DDEC TROUBLESHOOTING
21.1 DESCRIPTION OF FLASH CODE 21
Flash Code 21 indicates that the Throttle Position Sensor (TPS), see Figure 21-1, input to the
ECM has exceeded 95% (normally >4.75 volts) of the sensor supply voltage.
This diagnostic condition is typically:
Open sensor return circuit
Sensor signal circuit is shorted to the sensor +5 volt supply
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
21-3
