Oscilloscope Patterns and Waveforms

IGNITION COIL AND IGNITION POWER TRANSISTOR
Ignition power transistor control signal

Measurement Method
1. Disconnect the ignition coil connector, and connect the special tool (test harness: MB991348) in between. (All terminals should be connected.)




2. Connect the analyzer special patterns pickup to ignition coil connector terminal 3.

Alternate method (Test harness not available)


1. Connect the analyzer special patterns pickup to ECM terminal 10 (No.1 - No.4), terminal 23 (No.2 - No.3) respectively.


1. Connect the analyzer special patterns pickup to PCM terminal 11 (No.1 - No.4), terminal 12 (No.2 - No.3) respectively.

Standard Wave Pattern:

Wave Pattern Observation Points:

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 too low, approximately 2 V.

- 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.