hello, ive taken my 2003 s-type to autozone and got a read out of p01071 and p01074 (off top of head). I sprayed the MAF sensor with cleaner but the car still gives the "restricted performance" indication and the car really putt putt when accelerating. IS THERE A WAY TO KNOW FOR SURE THAT THE MAF SENSOR IS NOT WORKING, A TOOL, FOR INSTANCE THAT COULD CHECK BEFORE I BUY A NEW ONE? IF NOT, WHERE, ONLINE, WOULD BE THE BEST PLACE ECONOMICALLY TO BUY ANOTHER SENSOR? Thank you.

 

p.s. the codes are P0171 and P0174 for the 2003 Jaguar s-type, 6 cyclinder, 3.0. Thanks again.

 

Welcome to the forum DJ,

I've moved your question from Jaguar Forums Advice / Feedback & Suggestion Center to S-Type forum. The Advice / Feedback & Suggestion Center is for posts about the forum and not for technical questions. Members here with the same model will be able to help.

I've also put your Intro in a new thread of your own. Here's a direct link to it:

https://www.jaguarforums.com/forum/n...jw0104-121191/

You'll find some useful advice there about posting to the forum.

Graham

 

Those are not MAF codes so leave it alone (careful cleaning does no harm).

They are lean codes - see codes PDF in stickies or JTIS, both are free downloads.

Many others have them so use Search and follow the usual advice. You'll struggle unless you can read fuel trims. A cheap OBD tool like elm327 will do that.

You may have an air leak or bad coils or other things so OBD is a good place to get data.

 

+1 for not randomly replacing bits until the problem goes away...

What are your symptoms?? Restricted performance all the time or does it come on after some driving then go away??? Have you checked all the vacuum hoses and connections? Checked for a cracked air filter box?

Get a good OBDII reader and test under mobile conditions. I used an ELM327 and a laptop with Proscan 5.9. Plot each sensor bank and watch for the failures.

If it does end up being the MAF, I replaced mine with one from Toyota (the identical part is used in many Toyotas and Lexus) for about half the price.

Happy hunting

 

Sounds like a vacuum leak, (why people always jump at MAF sensors as a cure-all i don't understand)


There is probably a cracked hose or loose clamp somewhere... look around for vacuum leaks...

 

identical symtoms. p0171 and p0174, random restricted performance, for a few minutes then goes away, check engine stays on.

However, I did not notice any performance degradation... But this was my solution.

visual inspection for cracke/loose hoses, everything looked fine

#1 tightened gas cap
#2 changed air filter (old one was warped!)
#3 properly closed air filter box (the two clips on the ends are no fun so instead of locking them in, the last guy just butted the box up to them.)
#4 cleaned MAF
#5 properly seated and tightened hose clamp behind MAF.

I did everything in one shot and cleared the codes so no way to pinpoint but I
hope that helps

by the way I've driven 300+ miles since then code free...

 

#5 would be the only possible one on your list that could fix those codes if the clamp was way loose.

 

I could've save a lot of time and trouble by jumping straight to the MAF...
(See post #59) https://www.jaguarforums.com/forum/s...4-52450/page3/

 

Except it's not usually that on an S-Type unless you have MAF-specific codes. Lean codes are not MAF-specific codes.

 

I hear ya, John. I'm not advocating a "throw parts at it" approach. Just pointing out there ARE cases where the codes are lying to you. I had a tremendous advantage in having a near-as-makes-no-difference identical car and once I obtained the ELM327BT and TorquePro to record data from it, it was easily sorted. The "faulty" MAF was reporting higher airflow than the good one and by all rights should've led to "rich" codes rather than lean ones. I chalked it up to a tolerance stack-up issue, as it took nearly a year to manifest the same issue once I transferred from the 05 to the 03.


YES! Given these two codes you should do an exhaustive inspection of all your vacuum lines (Particularly if you have a Pre MY03 - likely that line UNDER the intake manifold) and yes, you should have the means to record live data (more than fuel trims only, though they are primary in confirming a vac leak) if you want to ferret out what's really going on. I'm just saying, in retrospect - if I'd jumped straight to the MAF and replaced it...I'd have saved several days' worth of troubleshooting and poring over vacuum lines (and would know far less about how the engine is controlled) but as to results.....would've arrived at the end state much sooner....but next time I get P0171/174 I'll hook up the scanner and go for a short drive, then retire to my laptop and Excel for analysis.....

 

Hmm somewhere in the "How To" section I believe a fellow member took the time to answer or start to answer the "infamous vacuum leak" on the "granny" 3.0 litre, trouble codes with color coded pictures and explanations, that IB is profiting off of.

 

Rick, your vacuum leak post, if it was paper, would probably be rivaling Brutal's headlight fix for most well-worn on the forum! Who's IB?
(Forgive me for not thinking to link it)