Polo 9N problems

[mc]

Hi, just got myself VAG-COM, very pleased with it! Hope you can throw some light on these codes please.

I checked why the engine light was on my sisters polo 9N.

16804 - Catalyst System; Bank 1: Efficiency Below Threshold
P0420 - 35-00 - -
16502 - Engine Coolant Temp. Sensor (G62): Signal too High
P0118 - 35-10 - - - Intermittent

I'm going to change the Temp sensor, but will I need to log to check the lambda sensor, or could the coolant sensor be causing the efficiency problem?

Also I got codes 01271 and 01596 a few times, but the aircon/heater all seem to work fine?


Thanks for your help!
Mike

 

[longman]

I would change the Temp Sensor, clear the faults and then see if the Lambda one comes back.

You might be lucky but I do think the 16804 code is saying there is a Lambda problem.

Not sure if it works on Polos but Block 34, column 4 will show you an OK / Not OK Lambda test for range and aging.

 

[DPJ]

I would change the Temp Sensor, clear the faults and then see if the Lambda one comes back.

.....

Yes, I agree.

 

[mc]

Thanks guys, I'll give that a go.

 

[mc]

Sorry to drag up an old post!!

last time changing the coolant temp sensor fixed the problem cheap fix!

The CEL has just come on again on the polo but this time its just the code for the lambda sensor thats stored (same as before)

does this code refer to the sensor on the exhaust manifold or the one after the cat? I didnt realise there were two until i came to order a spare and got asked by the parts man...

car seems to be running fine so seems to be just intermittent problem.

cheers

Mike

 

[RUM4MO]

Well, its not actually a lambda probe error code that you have listed - its just a "cat efficiency" problem, so you have not actually been getting any O2 Sensor Bank 1 S1 or S2 codes then you would just be guessing which one is causing the problem. Have you check the VAG-COM site for clues - ie the VAG-COM Wiki area? (S1 is the manucat one and S2 is the down stream one.

 

[BeartheBruce]

While you may be looking at a sensor problem, more likely you are looking at a vacuum or exhaust leak causing this problem. Could be a secondary air injection problem also. As was suggested, the Ross-Tech Wiki gives a lot of suggestions as to areas of fault. Leaks are the most likely.

http://wiki.ross-tech.com/index.php/16804/P0420/001056