With PFI

Fig. 021 - Wiring Diagram for Code 21 Throttle Position Sensor (Signal Voltage High). VIN J:

CODE 21

TPS (SIGNAL VOLTAGE HIGH)

1.8l TURBO "J" SERIES

FUEL INJECTION (PORT)

The Throttle Position Sensor (TPS) provides a voltage signal that changes relative to the throttle valve. Signal voltage will vary from about .5 at idle to 4.5 volts at wide open throttle.
The TPS signal is one of the most important inputs used by the ECM for fuel control and for most of the ECM controlled outputs.

Code 21 will set if:
a. Engine is running
b. TPS signal voltage is greater than 2.5 volts for 8 seconds
c. Engine speed less than 1600 RPM. This is the purpose for placing shift lever in drive.
d. Code 33 or 34 not present at start-up
e. MAP is less than 70 kPa (10 psi) (no load condition)

Possible causes of Code 21:
a. Faulty TPS
b. Faulty Wiring or terminals
c. Faulty ECM

Fig. 020 - Chart - Code 21 Throttle Position Sensor (Signal Voltage High):

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.