Parts or components should not be replaced with reference to only a B1236 Skoda DTC. The vehicle service manual should be consulted for more information on possible causes of the fault, along with required testing.
The problem is caused by the variable cylinder management system switching on and off during light throttle conditions, at cruising speeds, or when driving on flat roads. The constant switching causes excessive oil consumption and the trouble codes appear when oil pressure drops to the point where it can no longer operate the VCM system.
Air Conditioning Pressure Sensor (ACP) Insufficient Pressure Change Each time the A/C clutch engages, the PCM is looking for a pressure change in the refrigerant. If the change in pressure is outside of the calibration the DTC will set. A/C system mechanical failure Open ACP or VREF circuit A/C sensor damaged A/C system electrical failure A/C clutch always engaged Verify A/C system function, including refrigerant charge.
B1236 meaning and repair processes are the same for all Skoda models.
B1236 Skoda Trouble Repair Process:
The B1236 Skoda check engine lamp is perhaps the most troubling of lights because it could mean so many different things, from you didn't screw the gas cap on tightly enough to look out for pistons flying through the hood and into the stratosphere. The easiest way to find out what this light is telling you is to hook your vehicle up to a scan tool. OBD 2 diagnostic tool looks a little like an oversized calculator and plugs into a communication port inside the car. After you instruct it to perform the scan, it speaks with your car's computers to find out exactly what's prompting the light to turn on.
b1236 is a very common fault code for the thermostat. If you have this fault it will need to be replaced. I would start with that repair, clear the faults and perform a 30 minute battery reset(disconnect the negative cable off of the battery) and retest the vehicle.