codes?
Hard to fix if your running blind!
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This value doesn't sound right. Before starting the engine, you should have approximately 55 PSI. Once started, you should see around 40.

Check out this thread for a verbose explanation of the confusing method used to regulate fuel pressure:


https://www.jaguarforums.com/forum/s...estion-261975/


One possibility is a failed fuel pressure regulator, leaking raw fuel directly into the intake manifold. Disconnect the vacuum line between the regulator (on the injector rail?) and the intake manifold. Swab the inside of the line with Q-tip. It should be dry as a bone. If not, the regulator is bad.

No idea what is happening with the PATS trouble. Seems like you may have more than one active fault.

 

I get code 16. Very randomly will code 23 come up and that's after several restart attempts