A crankshaft position sensor (CKP) is a vital component in your vehicle’s engine management system. It monitors the position and speed of the crankshaft, sending this information to the engine control unit (ECU). The ECU uses this data to control ignition timing and fuel injection. If your CKP sensor fails or needs relearning, the engine may run poorly or not at all. A common issue that requires a crank sensor relearn is a Diagnostic Trouble Code (DTC) P1336, indicating “Crankshaft Position Variation Not Learned.” This guide explains how to perform a crank sensor relearn procedure using a scan tool, specifically focusing on what you need to know about a Crank Sensor Relearn Scan Tool Cts.
Using a Crank Sensor Relearn Scan Tool (CTS)
Most modern vehicles require a crank sensor relearn scan tool CTS to properly relearn the crankshaft position after sensor replacement or other related repairs. This specialized tool allows communication with the vehicle’s ECU to initiate and complete the relearn process. Here’s a general outline of the procedure using a scan tool:
Preparation:
- Safety First: Ensure the vehicle is parked on a level surface, the parking brake is engaged, and the wheels are blocked. Close the hood after verifying necessary components are accessible.
- Temperature Check: Start the engine and let it run until the engine coolant temperature reaches at least 158°F (70°C). This ensures optimal operating conditions for the relearn procedure. Then, turn off the engine for at least 10 seconds.
Relearn Procedure with a Scan Tool:
- Connect the Scan Tool: Connect your crank sensor relearn scan tool CTS to the vehicle’s OBD-II port.
- Initiate CASE Learn: Power on the scan tool and select the “Crankshaft Position Variation Learn” procedure, often referred to as “CASE Learn.”
- Transmission in Park: Ensure the transmission is in Park (or Neutral for manual transmissions).
- Start the Engine: Start the engine and firmly apply the brakes.
- Follow On-Screen Prompts: Carefully follow the specific instructions displayed on your crank sensor relearn scan tool CTS. These instructions will guide you through the process, which typically involves raising the engine speed to specific RPM levels (e.g., 3000, 4000, or 5150 RPM).
Important Note: Pay close attention to the fuel cutoff RPM indicated by the scan tool. Release the throttle immediately when the engine RPM begins to decrease due to fuel cutoff. Failure to do so can result in engine over-revving and potential damage.
- Verification: Once the engine returns to idle, the scan tool will indicate whether the CASE learn was successful. If successful, the P1336 code should clear. If unsuccessful, check for other DTCs and address them before repeating the procedure.
Performing a Crank Sensor Relearn Without a Scan Tool (Certain Applications)
Some older vehicles or specific truck applications (primarily pre-2000) may allow for a crank sensor relearn without a scan tool. This method relies on specific driving cycles to relearn the crankshaft position.
Note: This procedure is not applicable to all vehicles. Consult your vehicle’s repair manual to determine the correct relearn procedure for your specific make and model.
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Prepare the Vehicle: Turn off all accessories. Ensure the air temperature and coolant temperature are within 5°C of each other.
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Driving Cycle: The driving cycle typically involves a series of specific acceleration, cruising, and deceleration steps performed under controlled conditions. This process allows the ECU to learn the crankshaft position variation. Consult your vehicle’s repair manual for the exact steps required for your application.
Conclusion
A crank sensor relearn is essential for proper engine operation after certain repairs or sensor replacements. While a crank sensor relearn scan tool CTS is generally required for modern vehicles, some older models may offer alternative procedures. Always consult your vehicle’s repair manual for the correct procedure and follow safety precautions. If you are uncomfortable performing this procedure yourself, consult a qualified mechanic.
