Antipollution error possible reason (MAP sensor)

[JeffT]

My 2002 1.6 16v has been getting the Antipollution error widely discussed on this forum. I changed the spark plugs and coil pack but still got the error which disappears if I turn off the engine for a minute. This has been happening for around 7 months.
I thought back to when this first started and realised it was about the time I replaced the original radio with an aftermarket one. I removed the new radio and replaced the original one and for the last 4 days no error. It is early days but it seems the ECU doesn't like the original radio missing.

[GrandadMonkey]

Sounds as if you've found the problem. A dirty or clogged air filter could make it run too rich though. Is that clean?

[JeffT]

I did a complete service last year, 2500 miles ago, so the air filter is pretty clean.

[GrandadMonkey]

So it's looking like the radio then.... odd that!

[gazza82]

2002 model might be multiplex system so radio could be the problem. Did you just unplug one and plug in new one?? Wonder if BSI needs to be told??

I had to update the BSI on a standard Clarion radio to get the rear speakers to work on our mutiplex hatchback .. oh and to receive AM radio stations!

[JeffT]

I just plugged in the new radio using an adaptor cable.
It would be interesting to know whether others with the same problem have the original radio or a replacement aftermarket one.

[JeffT]

It is now 3 weeks since I refitted the original factory radio and there has not been an Antipollution error since. Previously it was every day.

[JeffT]

Well the Anti-pollution error is back. Taken up reading advice again on the possible reasons and it seems that no matter what anyone does it can't be cured.

[Capncol]

Have you got diagnostic codes? There are numerous causes of anti pollution fault and the codes would narrow it down.

[JULIE1806]

Hi Jeff
as you might have seen from similar posts, my 52 pug has been suffering from the same problem with
anti pollution fault periodically appearing and rendering the engine in go slow mode. I just pull over for a couple of minutes, rev her up and get 2/3 weeks before the next time....haven't got round to checking the codes yet as it's my son who's the mechanic and he's away for a while but ever since I've been maxing the revs at start up (maybe blasting clean the filter) I seem to get more time between AP Faults....unlike prior to the new throttle body/sensors being replaced and re-learnt when the fault appeared every couple of days

[Capncol]

Julie. "Maxing the revs at start up" is not good for the engine. The oil won't have got round properly, and you may be doing damage to cam bearings as a result (ask your son). You won't be blasting the airfilter clean, but you may be dislodging buildup from around the lambda sensors.
Do you do mainly short journeys in traffic?

[JULIE1806]

Yes, just to and from work which is a 5/6 mile round trip. My son did say I ought to do some longish trips on the motorway but am a little weary of doing any long trips....would this help??

[Capncol]

I suspect the lambda (o2) sensors my be getting coated with a buildup as they are sited in the exhaust.
On short slow runs, the exhaust system and catalytic convertor don't get to full temperature for long enough to burn off the contaminants.
Using budget supermarket fuel doesn't help in those driving conditions (if this is what you use)

If this is the case. an occasional long, motorway run will help, as will driving it hard occasionally (traffic permitting) aka Italian tune.

This would be my guess, but the real answer is to get the codes read, and be guided by them. Post them here if you want help with them. As I said, without the codes, we would just be guessing.

[JeffT]

Have you got diagnostic codes? There are numerous causes of anti pollution fault and the codes would narrow it down.

Hi
Error codes P0341 and P1336 which seem to be related to cam position sensor errors.

[Capncol]

Take out the crank position sensor and try giving it a clean as they often get metal swarf from clutch assembly stuck to the end of it. If you have a digital meter, check it's not open circuit.