Code p1171 returnes every 2 miles!!

[chrjen]

I have an annoying problem, that no one seems to be able to solve.
2001 s80 2,4T 200bhp lpt. Checj engine comes on, and my obd tester says p1171.
The ETM is 3-4 years old, o2 sensor renewed, map sensor is renewed, air intake sensor is renewed, TCV valve is renewed.

The car is not hunting for idle and everything works fine, but the power/performance drops as soon as the check engine is on, not significally but noticeable.

I am running out of ideas, i have a lovely low milage car, which is driving me crazy!

Any input would be much apriciated.

[Dream3r]

Air leak? Sounds like unmetered air, the idle doesn't have to be disturbed. Try a smoke/pressure test.

Try changing the TCV pipes, they'll be over due.

[chrjen]

I have checked them, and they look okay....

[ivor]

Hello
1. An air leak in the intake system. The ECU tries to compensate for a lean mixture.
2. Low fuel pressure

[silverhorse]

Air leak? Sounds like unmetered air, the idle doesn't have to be disturbed. Try a smoke/pressure test.

Try changing the TCV pipes, they'll be over due.
Totally agree. Have had the same problem for a while. Went for smoke test and now I know what is wrong. Wish I had done it ages ago. £90 at my local Volvo dealer. Bit pricey, but they know what they are doing.
Get it on a VIDA diagnostic machine as well and you will maybe get some more specific codes.

[LeeT5]

P1171 - Long term fuel trim, upper limit.

Air leak! and only a small one too. The car would hunt and have raised idle if it were a big leak.

Reduced power when 'Check engine' light comes on because ECU can no longer adapt enough to keep the fuel trim within spec, so it put's the car into 'limp home mode' so you stop driving the car and get it to a garage to be fixed.
If your garage can't fix the problem, take it to another garage that can and DON'T clear the fault before hand. You'll save alot of time and money if the light is on and the cars in limp mode.

[chrjen]

Problem solved.
I found a new friend who had an identical car. We exchanged Maf sensors, and bingo, my car runs superb again.