Throttle Position Sensor: Adjustments

IDLE SPEED CONTROL AND THROTTLE POSITION SENSOR ADJUSTMENT

Adjustment Conditions

- Engine coolant temperature: 85 - 95°C (185 - 205°F)
- Lights, electric cooling fan and accessories: Set to OFF
- Transaxle: Neutral (P for A/T)
- Steering wheel: Neutral position (vehicles with a power steering)

1. Slacken the accelerator cable enough.
2. Connect a tachometer.




3. Connect a digital voltmeter between terminal 19 (throttle position sensor output voltage) of the engine control unit and terminal 24 (ground).
4. Set the ignition switch at ON (without starting the engine), hold it in that position for more than 15 seconds or more.
5. Set the ignition switch at OFF.




6. Disconnect the connectors of the idle speed control servo and lock the idle speed control plunger at the initial position.
7. Back out the fixed SAS enough.
8. Start the engine and let it run at idle.
9. Check to ensure that the engine is running at the standard basic idle speed.
Basic idle speed: 750 ± 50 rpm

Caution:
1. On a new vehicle [driven less than 500 km (300 miles)], the engine speed may be 20 to 100 rpm lower, but no adjustment is necessary.
2. If the engine stalls or the engine speed is low after the vehicle has been driven a distance of 500 km (300 miles) or more, a deposit on the throttle valve area is suspected. Clean the throttle valve area.




10. If the engine speed does not conform to the standard value, adjust it with the idle speed control adjusting screw.

Caution: When adjusting the idle speed control, use a hexagon wrench whenever possible.

11 Turn in the fixed SAS until the engine speed rises. Then back out the fixed SAS until the "touch point" where the engine speed does not fall any longer is found. Back out the fixed SAS an additional half a turn from the touch point.
12. Stop the engine.
13. Set the ignition switch at ON (do not start the engine) and check that the output voltage from the throttle position sensor is as specified.
Standard value: 0.48 - 0.52 V




14. If it is out of specification, adjust by loosening the throttle position sensor mounting screws and rotating the throttle position sensor. After adjustment, tighten the screws firmly.

NOTE: Clockwise rotation ot the throttle position sensor increases the output voltage.

15. Set the ignition switch at OFF.
16. Adjust the free play of the accelerator cable.
17. Reconnect the connectors of the idle speed control servo.
18. Remove the voltmeter.
19. Start the engine and check that the engine is running at the curb idle speed.
Curb idle speed: 750 ± 100 rpm
20. Set the ignition switch at OFF, disconnect the negative battery cable and reconnect it more than 10 seconds later. (By doing so, the memory storing the diagnosis data during the idle speed control adjustment is cleared.)
21. Restart the engine, let it run at idle for about 5 minutes, and check that the engine is running in good idle quality.