Chrysler PT Cruiser 2001 Service Manual Supplement page 2629

Symptom:
P1391-INTERMITTENT LOSS OF CMP OR CKP
When Monitored and Set Condition:
P1391-INTERMITTENT LOSS OF CMP OR CKP
When Monitored: During engine running.
Set Condition: When the expected cam signal level disagrees with the actual cam signal
level.
DAMAGED TONE WHEEL/FLEX PLATE (CRANKSHAFT)
DAMAGED TONE WHEEL/PULSE RING (CAMSHAFT)
IRREGULAR LAB SCOPE PATTERN OF CMP SIGNAL
WIRING HARNESS INTERMITTENT
INTERMITTENT CKP SIGNAL LOSS WHEN WIRING IS WIGGLED
IRREGULAR LAB SCOPE PATTERN OF CKP SIGNAL
INTERMITTENT CMP SIGNAL LOSS WHEN WIRING IS WIGGLED
SENSOR CONNECTOR/WIRING
CAMSHAFT POSITION SENSOR
CRANKSHAFT POSITION SENSOR
TEST
1 Turn the ignition on.
With the DRB, read the DTC's.
Is the Good Trip Counter displayed and equal to zero?
Yes → Go To 2
→ Go To 13
No
2 Turn the ignition off.
With the DRB lab scope, backprobe the CMP signal circuit at the CMP sensor
harness connector using Miller special tool #6801.
Warning: Keep clear of the engine's moving parts.
Start the engine.
Observe the CMP sensor voltage pattern on the lab scope screen.
Are there any signals missing?
Yes → Go To 3
→ Go To 6
No
POSSIBLE CAUSES
ACTION
169
DRIVEABILITY - GAS
APPLICABILITY
All
All