Emission Light On and Fault code pulled.

[warptechno]

Hi All - car in question is a 2006 VW POLO 1.2 9n3

Looking to put the wife's polo up for sale but need to get rid of the pesky emission light which has been on for ever.

I recently replaced a gubbed coil pack and reset the fault codes in the hope that this would sort out the problem but it keeps appearing on the dash. I have just lived with the light being on as the car seems to run fine. Have changed pre-cat lambda sensor in the past as was having problems with erratic idling when car was up to temperature (disconnecting the lambda sensor and renewing it sorted it out) but not been having those issues for some time now.

The (generic Torque app) fault codes I had recently were:

P0342 - Powertrain. Camshaft Position Sensor "A" Circuit Low Input (Bank 1 or single sensor)

P0030 - Powertrain. HO2S Heater Control Circuit (Bank 1 Sensor 1)

The car began refusing to start therefore I was forced into trying to tackle this problem once and for all...

I have since replaced plugs, another one of the coil packs (looked on the way out), cam sensor and pre-cat lambda. Car now starts first time, every time and seems to be running a lot smoother and leaner on the fuel.

I am left with the fault code:

Torque App - P0030 - Powertrain. HO2S Heater Control Circuit (Bank 1 Sensor 1)

VAG Com -17524 Oxygen (Lambda) Sensor Heating Bank 1 Sensor 1: Open Circuit


After deleting the fault code the light doesn't come back on again until the car is up to running temp and only when the ignition is switched off then back on again - on comes the emission light...

Anyone have any pointers what to try next (I have been looking through the fuses but they look okay). Don't want to be throwing much more cash at this just to get a damn light to go out.... I'm sceptical at going to a garage with this as no one has been able to get to the bottom of the problem in the past and just seem to want to swap parts out and charge for fault code reading. As mention previously I am looking to sell the car on and obviously need this sorted before attempting to do so. Will mention that the car has just done 70,000 miles.

I have posted on the VW forums but trying my luck over here.

Cheers for any input folks

 

[mty12345]

Hi mate, both those fault codes are for a open circuit, on the heater circuit, for the first lambda. http://wiki.ross-tech.com/wiki/index.php/17524/P1116/004374 That circuit is there to heat the probe and bring it up to temp more quickly after starting the car.

If all the fuses are ok then that means that there is a break in the wire somwhere in that circuit, most likely at the plug, or where the wiring enters the lambda sensor itself. The wiring gets brittle there due to the heat.

 

[warptechno]

Thanks for the reply, someone else mentioned that the wiring that sits at the gearbox going to the lambda plug corrodes so I'll investigate this further.

 

[mty12345]

Thanks for the reply, someone else mentioned that the wiring that sits at the gearbox going to the lambda plug corrodes so I'll investigate this further.

Yeah chances are if you seperate and clean both connectors then that might be all it is.

 

[inbetweener]

I'm guessing you got this fixed but yeh the wiring at the gearbox that holds the multi plugs corrodes


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