MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS
TSB Revision
MULTIPORT FUEL INJECTION (MFI) <3.0L>
13B-663
Example 2
•
Cause of problem
Damaged rectifier or vortex generation column.
•
Wave pattern characteristics
Unstable wave pattern with non-uniform frequency. An igni-
tion leak will distort the wave pattern temporarily, even if the
volume air flow sensor is normal.
CAMSHAFT POSITION SENSOR AND
CRANKSHAFT POSITION SENSOR
Required Special Tools:
•
MB991348: Test Harness
•
MD998478: Test Harness
.
Measurement Method
1. Disconnect the camshaft position sensor connector, and
connect the test harness special tool (MB991348) in
between. (All terminals should be connected.)
2. Connect the oscilloscope probe to camshaft position sensor
connector terminal 5.
3. Disconnect the crankshaft position sensor connector, and
connect the test harness special tool (MD998478) in
between.
4. Connect the oscilloscope probe to crankshaft position
sensor connector terminal 2 (black clip of special tool).
.
Alternate method (Test harness not available)
<M/T>
1. Connect the oscilloscope probe to ECM terminal 50. (Check
the camshaft position sensor signal wave pattern.)
2. Connect the oscilloscope probe to ECM terminal 43. (Check
the crankshaft position sensor signal wave pattern.)
<A/T>
1. Connect the oscilloscope probe to PCM terminal 56. (Check
the camshaft position sensor signal wave pattern.)
2. Connect the oscilloscope probe to PCM terminal 45. (Check
the crankshaft position sensor signal wave pattern.)
Standard Wave Pattern
Observation conditions
Function
Special pattern
Pattern height
Low
Pattern selector
Display
Engine r/min
Idle speed
AK102977AB
1 2 3 4 5 6 7
CAMSHAFT POSITION
SENSOR CONNECTOR
OSCILLOSCOPE
MB991348
AK102979AB
MD998478
1 2
3
CRANKSHAFT POSITION
SENSOR CONNECTOR
OSCILLOSCOPE