Non-clearing EML

The engine management light keeps coming on in my 2012 Vauxhall Corsa 1.2 ECOFLEX stopstart with 103,500 miles and engine code A12XER. The code it shows is ‘P00B4 generic (D.T.C definition not found refer to vehicle service manual)’. Even though I cancel the code with my Autel Maxiscan MS-509 and put out the light, it comes back on in a short time.

Tim O Meara

On your Corsa, the code ‘P00B4’ refers to the coolant temperature and indicates that the circuit is returning a high voltage. This may be due to a short in the wiring or the sensor. It should be possible to read off the live data using your Maxiscan. By doing this you should be able to tell if the coolant temperature sensor is indicating a correct or unnaturally high or low temperature.

The code can also be set if the IAT (intake air temperature) is below -7°C, which is possible if the IAT sensor is faulty. Again, checking the live data should be able to identify if this is the problem you are experiencing.