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.
2003 Mazda 6 L4-2.3LFACTORY OEM SERVICE PROCEDURE
Accelerator Pedal Position Sensor: Testing and Inspection
ACCELERATOR PEDAL POSITION (APP) SENSOR INSPECTION
NOTE: Perform the following inspection only when directed.
Voltage Inspection
1. Turn the ignition key to ON position (Engine OFF).
2. Verify that the PCM terminal 2A and 3D change smoothly while throttle valve is gradually opened.
- If as verified, go to next step.
- If not as verified, perform the "Circuit Open/Short Inspection".
- If there is no open or short circuit, replace the throttle body.
3. Verify that the PCM terminal 2A and 3D voltages are as shown in the given table.
- If voltage is not as in given table, perform the "Circuit Open/Short Inspection".
- If there is no open or short circuit, replace accelerator pedal.
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for open or short. (Continuity check)
Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- APP sensor terminal A (harness-side) and PCM terminal 2K (harness-side)
- APP sensor terminal B (harness-side) and PCM terminal 2H (harness-side)
- APP sensor terminal C (harness-side) and PCM terminal 2A (harness-side)
- APP sensor terminal D (harness-side) and PCM terminal 3G (harness-side)
- APP sensor terminal E (harness-side) and PCM terminal 3A (harness-side)
- APP sensor terminal F (harness-side) and PCM terminal 3D (harness-side)
Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- APP sensor terminal A (harness-side) and power supply
- APP sensor terminal A (harness-side) and body GND
- APP sensor terminal B (harness-side) and power supply
- APP sensor terminal C (harness-side) and power supply
- APP sensor terminal C (harness-side) and body GND
- APP sensor terminal D (harness-side) and power supply
- APP sensor terminal D (harness-side) and body GND
- APP sensor terminal E (harness-side) and power supply
- APP sensor terminal F (harness-side) and power supply
- APP sensor terminal F (harness-side) and body GND
NOTE: Perform the following inspection only when directed.
Voltage Inspection
1. Turn the ignition key to ON position (Engine OFF).
2. Verify that the PCM terminal 2A and 3D change smoothly while throttle valve is gradually opened.
- If as verified, go to next step.
- If not as verified, perform the "Circuit Open/Short Inspection".
- If there is no open or short circuit, replace the throttle body.
3. Verify that the PCM terminal 2A and 3D voltages are as shown in the given table.
- If voltage is not as in given table, perform the "Circuit Open/Short Inspection".
- If there is no open or short circuit, replace accelerator pedal.
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for open or short. (Continuity check)
Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- APP sensor terminal A (harness-side) and PCM terminal 2K (harness-side)
- APP sensor terminal B (harness-side) and PCM terminal 2H (harness-side)
- APP sensor terminal C (harness-side) and PCM terminal 2A (harness-side)
- APP sensor terminal D (harness-side) and PCM terminal 3G (harness-side)
- APP sensor terminal E (harness-side) and PCM terminal 3A (harness-side)
- APP sensor terminal F (harness-side) and PCM terminal 3D (harness-side)
Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- APP sensor terminal A (harness-side) and power supply
- APP sensor terminal A (harness-side) and body GND
- APP sensor terminal B (harness-side) and power supply
- APP sensor terminal C (harness-side) and power supply
- APP sensor terminal C (harness-side) and body GND
- APP sensor terminal D (harness-side) and power supply
- APP sensor terminal D (harness-side) and body GND
- APP sensor terminal E (harness-side) and power supply
- APP sensor terminal F (harness-side) and power supply
- APP sensor terminal F (harness-side) and body GND
Factory Service Tools
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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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