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Throttle position sensor

Throttle position sensor



The position sensor consists of a potentiometer connected to the throttle spindle.

The sensor is powered with 5 V from control module pin 42 and is grounded from control module pin 67. The voltage from the sensor is connected to control module pin 45 and is proportional to the accelerator depression. At idling speed the voltage is approx 0.5 V and with wide open throttle approx. 4.5 V.

The control module uses the voltage from the sensor to identify idling, partly open throttle and wide open throttle. At idling speed, the control module uses a special ignition control matrix to govern the idling speed.

Closed loop is disengaged at wide open throttle.

Fuel injection is shut off if the throttle is wide open when the starter motor is cranking.

As the accelerator is depressed, acceleration enrichment will take place and when the accelerator is released, deceleration "lean-out". The requested boost pressure is also dependent on the throttle position. If there is a sensor malfunction or break in the circuit, the control module will set wide open throttle as a substitute value.

Diagnosis


• If the sensor voltage is too low, diagnostic trouble code P0122 will be generated

• If the sensor voltage is too high, diagnostic trouble code P0123 will be generated


System reaction to a fault


• Fuel adaptation blocked.

• Purging blocked.


Throttle position signal

The control module transmits the throttle position signal from pin 57. This is a PWM signal at 100 Hz that always has a pulse ratio of 9 % at idling speed (approx. 1.2 V) and approx. 90 % at wide open throttle (approx. 12 V).

With the ignition on and the engine stationary, the pulse ratio will be 2-7 % and represents the engine coolant temperature.

The throttle position signal and temperature signal are used by the automatic transmission control module.

Diagnosis


• No diagnosis. However, TCM will generate a diagnostic trouble code and turn on CHECK GEARBOX if there is a break or short circuit.