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View Full Version : Skoda Fabia 1.6 2012 Tdi Cr 75, DPF and EML light on, VCDS error code 9854-P246F CONFUSED



ABDUL999
20-10-2015, 01:29 PM
New to forum hope this is the correct place for this, basically had engine management light on for about 2/3 months from when i bought the car, and then the DPF light came on, so bought VCDS to check this and found error code P246F which is the sensor 4 on Bank 1, i believe this is the sensor with orange coloured connector just after the DPF?
http://i247.photobucket.com/albums/gg152/111abdul111/Mobile%20Uploads/7E0BED5D-7FC0-4DB3-8B90-CE9081FD17A2.jpg
checked the values on advanced measurement (using VCDS) and sensor 4 is giving reading around 999.987 celsius which is clearly where the problem lies, and this is preventing a full regen of the DPF.

im not sure which sensor is number 4, and to confirm the problem i disconnected the orange connector from the car and i was expecting the temperature signal to disappear? but it kept giving the same value around 999.987 celsius, did an engine scan etc again and it is still giving only the original error, there is no mention of the sensor being missing?

also to check if there may be something wrong with the connector i removed the plug on sensors near the turbo and before the DPF, but once again the reading of temperature staid around 20 celsius when car is off, and this increases when car is running.

A bit baffled as to why I'm still getting reading when i disconnect all the sensors plug. could this be a bigger problem than what is showing on the VCDS, about sensor 4 bank1?

http://i247.photobucket.com/albums/gg152/111abdul111/Mobile%20Uploads/D088E562-8129-4D2D-8B09-AAD2AD244555.jpg

Flash2
25-10-2015, 06:33 PM
The fault you may have is an open circuit sensor. With the sensor being open the engine PCM can't see that the sensor is disconnected because disconnecting it creates an open circuit which is what's already there...follow?

What temperature do you get in the measured value when the engine is cold and not running? Still the same reading? To test the wiring between the sensor and the PCM, simply bridge the two terminals on the harness connector (the connector leading to the PCM) while monitoring the the measured value. With the terminals bridged the temp should drop (assuming it's a PTC type sensor).

Regards.

Jim.

ABDUL999
05-11-2015, 02:15 AM
i doubt it was an open circuit as the readings where staying pretty much constant for other circuits aswell when i disconnected the sensors...... and yes i was getting reading of around 999.99 celsius on a cold and warm engine


anyway got it sorted,disconnected sensor 4 on bank 1 (i.e sensor with orange connector after the dpf unit) used a 470 ohm resistor, and bridged it across the the wires where the orange connector was supposed to go, this instantly changed the live data reading and it was showing between 300 and 400 celsius which was good enough for a regeneration so running the car for 10 minutes cleared everything :)

this confirmed the issue and i bought a new sensor which has just been fitted and working as normal

Flash2
05-11-2015, 10:25 PM
i doubt it was an open circuit
It sounds like it was an open circuit sensor since joining the two wires via the resistor made the temperature reading drop which is what I said would happen. If you had just directly shorted both wires the temperature reading would have dropped further. Admittedly, your method of using a resistor of the correct value is a better test.

Regardless of the method used, you confirmed the wiring between the PCM & sensor connector was OK meaning the sensor itself had to be faulty, so well done for correctly diagnosing the fault rather than just replacing the sensor and hoping for the best.

Jim.

ABDUL999
05-11-2015, 10:31 PM
i only read "open circuit" and assumed you meant that the circuit might have a break some where, my bad.

thanks anyway :)