2004 Boxster S Check Engine Light and fault code help

AndyW1973 · Apr 22, 2017

After 4 years of trouble free Boxster ownership I have had a check engine light come on this evening after about 5 miles of driving. The Torque OBDII reader gives code P2096 - Post Catalyst Fuel Trim System Too Lean Bank 1 as the fault. Is this likely to be an O2 sensor issue or a more sinister problem such as a failing CAT? I intend to clear the code tomorrow and go for another drive to see if the code reappears and I will also check for any obvious exhaust leaks. Is this a fairly common issue in the Boxster community?

I guess if it comes back I'm heading for my local OPC to get a more accurate diagnosis [

] To top it off, this has happened while the BMW has been sat on the lift at my local garage for 3 days while they try and source a replacement brake caliper carrier that was damaged during a routine disc and pad change! Talk about kicking a man while he's down!

Things can only get better.....

Motorhead · Apr 22, 2017

Sorry to hear about your multiple problems Andy.

In the first instance I think that you're on the right track regarding the Lambda sensor (clean or replace) and possible exhaust leaks. After that you're probably in the hands of your local Porsche Centre or a decent Indie.

Hope you get it sorted quickly.

Jeff

Richard_Hamilton · Apr 22, 2017

Unlikely to be the cat - much more likely to be the sensor. As a check:

Read out regulator delay after TWC, bank 1, using PST 2, PIWIS, or a scan tool
Less than 1.2 seconds - oxygen sensor OK
More than 1.2 Seconds - Replace oxygen sensor

However, MY2003 and early 2004 986 Boxster S's had an anomaly in the fuel map (see attachment). The introduction dates of the new fuel maps were:
10 February 2004, as of the Vehicle Ident. No.: 98 Z4S 64 0783
12 February 2004, as of the Vehicle Ident. No.: 98 Z4U 64 1777

If your car precedes this, and the regulator delay is OK, you might want to get the DME map updated. Any decent indy will be able to do it.

jmaddox · Apr 22, 2017

Don't forget after clearing code it's on the third cold cycle it will come on again - not immediately.

AndyW1973 · Apr 22, 2017

Thanks for the replies, this is very useful information. I cleared the code this morning and went for a 30 odd mile run - it didn't come back on - but it sounds like it needs a couple more cold cycles to be sure? Anyhow, driving with the roof down has highlighted another issue - a tappety rattle that comes in at about 2800-3000rpm. It is most noticeable on light throttle and doesn't seem to be audible above and below these rpms. Today I removed the serpentine belt to check for play and noise from the various pulleys.... low and behold, the water pump is knackered! Lots of side to side wobble and noisy on spinning.... and I said things could only get better! Ha!

I've just checked my certificate of authenticity and my production completion date was 13.01.04 and my vehicle ident no. is earlier than 0783 - I guess mine needs updating!

I'll be booking it in at my local specialist indy for a new pump and I'll get them to have a look at the sensor/DME issue while I'm there.