P1336 - Crankshaft Position (CKP) System Variation Not Learned

The P1336 diagnostic trouble code (DTC) indicates a problem with the crankshaft position (CKP) sensor system. Specifically, it means the engine control module (ECM) hasn't learned the crankshaft position variation, which is crucial for accurate engine timing and performance. This lack of learning can lead to various drivability issues, and prompt diagnosis and repair are essential to prevent further complications.

Comprehensive Information on P1336

Detailed Explanations

Definition: The P1336 code signifies that the vehicle's engine control module (ECM) has not yet learned the variations in the crankshaft's rotational speed during its operation. These variations, even tiny ones, are crucial for the ECM to precisely calculate engine timing and optimize fuel injection. Without this learned variation data, the ECM can't accurately control these functions, leading to performance issues.

Recent ECM Replacement or Reprogramming: When the ECM is replaced or reprogrammed, the crankshaft position variation data is typically erased. This necessitates a crankshaft position variation learn procedure, which uses a scan tool to instruct the ECM to relearn these variations. Failing to perform this procedure after ECM replacement or reprogramming is a common cause of the P1336 code.

Crankshaft Position Sensor Replacement: Replacing the crankshaft position sensor itself can sometimes trigger this code. Even if the new sensor is functioning correctly, the ECM might still need to relearn the crankshaft position variation to accurately interpret the new sensor's signal. The sensor's positioning, even slightly different from the original, can influence the signal.

Camshaft Position Sensor Replacement: While less common, replacing the camshaft position (CMP) sensor can also contribute to a P1336 code. The CKP and CMP sensors work together to provide the ECM with comprehensive information about engine position. If the CMP sensor is replaced, the ECM may need to relearn the relationship between the CKP and CMP signals, which could trigger the need for a CKP variation learn procedure.

Mechanical Engine Problems: Underlying mechanical issues within the engine can prevent the ECM from successfully learning the crankshaft position variation. For example, a worn timing chain can cause inconsistent timing, making it difficult for the ECM to establish a stable reference point. Similarly, excessive crankshaft endplay (the amount of axial movement of the crankshaft) can introduce variations that the ECM cannot compensate for.

Faulty Crankshaft Position Sensor: Although the P1336 code often indicates a lack of learning, a malfunctioning crankshaft position sensor itself can also be the root cause. If the sensor is providing inaccurate or intermittent signals, the ECM may be unable to learn the crankshaft position variation correctly. This is why it's crucial to test the sensor's functionality before proceeding with other diagnostic steps.

Faulty Camshaft Position Sensor: Similar to a faulty CKP sensor, a malfunctioning camshaft position sensor can also interfere with the crankshaft position variation learning process. The ECM relies on both sensors to accurately determine engine position and timing, so a faulty CMP sensor can disrupt the learning process.

Electrical Problems in the CKP/CMP Sensor Circuits: Problems within the electrical circuits connecting the CKP and CMP sensors to the ECM can also trigger the P1336 code. This includes issues like damaged wiring, corroded connectors, or short circuits. These electrical problems can disrupt the sensor signals, preventing the ECM from learning the crankshaft position variation.

Low Battery Voltage: Insufficient battery voltage can sometimes interfere with the ECM's ability to perform the crankshaft position variation learn procedure. The ECM requires a stable voltage supply to function correctly, and low voltage can disrupt its internal processes.

Internal ECM Failure: Although rare, an internal failure within the ECM can also be the cause of the P1336 code. This is usually considered a last resort diagnosis after all other potential causes have been ruled out.

Incorrect or Incomplete Scan Tool Procedures: The crankshaft position variation learn procedure requires a compatible scan tool and the correct procedure. Incorrectly following the procedure or using an incompatible scan tool can result in the procedure failing and the P1336 code persisting.

Presence of other DTCs related to CKP or CMP sensors: The presence of other DTCs related to the CKP or CMP sensors can interfere with the learn procedure. Address all other sensor-related codes first before attempting the CKP learn procedure.

Check Engine Light Illuminated: The most obvious symptom is the illumination of the Check Engine Light on the dashboard. This indicates that the ECM has detected a problem and stored a DTC.

Engine Misfires: Because the ECM cannot accurately determine engine timing, misfires can occur. This happens when the fuel/air mixture is not ignited at the optimal time.

Rough Idling: The engine may idle roughly due to the inaccurate timing and fuel delivery caused by the lack of crankshaft position variation learning.

Stalling: In severe cases, the engine may stall, particularly at idle or during low-speed operation, due to the inability of the ECM to maintain proper engine control.

Difficulty Starting: The engine may be difficult to start, as the ECM struggles to determine the correct timing for ignition and fuel injection during the starting process.

Reduced Engine Performance: Overall engine performance may be reduced due to the inaccurate timing and fuel delivery. The engine may feel sluggish or unresponsive.

Hesitation During Acceleration: The engine may hesitate or stumble during acceleration due to the ECM's inability to optimize fuel delivery and ignition timing.

Decreased Fuel Economy: Inefficient combustion caused by inaccurate timing and fuel delivery can lead to decreased fuel economy.

Engine Knocking or Pinging: In some cases, the inaccurate timing can lead to engine knocking or pinging, which is a rattling or knocking sound coming from the engine.

Scan the ECM for DTCs and record freeze frame data: The first step is to use a scan tool to retrieve any stored diagnostic trouble codes (DTCs) from the ECM. Record the freeze frame data, which provides a snapshot of the engine conditions when the code was set. This data can be helpful in diagnosing the problem.

Inspect CKP and CMP sensors for damage or contamination: Visually inspect the CKP and CMP sensors for any signs of physical damage, such as cracks or broken connectors. Also, check for any contamination, such as oil or debris, that could be interfering with the sensor's operation.

Check CKP and CMP sensor wiring and connectors for damage or corrosion: Carefully inspect the wiring and connectors associated with the CKP and CMP sensors for any signs of damage, such as frayed wires or corroded connectors. These issues can disrupt the sensor signals and trigger the P1336 code.

Verify CKP and CMP sensor signals with an oscilloscope (if possible): If you have access to an oscilloscope, you can use it to verify the CKP and CMP sensor signals. This can help you determine if the sensors are functioning correctly and providing accurate signals to the ECM.

Perform a crankshaft position variation learn procedure with a compatible scan tool: The most common solution to the P1336 code is to perform a crankshaft position variation learn procedure using a compatible scan tool. This procedure instructs the ECM to relearn the crankshaft position variation.

Check for mechanical engine problems: If the crankshaft position variation learn procedure fails, it's important to check for underlying mechanical engine problems, such as a worn timing chain or excessive crankshaft endplay.

Perform a crankshaft position variation learn procedure: This procedure, accessible through a compatible scan tool, instructs the ECM to relearn the crankshaft position variation. It often involves specific steps, such as accelerating the engine to a certain RPM and maintaining it for a set period.

Replace faulty CKP or CMP sensors: If the CKP or CMP sensors are found to be faulty, they should be replaced with new, OEM-quality sensors.

Repair or replace damaged wiring or connectors: Any damaged wiring or connectors in the CKP or CMP sensor circuits should be repaired or replaced to ensure proper signal transmission.

Correct mechanical engine problems: If mechanical engine problems are identified, they must be addressed before the P1336 code can be resolved. This may involve replacing the timing chain, adjusting crankshaft endplay, or other necessary repairs.

Replace the ECM (as a last resort, after thorough diagnosis): Only after all other potential causes have been ruled out should the ECM be considered as the source of the problem. Replacing the ECM should be a last resort.

Ensure battery voltage is within the specified range: Before attempting the CKP variation learn procedure, ensure the battery voltage is within the manufacturer's specified range. A low battery can prevent the procedure from completing successfully.

Frequently Asked Questions

What does the P1336 code mean? It means the ECM hasn't learned the crankshaft position variation, which is needed for accurate engine timing.

What are the common symptoms of P1336? Common symptoms include a check engine light, rough idling, and potential stalling.

Can I drive with a P1336 code? While you can drive, it's not recommended as it can lead to further engine damage and reduced performance.

How do I fix a P1336 code? The most common fix is to perform a crankshaft position variation learn procedure with a scan tool.

Do I need to replace the CKP sensor for P1336? Not necessarily; try the learn procedure first. If that fails, test the sensor before replacing it.

Conclusion

The P1336 code indicates a crankshaft position variation learning issue, often resolved with a relearn procedure. Thorough diagnosis is crucial before replacing parts, focusing on sensor functionality, wiring, and potential mechanical issues. Always consult a repair manual or qualified technician for specific repair procedures for your vehicle.