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 CX-9 FWD V6-3.7LFACTORY OEM SERVICE PROCEDURE
Accelerator Pedal Position Sensor: Testing and Inspection
ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION [MZI-3.7]
NOTE:
- Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart. Description and Operation
- The APP sensor cannot be removed as a single unit. When replacing the APP sensor, replace it together with the accelerator pedal as a single unit.
Voltage Inspection
1. Turn the ignition switch to the ON position (Engine OFF).
2. Verify that the PCM terminal 1Y and 1U change smoothly while throttle valve is gradually opened.
- If as verified, go to the next step.
- If not as verified, perform the "Circuit Open/Short Inspection".
- If there is no open or short circuit, replace the throttle body. Service and Repair
3. Verify that the PCM terminal 1Y and 1U voltages are as shown in the following table.
- If voltage is not as following table, perform the "Circuit Open/Short Inspection".
- If there is no open or short circuit, replace the accelerator pedal. Service and Repair
APP sensor output voltage
Circuit Open/Short Inspection
1. Disconnect the negative battery cable. Removal and Replacement
2. Disconnect the APP sensor connector.
3. Disconnect the PCM connector.
4. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- APP sensor terminal A and PCM terminal 1Z
- APP sensor terminal B and PCM terminal 1U
- APP sensor terminal C and PCM terminal 1AD
- APP sensor terminal D and PCM terminal 1AB
- APP sensor terminal E and PCM terminal 1Y
- APP sensor terminal F and PCM terminal 1X
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- APP sensor terminal A and body ground
- APP sensor terminal B and body ground
- APP sensor terminal B and power supply
- APP sensor terminal C and power supply
- APP sensor terminal D and power supply
- APP sensor terminal E and body ground
- APP sensor terminal E and power supply
- APP sensor terminal F and body ground
Factory Service Tools
Use the Manual With the Right Hardware
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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.
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