With TBI

Fig. 076 Chart - Code 21 Throttle Position Sensor:

Fig. 077 - Wiring Diagram for Code 21 Throttle Position Sensor. VIN 0, VIN 2, VIN R, VIN U:

CODE 21,

TPS (SIGNAL VOLTAGE HIGH)

1.8L "J" SERIES

2.5L "A, X, & N" SERIES

FUEL INJECTION (TBI)
The Throttle Position Sensor (TPS) provide a voltage signal that changes relative to the throttle valve. Signal voltage vary from less than 1.25 volts at idle to 4.5 volts at wide open throttle and is non-adjustable.
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. TPS signal voltage is greater than 2.5 volts for 2 seconds
b. Engine speed less than 1600 RPM. This is the purpose for placing shift lever in drive (A-T trans.).
c. MAP is less than 60 kPa (9 psi) of equal to a no load condition.
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.