Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2012 Mazda 3 L4-2.5LFACTORY OEM SERVICE PROCEDURE
Crankshaft Position Sensor: Service and Repair
CRANKSHAFT POSITION (CKP) SENSOR REMOVAL/INSTALLATION [MZR 2.0, MZR 2.5]
Removal
CAUTION:
- When foreign material such as an iron chip is on the CKP sensor, it can cause abnormal output from the sensor because of flux turbulence and adversely affect the engine control. Be sure there is no foreign material on the CKP sensor when replacing.
- Do not assemble the CKP sensor or change the installation position using any method other than the following. Otherwise, it could negatively affect engine controls, such as the ignition timing and fuel injection.
1. Remove the battery cover. Removal and Replacement
2. Disconnect the negative battery cable. Removal and Replacement
3. Perform the following procedure for easier access.
a. Remove the aerodynamic under cover No.2. Aerodynamic Under Cover No. 2 Removal/Installation
b. Remove the front splash shield (RH). Splash Shield Removal/Installation
4. Disconnect the CKP sensor connector.
5. Remove the CKP sensor.
Installation
CAUTION:
- When foreign material such as an iron chip is on the CKP sensor, it can cause abnormal output from the sensor because of flux turbulence and adversely affect the engine control. Be sure there is no foreign material on the CKP sensor when replacing.
- Do not assemble the CKP sensor or change the installation position using any method other than the following. Otherwise, it could negatively affect engine controls, such as the ignition timing and fuel injection.
1. Perform the following procedure so that cylinder No.1 is at TDC.
a. Remove the wheel and tire (front right side).
b. Disconnect the drive shaft (RH) from joint shaft, set the drive shaft (RH) out of the way. (MTX) Drive Shaft Removal/Installation
c. Remove the cylinder block lower blind plug and install the SST.
d. Rotate the crankshaft pulley clockwise until the crank weight contacts the SST so that cylinder No.1 is at TDC.
2. Fit the center of the CKP sensor with the fifth tooth (counting counterclockwise from the empty space A as shown in the figure) of the pulse wheel.
CAUTION:
- If the line is not accurately drawn, ignition timing, fuel injection and other engine control systems will be adversely effected. Draw the straight line carefully using a straight edge.
3. Align the center line of the CKP sensor and the line drawn in Step 2, then install the sensor.
4. Install the CKP sensor fitting bolts.
5. Remove the SST then install the cylinder block lower blind plug.
6. Install the drive shaft (RH). (MTX) Drive Shaft Removal/Installation
7. Install the wheel and tire (front right side).
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
Comes to youSame-day available12-month warranty
Get a Free QuoteNo obligation. See pricing before you book.