Hello all,

thanks for the add. I'm owning a 2001 XKR Convertible with 65000 km on the clock in mint conditions since 4 weeks now.

A great car and I enjoy it every day during these summer days in Germany.

But every sunny side has shadows. I get the P0171/P0174 error code sometimes.

Yesterday I tried to find out when the error occurs reproducibly and it is very, very strange.

After 1 hour with all possible driving conditions, fast, slow, high rpm, low rpm, hard acceleration, soft acceleration....... Nothing. No error.

Then a pause
In the end it's a reproducible scenario
[list] [*] when the engine is warm (yesterday there were about 100 km behind me).[*] a short pause of about 5 min with the engine switched off[*] an acceleration to about 120 km/h, no matter if full throttle or very gradual [*] constant driving with cruise control[*] after 3-4 min comes ENGINE POWER LIMITED without any announcement that it jerks, sounds funny, etc.[*] reproducible. Pause-acceleration-constant speed-error[*] The error is reset when the RPM drops below 2000 RPM.[*] After that, the Car behaves normally until the next pause.

Maybe there is someone here who can think of something to do with this where I can best look for the culprit.

Thanks in advance, Robert

 

Sorry for the mistake not to set[/list]in the end of the bullwt points. It makes it hard to read.

But I don't find the Error button

R.

 

If I remember correctly these codes represent a possible air leak. When I had these codes, there was holes in my plastic air intake. A new air intake fixed my issue. Hope this helps you.

 

These codes indicate air leaks, i.e. air not measured by the air flow meter, but detected by the wideband O2 sensor in the exhaust. This can be compensated for to a point (read up on fuel trims). These codes pop up when this compensation runs out of range (25% more fuel!). So either you have actual air leaks (most likely scenario), or your AFM is defective (less likely, but not impossible).

Best is to do a smoke test, i.e. inject low pressure smoke in the intake and see where it escapes. There are too many possibilities to list (o-rings everywhere, etc.) where air can leak. This process is cumulative, all these air leaks add up. You ideally wan to repair, and then monitor your fuel trims and bring them back down to, say, 5% or lower.

If you want to take a look, the Helmholtz resonators on the intake tube are common failure points. Big gaps can develop under torque.

Best of luck, keep us posted.