General Information

General Information:

As electronically controlled systems continue to be developed and introduced in BMW vehicles, the level of complexity and sophistication of these systems has risen dramatically in the past ten years. This does not mean, however, that the diagnosis and repair of these systems is more difficult. On the contrary, these systems are possibly easier to diagnose, if a systematic troubleshooting method is used.

The purpose of all electrical troubleshooting is to identify and correct a malfunction which has caused a customer to complain. However, before repairs are attempted, the following steps should be taken:

1. Verify The Problem
Operate the problem circuit to check the accuracy of the complaint. Note the symptoms of the inoperative circuit.

2. Analyze The Problem
Refer to the schematic diagrams in DIAGRAMS / ELECTRICAL. Determine how the circuit is supposed to work by tracing the current path(s) from the power source through the circuit components to ground. Based on the symptoms noted in step 1 and an understanding of the circuit operation, identify one or more possible causes of the problem.

3. Isolate The Problem
Make circuit tests to prove or disprove the preliminary diagnosis made in step 2. A logical, simple procedure is the key to efficient troubleshooting. Test for the most likely cause of failure first. Try to make tests at points that are easily accessible.

4. Repair The Problem
Once the specific problem is identified, make the repair using the proper tools and safe procedures.

5. Check The Problem
Operate the circuit to check for satisfactory circuit operation. Good repair practice calls for rechecking all circuits that have been worked on.