Camshaft Position Sensor: Testing and Inspection
CAMSHAFT POSITION SENSOR AND CRANKSHAFT POSITION SENSORRequired 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)
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.)
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.)
Wave Pattern Observation Points
1. Check that cycle time T becomes shorter when the engine speed increased.
EXAMPLES OF ABNORMAL WAVE PATTERNS
Example 1
- Cause of problem
Sensor interface malfunction.
- Wave pattern characteristics
Rectangular wave pattern is output even when the engine is not started.
Example 2
- Cause of problem
Loose timing belt. Abnormality in sensor disc.
- Wave pattern characteristics
Wave pattern is displaced to the left or right.
INJECTOR
Required Special Tools:
- MB991348: Test Harness
- MD998464: Test Harness
MEASUREMENT METHOD
1. Disconnect the injector intermediate connector, and connect the test harness special tool (MD998464) in between.
2. Connect the oscilloscope probe to each injector intermediate connector terminal to analyze each cylinder:
- Terminal 2 (black clip of special tool) for the number 1 cylinder
- Terminal 3 (blue clip) for the number 3 cylinder
- Terminal 4 (white clip) for the number 5 cylinder
1. Disconnect the injector connector, and connect the test harness special tool (MB991348) in between. (All terminals should be connected.)
2. Connect the oscilloscope probe to injector connector terminal 2.
Alternate method (Test harness not available)
1. Connect the oscilloscope probe to ECM
2. Connect the oscilloscope probe to ECM
3. Connect the oscilloscope probe to ECM
4. Connect the oscilloscope probe to ECM
5. Connect the oscilloscope probe to ECM
6. Connect the oscilloscope probe to ECM
Wave Pattern Observation Points
Point A: Height of injector coil induced voltage.
Point B: Injector drive time
1. The injector drive time should be synchronized with the scan tool tester display.
2. When the engine is suddenly revved, the drive time will be greatly extended at first, but the drive time will soon return to original length.