Chrysler PT Cruiser 2001 Service Manual Supplement page 2631

P1391-INTERMITTENT LOSS OF CMP OR CKP —
TEST
8 Turn the ignition off.
Disconnect and remove the crankshaft position sensor.
Inspect the crankshaft notches for damage, foreign material, or excessive movement.
Is the crankshaft free from defects?
Yes → Go To 9
No
9 If there are no possible causes remaining, view repair.
Repair
10 Turn the ignition off.
Visually inspect the related wire harness connectors. Look for broken, bent,
pushed out, or corroded terminals.
Visually inspect the related wiring harness. Look for any chafed, pierced,
pinched, or partially broken wires.
Note: Make sure the Camshaft Position Sensor and/or the Crankshaft
Position Sensor is tight.
Note: Refer to any technical service bulletins that may apply.
Were any problems found?
Yes → Repair as necessary.
No
11 Turn the ignition off.
With the DRB lab scope, backprobe the CKP signal circuit at the PCM connector
using Miller special tool #6801.
Warning: Keep clear of the engine's moving parts.
Start the engine.
Observe the lab scope screen while wiggling the wiring harness and connectors
related to the CKP sensor.
Were there any irregularities in the lab scope pattern when the wiggle test was
conducted?
Yes → Note where wiggling caused a missing CKP sensor signal. Repair
No
12 Turn the ignition off.
With the DRB lab scope, backprobe the CMP signal circuit at the PCM harness
connector using Miller special tool #6801.
Warning: Keep clear of the engine's moving parts.
Start the engine.
Observe the lab scope screen while wiggling the wiring harness and connectors
related to the CMP sensor.
Were there any irregularities in the lab scope pattern when the wiggle test was
conducted?
Yes → Note where wiggling caused a missing CMP sensor signal. Repair
No
ACTION
→ Repair/replace tone wheel/flex plate as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Replace the Crankshaft Position Sensor.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
→ Go To 11
CKP sensor wiring as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
→ Go To 12
CMP sensor wiring as necessary.
Perform POWERTRAIN VERIFICATION TEST VER - 5.
→ Test Complete.
DRIVEABILITY - GAS
Continued
171
APPLICABILITY
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All
All
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All