Ignition Control Module: Testing and Inspection

IGNITION COIL AND IGNITION POWER TRANSISTOR
- Ignition coil primary signal
Refer to Ignition System
- Ignition power transistor control signal




Measurement Method
1. Disconnect the distributor (ignition power transistor) connector, and connect the special tool (test harness: MB991348) in between. (All terminals should be connected.)
2. Connect the analyzer special patterns pickup to distributor connector terminal 3.

Alternate method (Test harness not available)
1. Connect the analyzer special patterns pickup to PCM terminal 11.

Standard Wave Pattern:

Wave Pattern Observation Points




Point: Condition of wave pattern build-up section and maximum voltage (Refer to abnormal wave pattern examples 1 and 2.)

Examples of Abnormal Wave Patterns




- Example 1
Wave pattern during engine cranking

CAUSE OF PROBLEM
Open-circuit in ignition primary circuit

WAVE PATTERN CHARACTERISTICS
Top-right part of the build-up section cannot be seen, and voltage value is approximately 2 V too low.




- Example 2
Wave pattern during engine cranking

CAUSE OF PROBLEM
Malfunction in ignition power transistor

WAVE PATTERN CHARACTERISTICS
Power voltage results when the ignition power transistor is ON.