Throttle Position Sensor: Testing and Inspection

Fig. 27 Throttle Sensor Testing:

CAUTION:Use a precision voltmeter with a scale of .01 volts to inspect or adjust throttle sensor.
1. Remove air hose from throttle body.
2. Disconnect throttle sensor 3 pin connector.
3. Connect tool 49G018901 or equivalent between throttle sensor and wiring harness.
4. Turn ignition switch to On position.
5. Ensure throttle valve is fully closed.
6. Measure voltages of black and red wires Fig. 27. Voltage of black wire should be approximately zero volts and voltage of red wire should be 4.5---5.5 volts.
7. If voltages are not as described, check battery voltage and wiring harness and, if battery voltage and wiring harness are satisfactory, replace engine control unit.
8. Record voltage of red wire.

Fig. 28 Meter Hookup:

9. Ensure voltage of blue wire, Fig. 28, is voltage of red wire times .08 to voltage of red wire times .12.
10. If voltage of blue wire is not as described, adjust throttle sensor.
11. Hold throttle valve fully open.
12. Ensure voltage of blue wire is voltage of red wire times .78 to voltage of red wire times .94.
13. If voltage of blue wire is not as described, replace throttle sensor.
14. Turn ignition switch off.
15. Disconnect tool and reconnect throttle sensor connector.
16. Disconnect negative battery terminal and depress brake pedal for at least 5 seconds to eliminate control unit malfunction memory.
17. Adjust throttle sensor, if necessary, as follows:
a. Remove air hose from throttle body.
b. Disconnect throttle sensor 3 pin connector.
c. Connect tool 49G018901 or equivalent between throttle sensor and wiring harness.
d. Turn ignition system to On position.
e. Ensure throttle valve is fully closed.
f. Measure and record voltage of red wire.
g. Change volt meter connector to blue wire.
h. Loosen throttle sensor mounting screws.
i. Turn throttle sensor until blue wire voltage is equal to red wire voltage times .08 to red wire voltage times .12.
j. Tighten throttle sensor mounting screws and ensure blue wire voltage is as described.
k. Hold throttle valve fully open.
l. Ensure blue wire voltage is equal to red wire voltage times .78 to red wire voltage times .94.
m. If blue wire voltage is not as described, replace throttle sensor.
n. Turn ignition switch off.
o. Disconnect tool and reconnect throttle sensor connector.
p. Disconnect negative battery terminal and depress brake pedal for at least 5 seconds to eliminate control unit malfunction memory.