Mitsubishi Montero (2002-2004). Manual - part 575
INSPECTION PROCEDURE USING AN OSCILLOSCOPE
TSB Revision
MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
13Ab-57
Point B: Height of coil back electromotive force
.
Examples of Abnormal Wave Patterns
Example 1
Cause of problem
• Malfunction of motor. (Motor is not operating.)
Wave pattern characteristics
• Induced electromotive force from the motor turning does
not appear.
Example 2
Cause of problem
• Open circuit in the line between the EGR valve and the
PCM.
Wave pattern characteristics
• Current is not supplied to the motor coil on the open cir-
cuit side. (Voltage does not drop to 0 volt.) Furthermore,
the induced electromotive force wave pattern at the nor-
mal side is slightly different from the normal wave pat-
tern.
IGNITION COIL AND IGNITION POWER
TRANSISTOR
Required Special Tool:
• MB991348: Test Harness Set
.
Measurement Method
1. Disconnect the ignition coil connector, and connect test
harness special tool, MB991348, in between. (All terminals
should be connected.)
2. Connect the oscilloscope probe to ignition coil connector
terminal No. 3.
.
Alternate method (Test harness not available)
Connect the oscilloscope probe to PCM terminals No. 31 (for
number 1
− number 4), terminal No. 35 (for number 2 −
number 5) , terminal No. 44 (for number 3
− number 6)
respectively.
CONTRAST WITH
STANDARD WAVE
PATTERN
PROBABLE CAUSE
Coil reverse electromotive
force does not appear or is
extremely small
Short in the coil
AKX01608 AB
AKX01609
OPEN
CIRCUIT
SIDE
NORMAL
SIDE
AB
AK102984AB
1
2
3
IGNITION COIL
CONNECTOR
OSCILLOSCOPE
MB991348