DTC 21

Code 21 - Throttle Position Sensor Circuit (Voltage High):

Wiring Diagram For Code 21 - Throttle Position Sensor (Signal Voltage High):

CODE 21 - THROTTLE POSITION SENSOR (SIGNAL VOLTAGE HIGH)

Circuit Description:

The throttle position sensor (TPS) provides a voltage signal that changes relative to the throttle valve. Signal voltage will vary from less than 1.25 volts at idle to about 4.5 volts at wide open throttle (WOT).

The TPS signal is one of the most important inputs used by the ECM for fuel control and for many of the ECM controlled outputs.

Code 21 will set if all the conditions below are met:

^ TPS signal voltage is greater than 3.5 volts for 5 seconds.
^ Engine speedless than 1200 RPM.
^ MAP is less than 30 kPa (4.5 psi) vacuum or equal to a no load condition.


Test Description:

1. Confirms Code 21 and that fault is present.

2. Simulates Code 22: If the ECM recognizes the low signal voltage and sets Code 22, the ECM and wiring are OK.