Throttle Position Sensor: Testing and Inspection

Throttle Sensor Test Harness:

CAUTION: Use a precision voltmeter with a scale of 0.01 volts to inspect or adjust the throttle sensor.

1. Remove air hose from throttle body.
2. Disconnect throttle sensor connector (3-pin).
3. Connect adapter (SST Mazda Part# 49 G018 901) between throttle sensor and wiring harness.
4. Turn ignition switch "ON."
5. Make sure throttle valve is fully closed.

Throttle Sensor Voltage Testing:

6. Measure BLACK and RED wire voltages. The black wire should be approx. 0 volts and the red wire should be 4.5 - 5.5 volts.
7. If not as specified, check battery voltage and wiring harness. If these are OK, replace ECU.
8. Record RED wire voltage.

Throttle Sensor Voltage Testing:

9. Check voltage at BLUE wire and check that it corresponds with RED voltage recorded in step 6 by using the following chart:

RED VOLTS BLUE VOLTS

4.50-4.59 0.37-0.54
4.60-4.69 0.38-0.55
4.70-4.79 0.39-0.56
4.80-4.89 0.40-0.57
4.90-4.99 0.40-0.58
5.00-5.09 0.41-0.60
5.10-5.19 0.42-0.61
5.20-5.29 0.43-0.62
5.30-5.39 0.44-0.63
5.40-5.49 0.44-0.64
5.50 0.44-0.66

Throttle Valve Fully Open:

10. Hold the throttle valve fully open.
11. Check the BLUE and RED wire voltages. Check that the BLUE voltage corresponds with the RED voltage listed in the following table:

RED VOLTS BLUE VOLTS

4.50-4.59 3.58-4.23
4.60-4.69 3.66-4.32
4.70-4.79 3.74-4.41
4.80-4.89 3.82-4.51
4.90-4.99 3.90-4.60
5.00-5.09 3.97-4.70
5.10-5.19 4.05-4.79
5.20-5.29 4.13-4.88
5.30-5.39 4.21-4.98
5.40-5.49 4.29-5.07
5.50 4.29-5.17

12. Check that BLUE wire voltage increases smoothly when opening throttle from closed to fully open.
13. If not as specified, replace throttle sensor.
14. Turn ignition "OFF."
15. Remove test adapter and reconnect sensor connector.
16. Disconnect negative battery terminal and depress brake pedal for at least 5 seconds to eliminate ECU malfunction memory created during inspection.

Throttle sensor input signal can be checked at ECU terminal 2F with ignition switch "ON." With throttle closed, voltage should be approximately 0.5V. This will vary depending on reference voltage at ECU terminal 2I, which should be 4.5 - 5.5V.

With throttle fully open, terminal 2F voltage should be 4.3V.