Code P1396 Chevrolet: Understanding and Solving the Problem

The diagnostic trouble code P1396 Chevrolet is a generic OBD2 protocol code that indicates an intermittent problem with the crankshaft position sensor (CKP) or the camshaft position sensor (CMP). Specifically, the Powertrain Control Module (PCM) has detected a loss of signal or an inconsistency between the signals from these two sensors, which are essential for the proper operation of the engine. This code is common on many models from the brand, such as the Chevrolet Silverado, Malibu, Impala, or Tahoe. Understanding its cause is crucial to avoid engine performance issues, excessive fuel consumption, or even more serious damage.

Symptoms of Code P1396

When this fault is stored in the PCM’s memory, several symptoms can alert the driver. It is important to note that these signs can be intermittent, especially in the early stages of the problem.

• Engine shaking or misfiring: A loss of synchronization between the camshafts and the crankshaft causes inefficient combustion.
• Starting difficulties: The vehicle may take longer to start, require several turns of the key, or sometimes not start at all.
• Unstable idle: The engine may jerk and its RPM may fluctuate abnormally at idle.
• Loss of power and performance: A feeling of sluggishness during acceleration is common.
• The check engine light illuminates: The famous “check engine” light comes on, often accompanied by the P1396 code.

Possible Causes of the P1396 Fault

Several elements can be the origin of this code. A methodical diagnosis is necessary to identify the exact source of the problem without replacing parts unnecessarily.

• Faulty crankshaft position sensor (CKP): The sensor itself may be defective, have loose internal connections, or be dirty.
• Faulty camshaft position sensor (CMP): Just like the CKP, it can fail.
• Wiring or connector problems: Frayed, corroded, short-circuited, or loose wires between the sensors and the PCM are a very common cause, especially with an intermittent code.
• Poor sensor power supply or ground: A problem in the 5V power supply circuit or ground can distort the signals.
• Problem with the PCM: Although rarer, the control module itself may be faulty.

Diagnostic Procedure and Solutions

Before replacing a sensor, it is imperative to perform a thorough check. Use a scan tool to confirm the code and observe the live data from the CKP and CMP sensors while the engine is running. Look for any loss of signal.

Start with a thorough visual inspection of the wiring and connectors for both sensors. Look for any signs of damage, corrosion, or burning. Check the sensor’s power supply voltage and ground using a multimeter. If the wiring is intact, you can test the sensor resistance (following the specifications in your Chevrolet model’s repair manual) or replace them with quality parts for a substitution diagnosis.

Finally, if the problem persists after replacing the sensors and checking the wiring, a software problem with the PCM or a mechanical timing error (such as a stretched timing chain) could be the cause, although these cases are much less frequent.