P1394 Ford Unlike Chevrolet, which directly associates it with the VVT system, the P1394 code on Ford vehicles has a slightly different meaning, although just as serious.
- P: Powertrain
- 1394: Intermittent disagreement or loss of signal between the Camshaft Position Sensor (CMP) and the Crankshaft Position Sensor (CKP).
In summary, the Ford Powertrain Control Module (PCM) uses the Crankshaft Position Sensor (CKP) as the primary and absolute reference for piston position. The Camshaft Position Sensor (CMP) acts as a secondary reference that allows the PCM to determine which cylinder is on the compression stroke (this is the “synchronization”).
The P1394 code is triggered when the PCM detects that the signal from the camshaft position sensor is missing, erratic, or out of sync with the crankshaft signal for a certain number of engine revolutions. Without this information, the PCM cannot properly synchronize fuel injection and ignition.
2. Main Symptoms
The appearance of the P1394 code will immediately illuminate the Malfunction Indicator Lamp (MIL). Symptoms are often severe and may include:
- Engine Cranks But Does Not Start (“Crank No Start”): This is the most classic symptom. The PCM, not knowing which cylinder to supply fuel to first, cuts off fuel injection and ignition for safety.
- Engine Starts But Stalls Immediately.
- Random and Significant Misfires on multiple cylinders.
- Extremely Unstable Idle if the engine manages to run.
- Drastic Performance Drop and loss of power.
3. Possible Causes (In Order of Probability)
The causes are often simpler than on a complex VVT system, but just as critical.
- Camshaft Position Sensor (CMP) Failure: This is the most common cause. The sensor is dead or providing a signal that is too weak.
- Wiring and Connector Issues:
- Damaged, chafed, cut, or melted wires leading to the CMP sensor.
- CMP sensor connector improperly connected, corroded, or oxidized.
- Short circuit (to ground or +12V) in the CMP signal circuit.
- Mechanical Timing Issues:
- The timing belt or chain may have jumped one (or more) tooth(s). This is a serious cause that requires immediate resynchronization.
- Excessive wear of timing belt tensioners or guides (for chain-driven engines).
- Powertrain Control Module (PCM) Failure: Extremely rare. It is almost always a problem between the sensor and the PCM.
4. Diagnosis and Troubleshooting (Ford Procedure)
WARNING: Incorrect diagnosis can lead to unnecessary part replacement. The method is crucial.
Recommended tools: OBD2 scanner, digital multimeter (DVOM), Ford diagnostic tool (ideal for viewing live data).
Step-by-step procedure:
- Visual Inspection (Most Important Step):
- Locate the Camshaft Position Sensor (CMP). On most Ford engines, it is located at the front of the engine, on the cylinder head, near the timing cover.
- Disconnect its electrical connector. Inspect it carefully for any signs of corrosion, oxidation (green/white spots), bent pins, or damage.
- Visually inspect the wiring along its entire length, looking for obvious signs of damage.
- CMP Sensor Test (Multimeter):
- Resistance Test (Ohms): Disconnect the sensor. Measure the resistance between the pins of the sensor itself. The value should generally be between 200 and 1,500 Ohms (refer to the repair manual for the exact value for your engine). Infinite resistance (OL) indicates an open sensor. Zero resistance (0 Ohm) indicates an internal short circuit.
- Signal Test (AC Volts): This is the best test. Reconnect the sensor and connect your multimeter leads (in AC Volts mode) to the signal and ground wires by backprobing (without piercing the wire). Have an assistant crank the engine. A functional sensor must produce a small alternating current (AC) voltage of 0.5 to 2 V during cranking. No reading = dead sensor.
- Checking Power and Ground:
- With the ignition on (engine off), disconnect the CMP sensor connector.
- Use your multimeter (in DC Volts) to check for the presence of 12V (or sometimes a 5V reference) and a good ground on the power supply pins of the vehicle-side connector. Absence of voltage = wiring problem to the PCM.
- Mechanical Check (If everything seems electrically good):
- If the code persists after replacing a good sensor, it is imperative to check the alignment of the timing marks (belt or chain) to ensure it has not jumped a tooth. This often requires removing the timing cover.
5. Common Repairs and Approximate Costs
- Replacement of the Camshaft Position Sensor (CMP): This is the solution in 80% of cases.
- Part: €50 – €150
- Labor: 0.5h – 1h (access is generally easy).
- Wiring Repair / Connector Replacement:
- Cost mainly labor (1h – 2h).
- Timing Resynchronization:
- If the belt/chain has jumped, it needs to be reset. High cost (€500 – €1200+) because labor is intensive.
Conclusion:
On a Ford, the P1394 code is a critical code that often prevents the engine from starting. It indicates a loss of the essential synchronization signal provided by the Camshaft Position Sensor (CMP).
The approach is simple:
- Inspect the connector and wiring.
- Test and very likely replace the CMP sensor.
Remember to clear the codes with a scanner after the repair and take a test drive to ensure the fault does not return. If the problem persists after replacing a quality sensor, the mechanical check of the timing is the next step.