BMW Diagnostics and Procedures FAQ: Check Engine Light
If the BMW Check Engine Light (CEL) is, or has been, on there will be stored codes pointing to what is wrong. It is critically important that these codes be read with the proper diagnostic system. That means a dealer or very well equipped BMW indie shop. The entire car needs to be scanned, especially on later cars as there are a lot of electronics and they interact. Examples of proper diagnostic systems would include: BMW's DIS/TIS ("GT-1")... ('07 and older) BMW's newer systems, known by various names: ISIS, ISTA and ICOM BMW's INPA Autologic SnapOn systems with the proper BMW S/W Matco Launch with the proper BMW S/W Understand that the fault codes are not necessarily to be taken literally. In many cases a particular fault code just tells you what the car is unhappy about, not necessarily what the real cause is. And that is where the experience and skills of a pro are important in interpreting what the codes could mean. While P codes below 1000 are...