How to Reset a Crankshaft Position Sensor

There is usually no “reset button” on a crankshaft position sensor itself; instead, you resolve crankshaft sensor issues by fixing wiring or sensor faults, then clearing fault codes and, on many modern vehicles, performing a relearn or adaptation procedure using a scan tool or prescribed pedal/ignition steps. The exact method depends heavily on the vehicle’s make, model, and engine management system.

What the Crankshaft Position Sensor Actually Does

The crankshaft position sensor (often abbreviated CKP) is a critical engine management component that monitors the crankshaft’s speed and position. The engine control unit (ECU) uses this data to time fuel injection and ignition. If the signal is faulty or absent, many engines will not start at all, or will run very poorly.

Key functions of the crankshaft position sensor

The following points highlight why the crankshaft sensor is so central to modern engine operation.

• Engine timing: Provides reference for ignition timing and fuel injection timing.
• RPM measurement: Feeds accurate engine speed data to the ECU.
• Synchronization with camshaft: Works with the camshaft sensor to identify which cylinder is on the power stroke.
• Misfire detection: Helps the ECU detect misfires using subtle changes in rotational speed.
• Safety and limp modes: A missing or erratic signal can trigger limp-home modes or stall-prevention strategies.

Together, these functions mean that any disruption in the crankshaft sensor signal can shut down an engine or make it unreliable, which is why simply “resetting” the sensor without diagnosis is rarely effective.

Can You Actually Reset a Crankshaft Sensor?

In most vehicles, the crankshaft position sensor itself is a passive device with no internal memory. You do not reset the sensor in the same way you might reset a computer. Instead, you reset or relearn the ECU’s interpretation of the sensor’s signal after repair or replacement.

What “reset” usually means in practice

When people talk about resetting a crankshaft sensor, they typically mean one or more of the following actions.

• Clearing diagnostic trouble codes (DTCs): Using an OBD-II scanner to erase codes related to crankshaft position (e.g., P0335, P0336).
• Performing a crankshaft variation relearn: Using a scan tool or a manufacturer-specific procedure so the ECU recalibrates to the new or corrected signal.
• Power-cycling the ECU: Disconnecting the battery for a short time so the ECU clears volatile memory and adaptation values.
• Completing a drive cycle: Following prescribed driving patterns so the ECU can re-learn and re-validate the sensor signals.

These steps do not change the sensor but rather reset the ECU’s stored information and calibrations associated with that sensor’s signal.

Common Signs You Might Be Dealing With a Crankshaft Sensor Issue

Before attempting any kind of reset or relearn, it’s important to confirm that your symptoms actually point toward a crankshaft sensor or related circuit issue.

• Intermittent stalling: Engine shuts off unexpectedly, often when hot, and may restart after cooling.
• No-start condition: The starter cranks but the engine will not fire, especially if no RPM signal shows on a scan tool.
• Rough idle or misfires: Poor idle quality, hesitation, and misfire codes that correlate with CKP/CMP (camshaft) codes.
• Check engine light: Codes such as P0335 (Crankshaft Position Sensor “A” Circuit) or P0336 (range/performance) stored in the ECU.
• Loss of power or limp mode: ECU may limit power or RPM when it detects erratic crankshaft data.

These symptoms can mimic other faults such as failing ignition coils, fuel issues, or camshaft sensor problems, so proper diagnosis is crucial before attempting resets or replacements.

Safety and Preparation Before Any Reset or Repair

Working around the engine and electrical system requires basic safety precautions and a bit of preparation, especially when you’re dealing with starting issues and sensors near rotating components.

• Park safely: Work on a flat surface, engage the parking brake, and keep the transmission in Park (automatic) or Neutral (manual).
• Disconnect battery when handling wiring: Remove the negative terminal before unplugging sensors to avoid shorts.
• Let the engine cool: Crank sensors are often mounted near the crank pulley, flywheel, or transmission bellhousing, which can stay hot.
• Use proper tools: A quality OBD-II scanner, basic hand tools, and a multimeter (for advanced checks) are highly recommended.
• Follow service information: When possible, consult your vehicle’s service manual or a reputable database for exact procedures.

Taking these steps reduces the chance of injuring yourself or causing additional damage while you work on the crankshaft sensor or related systems.

Step-by-Step: How to “Reset” a Crankshaft Sensor the Right Way

While exact sequences vary by make and model, most modern vehicles follow the same general logic: diagnose, repair, clear codes, and then perform a relearn procedure if required.

1. Confirm the Problem with a Scan Tool

Diagnosis comes first; skipping it can lead to unnecessary parts replacement and persistent issues.

1. Connect an OBD-II scanner: Plug the scanner into the OBD-II port (usually under the dashboard near the steering column).
2. Read stored and pending codes: Look specifically for crankshaft-related codes such as P0335–P0339, and note any camshaft sensor or misfire codes.
3. Check live data: If available, monitor engine RPM while cranking; a reading of 0 RPM with a cranking engine often indicates a CKP signal problem.
4. Record freeze-frame data: Capture the conditions under which the fault was stored (engine load, RPM, temperature) for context.

This initial step helps you separate true crankshaft sensor faults from other issues that might produce similar symptoms.

2. Inspect the Sensor and Wiring

Many crankshaft sensor issues are caused by physical or wiring problems rather than sensor electronics themselves.

1. Locate the sensor: It is often found near the crank pulley, flywheel, or on the transmission bellhousing aligned with the flexplate or tone wheel.
2. Inspect wiring and connector: Look for frayed wires, oil-soaked harnesses, loose connectors, or corrosion on terminals.
3. Check sensor mounting: Verify that the sensor is properly seated, with correct air gap from the tone ring, and that mounting bolts are tight.
4. Look for physical damage: Cracked housings, broken mounting tabs, or damage from debris can all compromise the signal.

If you find any visible defects, simply “resetting” won’t fix the problem; physical repair or replacement is required before any software reset will succeed.

3. Replace the Crankshaft Sensor if Necessary

If diagnostics indicate a failed sensor or damaged connector and wiring, replacement is often the next step.

1. Disconnect the battery: Remove the negative terminal to prevent short circuits.
2. Unplug the sensor connector: Release any locking tabs carefully to avoid breaking them.
3. Remove mounting bolts: Take note of any shims or spacers that affect sensor depth or air gap.
4. Install the new sensor: Match the orientation exactly and torque bolts to the manufacturer’s specification.
5. Reconnect the harness: Ensure the connector clicks into place and re-route wiring away from hot or moving parts.

Once the sensor is physically replaced and properly installed, the ECU still needs to be updated or relearned in many vehicles so it can adapt to the new signal characteristics.

4. Clear Fault Codes and Adaptations

Clearing codes is the most basic form of “reset” and is essential after any repair to verify whether the problem is resolved.

1. Reconnect the battery: Confirm that all work is complete and terminals are tight.
2. Turn ignition to ON (engine off): This powers the ECU and the OBD port.
3. Use the scan tool to clear codes: Navigate to the diagnostic menu and erase stored and pending DTCs.
4. Cycle the ignition: Turn the key or start/stop button off and then back on, then check whether any codes immediately reappear.

If codes return immediately without starting the engine, further wiring or sensor checks are needed; if not, you can move on to relearn or drive cycle steps.

5. Perform a Crankshaft Variation Relearn (If Required)

Many modern vehicles require a crankshaft variation relearn after sensor replacement so the ECU can accurately interpret the new sensor’s signal and detect misfires correctly.

1. Check service information: Confirm whether your make/model requires a CKP relearn and whether it needs a professional scan tool.
2. Warm up the engine: Most procedures require the engine to reach normal operating temperature.
3. Connect a capable scan tool: Access functions like “Crankshaft Variation Relearn” or similar terminology.
4. Follow on-screen prompts: The tool may instruct you to hold the brake, put the car in Park/Neutral, and gradually raise engine speed to a specified RPM.
5. Complete the procedure: Once the relearn is done, the scan tool will confirm; then recheck for stored codes.

This relearn does not reset the sensor itself but updates the ECU’s internal tables so it can correctly map and monitor crankshaft rotation with the new or corrected signal.

6. Use a Manual Relearn or Drive Cycle (For Some Models)

Certain vehicles allow limited adaptation without a dedicated relearn function, relying instead on basic driving or ignition sequences to recalibrate sensor interpretation.

1. Ignition key cycles: Some manufacturers specify a number of key ON–OFF cycles with timed intervals to reset adaptations.
2. Idle and low-speed driving: A few minutes of stable idle followed by gentle driving (varied RPM and light load) can help the ECU rebuild learned data.
3. Specific drive cycle: Service literature may outline a pattern (e.g., city/highway mix, specified speeds) to confirm readiness monitors and sensor stability.
4. Monitor with a scanner: Check that no new CKP-related codes appear during or after the drive cycle.

While less precise than a dedicated variation relearn, these methods can allow the ECU to gradually adapt to a new or recently repaired crankshaft sensor in vehicles that support such behavior.

Battery Disconnect as a Basic “Reset” – What It Does and Doesn’t Do

Many owners try disconnecting the battery as a quick reset method; this can help in some cases but has clear limitations.

• What it can do: Clear some temporary adaptations and reset learned idle or fuel trims on certain vehicles.
• What it cannot do: Fix a bad sensor, repair damaged wiring, or perform a true crankshaft variation relearn on systems that require a scan tool.
• Side effects: May erase radio presets, clock settings, and can trigger anti-theft lockouts on some stereos or navigation units.
• Safe method: If you try this, disconnect the negative terminal for around 10–15 minutes, then reconnect firmly and reinitialize any systems as needed.

Battery disconnection should be viewed only as a supporting step, not a substitute for proper diagnosis, repair, and official relearn procedures.

When You Should Not Attempt a DIY Reset

There are situations where home methods are risky or inappropriate, and professional help is strongly advised.

• Persistent no-start condition: If the engine will not start at all after basic checks, further testing with advanced equipment is needed.
• Multiple related codes: A cluster of camshaft, crankshaft, and timing-related codes may suggest mechanical timing issues, not just a sensor fault.
• Timing belt/chain concerns: If there is any suspicion of stretched chains, slipped timing, or internal engine noise, do not rely on simple resets.
• Lack of appropriate tools: If your vehicle explicitly requires a scan-tool relearn and you do not have access to one, avoid “guesswork” methods.

In these cases, a qualified technician with factory-level diagnostics can save time, money, and potentially prevent serious engine damage.

Practical Tips and Best Practices

A few practical habits can improve the odds that your crankshaft sensor and related systems continue to operate reliably after any reset or repair.

• Use quality parts: OEM or high-quality aftermarket sensors are far more reliable than the cheapest options.
• Protect wiring: Keep harnesses away from exhaust components and rotating parts, using proper clips and heat shields.
• Keep the engine clean: Excessive oil leaks can degrade wiring insulation and connectors near the crank area.
• Document procedures: Note what steps you performed and what codes were present; this will help if further diagnosis is required.

Applying these best practices both during and after repair reduces the chance of recurring crankshaft sensor codes or hard-to-trace intermittent faults.

Summary

There is no direct “reset” function on a crankshaft position sensor itself. Instead, you resolve CKP-related issues by diagnosing sensor and wiring faults, replacing or repairing components as needed, then clearing diagnostic codes and performing any required crankshaft variation relearn or drive cycle so the ECU can recalibrate to the sensor’s signal. While some basic resets—like disconnecting the battery or clearing codes—can be done at home, many modern vehicles need a capable scan tool and manufacturer-specific procedures to complete the process reliably. When in doubt, especially with persistent no-start or multiple timing-related codes, professional diagnostics are the safest path.

How do you relearn the crankshaft position sensor without a scanner?

To relearn a crankshaft position sensor without a scanner, you can either disconnect the battery to reset the ECU and let it idle, or perform a specific drive cycle to calibrate the system. The battery method involves disconnecting the negative terminal for at least 15 minutes, reconnecting it, and allowing the engine to idle for 10-15 minutes. The drive cycle method requires warming up the engine, then driving at steady speeds (like 55 mph) for a set period, followed by a specific sequence of decelerations and accelerations. 
Method 1: Battery disconnect and idle 
This video explains how to reset a crankshaft position sensor by disconnecting the battery: 55sMystery Mechanic YouTube · Jun 13, 2025

1. Disconnect the battery: Turn off the engine and disconnect the negative battery terminal for at least 15 minutes. 
2. Discharge the system: With the battery disconnected, press and hold the brake pedal for about 30 seconds to discharge any residual power. 
3. Reconnect the battery: Reconnect the negative battery terminal. 
4. Start and idle: Start the engine and let it idle for 10-15 minutes, or until it reaches operating temperature. The engine may run rough initially as it relearns the sensor values. 

Method 2: Drive cycle

1. Prepare the vehicle: Disconnect the negative battery terminal for 15 minutes. Reconnect it. Make sure all accessories are off and the engine is at least within 5∘5 raised to the composed with power5∘C of the air temperature sensor reading. 
2. Initial idle: Start the engine and let it idle in park or neutral for about two minutes. 
3. Steady speed cruising: Accelerate to 55 mph at part throttle. Cruise at 55 mph for 8-10 minutes until the engine reaches its operating temperature, then continue cruising for another 5-6 minutes. 
4. Deceleration and acceleration:
   • Decelerate to 45 mph without using the brakes and maintain that speed for one minute. 
   • Perform four cycles of decelerating for 25 seconds each. After each deceleration, accelerate back to 45 mph and maintain that speed for 15 seconds. 
   • Finally, accelerate to 55 mph and cruise for two minutes. 
5. Final idle: Come to a stop and let the vehicle idle for two minutes. For automatic transmissions, keep it in Drive with the brake on. For manual transmissions, shift to neutral and depress the clutch. 

Important considerations

• Check for damage: Before attempting any relearn procedure, inspect the sensor and wiring harness for any signs of corrosion or damage, as this can cause persistent issues even after a relearn. 
• Engine temperature: The engine needs to reach its normal operating temperature for most drive cycle relearns to work correctly. 
• Vehicle variations: Some vehicles may require a scan tool for certain relearn procedures, especially newer models or after certain repairs like replacing the ECU. 
• Persistent issues: If the problem continues after trying these methods, the sensor itself may be faulty or there could be an underlying issue that requires professional diagnosis. 

Does a crankshaft position sensor need to be programmed?

No, most new crankshaft sensors do not require programming; they are “plug-and-play” and should work after installation. However, some modern vehicles require a “relearn” procedure using a professional-grade OBD-II scanner to sync the new sensor with the ECU. This procedure accounts for mechanical wear and tolerances, and it may be necessary to visit a dealership or use a high-end scan tool if a simple drive cycle doesn’t work. 
This video explains what to do after replacing a crankshaft position sensor: 59sHVAC Mechanic YouTube · Feb 22, 2023
When programming might be necessary

• Advanced vehicles: Some modern cars need a “relearn” procedure that can only be done with a specialized scan tool. 
• Manufacturer recommendations: Certain manufacturers, like GM, specify that their genuine parts may require programming or a special setup procedure, which can be done by a professional. 
• Significant engine work: A relearn procedure may also be necessary if the crankshaft sensor was replaced as part of other work, such as replacing the timing chain or getting a new cylinder head. 

What to do after replacing the sensor

1. Install the sensor: Physically install the new sensor. 
2. Clear trouble codes: After installation, use an OBD-II scanner to clear any stored diagnostic trouble codes. 
3. Perform a drive cycle: In many cases, simply driving the vehicle can allow the ECU to automatically recalibrate itself. 
4. Use a scan tool for a relearn (if needed): If the vehicle continues to have issues, use a professional scan tool to perform the “crank relearn” or “crankshaft position variation learn” procedure. 
5. Consult a professional: If you don’t have the necessary tools or are unsure, it is best to have a professional mechanic perform the relearn procedure at a dealership or a shop with the right equipment. 

What to do after changing a crankshaft position sensor?

After replacing a crankshaft sensor, you should reset the ECU by clearing codes with an OBD-II scanner or by disconnecting the battery, then perform a short test drive to check for smooth acceleration and idle. For some vehicles, a specific relearn procedure may be necessary, which can sometimes be done through a scan tool or by following a manual process that can be found by searching your vehicle’s make and model. 
Essential post-replacement steps

• Reset the ECU: Disconnect the negative battery terminal for a few minutes or use an OBD-II scanner to clear the codes. This allows the car’s computer to recognize the new sensor. 
• Start the engine: After reconnecting the battery, start the engine and listen to the idle. It should be steady and smooth, not rough or stumbling. 
• Check for codes: Use an OBD-II scanner to confirm there are no new trouble codes. The check engine light should be off. 

This video explains how to replace a crankshaft sensor on a Honda Accord: 1mTRQYouTube · May 1, 2025
Perform a test drive 

• Short test drive: Take a short drive to check for hesitation or stumbling during acceleration. 
• Monitor performance: Watch the tachometer to ensure the RPMs are steady while driving. 
• Check for new issues: Pay attention to the dashboard to ensure the check engine light doesn’t come back on. 

Important considerations

• Specific relearn procedures: Some vehicles require a special relearn or calibration procedure for the new sensor to work correctly. 
• How to find a relearn procedure: Search online for a relearn procedure specific to your vehicle’s year, make, and model, as these can vary widely. 
• Scan tool relearn: An advanced OBD-II scan tool may have a built-in function to perform this procedure. 
• Possible underlying issues: If the car still runs poorly or fails to start, the problem could be a different issue, such as a faulty new sensor, a problem with the wiring, or a timing chain issue. 

This video shows how to reset the crankshaft position sensor relearn on a Honda Accord: 44sMotorcar Parts of America – MPAYouTube · Mar 5, 2025

How do you reset a crankshaft sensor?

Park your vehicle or shift it to neutral and remain still for 2 minutes. Shift your car to part throttle and accelerate to 55mph. Drive around and maintain a speed of 55mph for 10 minutes to let your engine reach its operating temperature. Drive around at 55mph for 5 more minutes.