hi, got a p0171 fault code on my str 2002, system too lean bank one, long term fuel trim 153% bank one and two, short term fuel trim 128 bank 1, 127 bank 2, any ideas please

 

Those figures look odd but use Search for what advice others have been given then follow it.

 

Here's a good primer on interpreting fuel trims:

JagRepair.com - Jaguar Repair Information Resource

 

Hi andy,

Here are the definition and possible causes of P0171:




Even though you only have a Diagnostic Trouble Code for Bank 1, both of your banks are running lean, so the most likely cause is an air leak in the intake plumbing somewhere between the MAF sensor and intake manifolds, or a vacuum leak. If you can't find a crack in a plastic or rubber hose or a loose connection, a smoke test may help.

Are any other DTCs triggered that might provide additional clues?

Cheers,

Don

 

thanks for the tips, i had a p0146 fault a few weaks ago,jag specialist diagnosed upstream 02 sensor bank one, i replaced all 4 and has run great till now,taking it in on thusday for a vacuum test ect, thanks again.

 

thanks again, just had a check at my local garage, cofirmed p0171 but not getting any live data, sais o2 sensors turned off,hmechanic seems to think its been remapped in the past or some king of box fitted, wher is the ecu on these please

 

That is incredibly unlikely. Much more likely is they don't have much of a clue. I'd run somewhere else (or DIY)!

 

thought I did, where is the ecu located on a 2002 str please.

 

You really don't want to suspect it without the most compelling of reasons. Take a look at the number who've had problems out of the hundreds of thousands of posts.

Hint: nearly none - and they didn't have a code such as P0171 (which is a common code for good reason).

BTW refer to the freely downloadable workshop manual

 

ok thanks, wanted to check if any remap company stickers on it,

 

still cant uderstand why 2 obd tools wont read live data.

 

Fuse/wiring/other fault or cheap/bad tool(s)/software. All fairly common.

You'd have to try VERY hard to find anyone who can remap your car as you inevitably have the oddball Denso PCM.

 

I doubt very much that it's been mapped.

 

I had the same code recently after my Jag sat in the garage for a month. Since there was NOTHING wrong before, I drove it for a 20 miles, came back, disconnected the battery, and reset the system when I reconnected it. Fixed. For 4 years, some of our experts have written about how these cars go nuts with low voltage. It is cheap to measure your battery voltage to be sure.

 

Hi David, I have a very similar situation. Been fixing up my 2004 3.0 S-Type so been off the road for a couple of months. When I went to turn back on the battery was flat. I've charged it for ~8 hours and car starts no problem now but I'm getting P0171 and P0174. There was nothing wrong before I took it off the road and all repairs have been suspension, brakes, EPB etc so nothing in engine bay. I disconnected the battery again for an hour (and touched the live and ground, reconnected and let it idle etc but code came back after a restart and 20 mins or so. Is there something in your 'reset' that I am missing?

Thanks, G

 

From what you say you may have genuine faults. Follow the usual advice about fuel trims.