DDEC III/IV Single ECM Troubleshooting – Section 21.2 SAE J1587 Equivalent Code for Flash Code 21

Section 21.2
SAE J1587 Equivalent Code for Flash Code 21

The SAE J1587 equivalent code for Flash Code 21 is p 091/3, TPS circuit high.‪

Section 21.2.1
General Throttle Information (Limiting Speed Governor)

The correct TPS counts for DDEC III engines at idle should be 64 - 205 counts.‪

1. Typical DDEC III foot pedals today, at idle, provide 102 - 205 counts.
2. DDEC II foot pedals can be used on DDEC III engines. The counts from the DDEC II style pedal may go as low as 64 counts at idle, but this is still acceptable.
3. The DDEC system will log a TPS low volt code (PID 091, FMI 4, Flash Code 22) if the TPS counts go below 48.
4. The DDEC system will log a TPS high volt code (PID 091, FMI 3, Flash Code 21) if the TPS counts go above 968 counts.
5. In order to go from 0% to 100% throttle, the counts have to increase 546 above the idle count, or 100 counts, whichever is greater.
6. If an idle validation switch (IVS) is configured, to go from 0% to 100% throttle, the counts have to increase 546 above the counts at which the IVS opens or 100 counts, whichever is greater.
7. If 0% throttle is attained with the foot off the pedal, and if 100% throttle is attained with the pedal to the floor, then the pedal should not be considered a factor for low power complaints.