Have EDC 16 hardware in an 05 KJ Jeep Cherokee CRD.( Liberty for US readers). There is a barometric pressure sensor in the ECU which compares its reading with an air pressure sensor downstream of the air cleaner. The circuits purpose is to set the check engine light if there is an appreciable difference in readings. This would normally occur if the air cleaner was restricted. The fault light sets only if the engine rpm drop to around 800 rpm (a bit above normal idle). If I could reset the rpm parameter to a speed the engine does not drop to, eg 500 rpm, the light would not set during normal driving. Would possibly still come on at start up, but once cleared, would not return until the next start up. Have checked out the circuit as best I can and have assumed the fault is with the sensor in the computer. The air pressure sensor was replaced by a new one and a used one, and the problem remained. The sensor output changes as expected with pressure changes applied to the sensor.
Any ideas as to what hardware and software I need to buy to reset the parameters?
John