Throttle Position Sensor: Description and Operation

PURPOSE
With this signal, the PCM can determine precise throttle position under all operating conditions.

OPERATION
The Throttle Position sensor (TP) contains a potentiometer that is operated by the throttle blade shaft. As the throttle plate rotates, the TP sensor provides a variable 0 to 5-volt signal to PCM cavity 35. The voltage is directly proportional to throttle angle. When the throttle plate is at rest, the voltage is low. When the throttle is fully open, the voltage is high.

The TP sensor receives a 5-volt supply from PCM cavity 43. The sensor ground is provided by PCM cavity 51.

NAME OF CODE: No 5 Volts to TP Sensor

When Monitored:
Vehicle speed above 20 mph, MAP sensor vacuum above 3 in., and engine speed above 1500 rpm.

Set Condition:
TP sensor signal goes below 0.5 volts.

Possible Causes:
- Open 5 volt supply
- TP sensor failure

NAME OF CODE: Throttle Position Sensor Voltage High

When Monitored:
With the ignition ON.

Set Condition:
Throttle Position (TP) sensor voltage at Powertrain Control Module (PCM) cavity 35 goes above 4.5 volts for 0.704 seconds.

Possible Causes:
- Sensor signal circuit open
- Throttle position sensor failure
- Sensor ground circuit open

NAME OF CODE: Throttle Position Sensor Voltage Low

When Monitored:
With the ignition ON.

Set Condition:
The Throttle Position (TP) sensor voltage at Powertrain Control Module (PCM) cavity 35 goes below 0.2 volt for 0.704 seconds, or MPH is above 20, RPM is above 1500, and vacuum is below 2" with TP sensor voltage less than 0.5 volt for 0.704 seconds.

Possible Causes:
- Sensor signal circuit shorted to ground
- Throttle position sensor failure
- Loss of 5-volt supply