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.
2004 Mazda RX8 2RTR-1.3LFACTORY OEM SERVICE PROCEDURE
Throttle Position (TP) Sensor Inspection
THROTTLE POSITION (TP) SENSOR INSPECTION
CAUTION: This inspection procedure cannot be completed correctly if the accelerator pedal position sensor has a malfunction. Before performing this procedure, verify that any one of the DTCs (P1577, P2122, P2123, P2127, P2128, P2138) related to the accelerator pedal position sensor is not detected.
NOTE: Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See FOREWORD.) Flow of Diagnosis
Voltage Inspection
1. Turn the ignition switch to the ON position.
2. Verify that the voltage at PCM terminals 1 J (WDS PID: TP1) and 1 M (WDS PID: TP2) increases while gradually increasing the accelerator pedal opening angle according to the accelerator pedal opening angle.
- If it can be verified, go to the next step.
- If it cannot be verified even though the related wiring harnesses have no malfunction, replace the throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
3. Verify that the voltage at PCM terminals U (WDS PID: TP1) and 1M (WDS PID: TP2) is as indicated in the table.
- If it cannot be verified, replace the throttle body.
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Disconnect the throttle body connector.
3. Inspect the following wiring harnesses for open or circuit. (Continuity inspection)
Open circuit
- If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.
- Throttle body terminal C and PCM terminal 2F
- Throttle body terminal D and PCM terminal 1M
- Throttle body terminal E and PCM terminal 1Q
- Throttle body terminal F and PCM terminal 1J
Short circuit
- If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness.
- Throttle body terminal E and body ground
- Throttle body terminal E and power supply
- Throttle body terminal F and body ground
- Throttle body terminal F and power supply
- Throttle body terminal D and body ground
- Throttle body terminal D and power supply
CAUTION: This inspection procedure cannot be completed correctly if the accelerator pedal position sensor has a malfunction. Before performing this procedure, verify that any one of the DTCs (P1577, P2122, P2123, P2127, P2128, P2138) related to the accelerator pedal position sensor is not detected.
NOTE: Before performing the following inspection, make sure to follow the troubleshooting flowchart. (See FOREWORD.) Flow of Diagnosis
Voltage Inspection
1. Turn the ignition switch to the ON position.
2. Verify that the voltage at PCM terminals 1 J (WDS PID: TP1) and 1 M (WDS PID: TP2) increases while gradually increasing the accelerator pedal opening angle according to the accelerator pedal opening angle.
- If it can be verified, go to the next step.
- If it cannot be verified even though the related wiring harnesses have no malfunction, replace the throttle body. (See INTAKE-AIR SYSTEM REMOVAL/INSTALLATION.)
3. Verify that the voltage at PCM terminals U (WDS PID: TP1) and 1M (WDS PID: TP2) is as indicated in the table.
- If it cannot be verified, replace the throttle body.
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Disconnect the throttle body connector.
3. Inspect the following wiring harnesses for open or circuit. (Continuity inspection)
Open circuit
- If there is no continuity in the following wiring harnesses, there is an open circuit. Repair or replace the wiring harness.
- Throttle body terminal C and PCM terminal 2F
- Throttle body terminal D and PCM terminal 1M
- Throttle body terminal E and PCM terminal 1Q
- Throttle body terminal F and PCM terminal 1J
Short circuit
- If there is continuity in the following wiring harnesses, there is a short circuit. Repair or replace the wiring harness.
- Throttle body terminal E and body ground
- Throttle body terminal E and power supply
- Throttle body terminal F and body ground
- Throttle body terminal F and power supply
- Throttle body terminal D and body ground
- Throttle body terminal D and power supply
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.