P1391 on Jeep
Loss of Cam/Crank Position Sensor Signal — Intermittent Condition
P1391 on Jeep vehicles indicates loss of cam/crank position sensor signal — intermittent condition. Au7o has documented this code across 1 Jeep model — most commonly on Liberty. P1391 is a manufacturer-specific code used primarily by Chrysler, Dodge, and Jeep indicating an intermittent loss of signal from the camshaft position (CMP) sensor or crankshaft position (CKP) sensor. The PCM uses these signals to determine engine timing for ignition and fuel injection, so a dropout can cause hesitation, stalling, or a no-start condition. Note that on a few other makes (e.g., some Chevrolet/GM applications) P1391 can instead refer to a wheel-speed/G-sensor circuit fault. Typical repair costs on Jeep range from $120 to $600, depending on the specific model and root cause.
Common Causes of P1391
- •Failing crankshaft position (CKP) sensor — often drops out when hot, then recovers when cool
- •Failing or intermittent camshaft position (CMP) sensor
- •Damaged, corroded, or loose sensor wiring/connectors or a poor ground
- •Low-quality aftermarket (non-OEM) cam/crank sensor causing the code to return after repair
- •Damaged tone/reluctor wheel teeth on the crankshaft, camshaft, or flexplate
- •Intermittent open or short in the sensor signal circuit to the PCM
P1391 on Jeep by Model
Jeep Liberty(1 issue)
- Crankshaft Position Sensor / Reference Signal Loss - Stalling While Driving and Intermittent No-Start2002-2012
Libertys of both generations lose the crank reference signal to the PCM, setting P0320 and shutting the engine off without warning - owners describe the vehicle simply dying at speed, sometimes restarting immediately and sometimes not for hours, and often producing a limp-mode condition. The fault is heat-sensitive, so it typically appears after the engine is warmed and is hard to reproduce cold at a shop. The forum record contains a real diagnostic warning: on Chrysler powertrains, crank and cam sensor codes are misleading, and the failure is frequently in the connector or the harness (oil-contaminated pins, chafed wiring) or in the PCM rather than in the sensor itself - multiple owners report P0320 returning immediately after a new sensor. Stalling in traffic makes this a safety issue, not just a driveability complaint.
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View P1391 across all makes →Frequently Asked Questions
What does P1391 mean on Jeep?▼
P1391 stands for "Loss of Cam/Crank Position Sensor Signal — Intermittent Condition." P1391 is a manufacturer-specific code used primarily by Chrysler, Dodge, and Jeep indicating an intermittent loss of signal from the camshaft position (CMP) sensor or crankshaft position (CKP) sensor. The PCM uses these signals to determine engine timing for ignition and fuel injection, so a dropout can cause hesitation, stalling, or a no-start condition. Note that on a few other makes (e.g., some Chevrolet/GM applications) P1391 can instead refer to a wheel-speed/G-sensor circuit fault. On Jeep specifically, this code is documented across 1 model.
What causes P1391 on Jeep vehicles?▼
Common causes on Jeep: Failing crankshaft position (CKP) sensor — often drops out when hot, then recovers when cool, Failing or intermittent camshaft position (CMP) sensor, Damaged, corroded, or loose sensor wiring/connectors or a poor ground, Low-quality aftermarket (non-OEM) cam/crank sensor causing the code to return after repair, Damaged tone/reluctor wheel teeth on the crankshaft, camshaft, or flexplate. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P1391 on a Jeep?▼
Repair costs on Jeep range from $120 to $600, depending on the specific model and root cause.
Which Jeep models have P1391 documented?▼
Au7o has documented P1391 on 1 Jeep model: Liberty.