(Crankshaft/Camshaft Sensor Synchronization Issue)
The synchronization between the crankshaft sensor and the camshaft is essential for the proper functioning of the engine. If these sensors do not work correctly, it can lead to poor performance and even potential engine damage.
It is crucial to understand the implications of an error code like the Dodge Code P1391, as it can affect various aspects of vehicle driving and maintenance.
The error code Dodge Code P1391 is often associated with this problem.
When reported, the Dodge Code P1391 can also suggest that there is an underlying issue that requires immediate attention to avoid higher repair costs in the long term.
During diagnosis, the Dodge Code P1391 must be taken into account.
Meaning of Dodge Code P1391
This error code is an indicator of potential problems that can affect the overall operation of your vehicle. Understanding the meaning of this code is vital for proper diagnosis.
It is important to note that intermittent signal loss can also be caused by issues with the connectors, or even failures due to normal component wear.
- Fault: Intermittent loss of signal between the crankshaft sensor (CKP) and the camshaft sensor (CMP).
- Consequence: The Powertrain Control Module (PCM) cannot synchronize injection and ignition → Risk of stalling, hard starting.
- Affected Models:
- Dodge Grand Caravan, Durango, Ram
- Charger, Challenger (V6/V8 HEMI)
- Journey, Nitro
Common Symptoms
| Symptom | Severity |
|---|---|
| Engine shaking at idle | ⚠️ Urgent |
| Misfires during acceleration | ⚠️ Urgent |
| Check engine light on (or flashing) | ⚠️🔧 Immediate Check |
| Sudden engine shutdown | 🛑 STOP (risk of breakdown) |
These vehicles may encounter various other technical issues that can also contribute to the recurrence of the Dodge Code P1391. Regular maintenance is therefore advised to prevent these problems.
If you experience any of these symptoms, it is recommended to have your vehicle checked by a professional as soon as possible. Ignoring these signs can lead to more serious damage.
Main Causes
Studies show that sensor problems can also be aggravated by extreme weather conditions, making maintenance even more crucial.
- Electrical Problems (70% of cases):
- Cut/chewed wires near the sensors (often exposed to heat).
- Oxidized or loose connectors (CKP/CMP).
- Blown fuse (check the under-hood fuse box).
- Sensor Failure:
- Dead CKP or CMP (test resistance: CKP 200–1000Ω / CMP 150–900Ω).
- Metal buildup on the sensor (magnetized by debris).
- Mechanical Problems:
- Improperly tensioned/misaligned timing belt (on belt-driven engines).
- Damaged crankshaft reluctor wheel.
Quick Diagnosis (Key Steps)
- OBD2 Scanner:
- Check for associated codes (e.g., P0340 = CMP / P0335 = CKP).
- Observe live signals: the CMP should synchronize after 2 crankshaft revolutions.
- Physical Inspection:
- Locate the sensors:
CKP: Near the flywheel (transmission side).
CMP: On the cylinder head (rear or front of the engine). - Check cables and connectors (disconnect the battery first!).
- Locate the sensors:
- Electrical Test:
- Supply voltage: 5V or 12V (refer to workshop manual).
- Resistance out of circuit (disconnect the connector).
Effective Repairs
| Solution | Estimated Cost (€) |
|---|---|
| Replace CMP or CKP sensor | 70–150 € (part) |
| Repair damaged wiring harness | 50–120 € |
| Clean metal debris | Free (compressed air) |
| Replace timing belt | 400–700 € |
| Reprogram PCM | 100–200 € (dealership) |
Typical Dodge Case: On *Grand Caravan 3.3L/3.8L*, an oxidized CMP connector under the air intake often triggers the P1391.
Mistakes to Avoid
- Ignoring the timing belt: A misaligned timing system will reactivate the code.
- Forgetting the battery: Low voltage (<12V) distorts signals → Test it first!
- Neglecting connectors: Clean them with contact cleaner before replacing a sensor.
Emergency & Tips
- If the engine stalls or the light flashes: Stop the vehicle → Risk of catalytic converter damage.
- Temporary solution: Turn off/restart the engine (the PCM may resynchronize the sensors).
ℹ️ Technical Reference: Specific procedure in the Dodge DSMS/DealerCONNECT manual for your model. If the code returns after repair, check the ASD Relay (Automatic Shutdown Relay).
Understanding these symptoms will help you better anticipate and react to problems that may arise with your vehicle, especially in the case of the Dodge Code P1391.
Effective repairs also involve systematically checking related parts, as simply replacing a faulty part may not be enough to solve the underlying problem.
It is essential to conduct a thorough analysis of each symptom to identify the real causes of the problems and avoid unnecessary repairs.
Finally, if the Dodge Code P1391 persists after repairs, consult a qualified technician for a more in-depth evaluation and to ensure all potential causes have been addressed.