Hello all,


​​​​​​2003 S-type R, 4.2

I have 16 codes at the moment. Just got the car cheap. Needs some love. I'm a mechanic so I'll do what I need to.

The main hard faults are:
multiple missfires, m
cilyl 1,2,3,4,6,8 (all specifically listed)
Powertrain 1316 (?)

Heated control circuit low (bank 1 sensor 2)

Pending:

Knock sensor 1 circuit low input
Knock sensor 2 circuit low input
Oil temp sensor low
fuel rail ensors circuit performance

And the yet to be determined

P1000
P1646
P1647

I'm thinking they are all relatively related. I of course have restricted performance as well as a handbrake that doesn't function.

Up to the 3k rpm cutoff she pulls well. Doesn't skip or hesitate. The idle is not smooth. Not shackey, just not buttery smooth, I can feel the missfires.

Now, where to start!? 🤣

 

Hmmm, let me kick it off, where are the knock sensors located on the 4.2?

 

Where to start? For the handbrake, are you getting a fault message? If so, start here:

https://www.jaguarforums.com/forum/s...attery-193787/


If you know none of the history of this car, and the battery is of unknown vintage, I'd roll the dice and just get a new battery in there. For whatever reason, these cars are VERY persnickety about prestart voltage. On the 2003+ models, you need to see at least 12.6V before start, or you can expect all sorts of strange problems. One of the primary symptoms is a parking brake fault, so that's where I'd suggest investigating first. With a new battery, you may find many of the other faults quickly clear themselves.

Why do these cars require such a high prestart voltage? Heck if I know, and I work in electronics. I've given up trying to understand exactly why. That's just how it is, and forum experience has showed this over and over again.

If you are not willing to take the advice of some stranger on the internet (can't say I blame you...), at the very minimum please have your existing battery checked on a capacitance type tester. And then put the thing on a charger overnight. This is a very important step, so please don't skip it. If you do replace the battery, please charge that one also, as they typically are not fully charged at the time of sale.

Next step is to check your charging system. Your car has a smart charging system. Right after engine start, it will put out about 14.5V for several minutes, slowly tapering off to around 13.5V.

Moving on, please post the exact 5 digit codes you are seeing on your scanner. Most codes readers and scanners give a misleading generic definition. This has caused a LOT of grief for some forum members. Do NOT use the generic definition for troubleshooting. To help us, please post the complete codes (P0301, for example). You can see the official Jaguar definitions here, your code troubleshooting bible:

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

This document also includes the cylinder numbering protocol on page 3. This may be different than other vehicles, so make sure to follow that guide.

If your check engine light is flashing, do NOT continue driving. The flashing is to get your attention that a medium level problem has turned into a major problem, and your catalytic converters are about to melt down, an expensive proposition.

For the misfire codes, is #7 also present? You did not list that cylinder, which is unusual if all of the remaining cylinders are acting up. Time to get up on my soapbox: If the computer has set a misfire code, please be aware "misfire" wasn't the best terminology that could have been used. Misfire sounds like an ignition problem, at least to me, meaning the fuel and compression were there, but for whatever reason, the required spark was missing or weak. This might lead a good-looking aspiring mechanic to troubleshoot the daylights out of a perfectly good ignition system. I do not care to discuss how I know this.

In OBD-speak, misfire simply means one or more cylinders is putting out low power compared to the others. Pretty much anything affecting the output of a cylinder can set a misfire code. It can be low compression. It can be a valve not opening fully. It could be a clogged fuel injector. And yes, it could be an ignition problem, too, but don't overlook the other possibilities, too. [/soapbox mode off]

With so many cylinders flagged for low power (misfires, if you must...), I wonder if improper fuel pressure is at fault. I'd gamble on a new fuel filter first and see if that helps. You can also pull one or more of the coils and look for oil in the spark plug wells. If the valve cover gasket leaks around the spark plugs, oil collects there and interferes with the ignition. This is a very common problem, and easy enough to check.

If you do find any parts in need of replacement, please oh please oh please do NOT buy any no-name specials on eBay or similar sources. Those no-name parts have caused LOTS of trouble for forum members. Go with OEM quality stuff, not white box bargains.

Well, that should be enough to get you underway. Please keep us posted on what you find, and do let us know the codes you have. Hopefully most of them will clear with a new battery.

 

Thank you very much. I'll start with a new battery. Get it on the trickle charger overnight and go from there.

Once done I'll post back what codes come back and list them specifically. I'm looking at the Jag ids interface but wil use my cheap code reader for now. I'd like to be able to read real time fuel trims etc down the road. First things first: get the car up to "base level" mechanically.

Thanks again, I'll.be back. Btw, 7 wasn't listed. But I'm sure if I drove the car farther than 3 Kms it would have popped up. Check engine isn't flashing but I don't want to drive it in limp mode.

 

Ok, so progress;

Oxygen sensor fault keeps returning.

I didn't mention that my car is fitted with an lpg system. The missfires are worse on log which tells me spark. I'll give it a basic service first.

As a quick in between:

My parking sensors make no sounds. All four sensors are clicking as they should, but no audible sounds at any point. Where would the speaker be?

 

Ok, so progress;

Oxygen sensor fault keeps returning.

I didn't mention that my car is fitted with an lpg system. The missfires are worse on log which tells me spark. I'll give it a basic service first.

As a quick in between:

My parking sensors make no sounds. All four sensors are clicking as they should, but no audible sounds at any point. Where would the speaker be?