Differences between the DTCs mode 3 and DTCs mode 7 in CAN
What are the differences between the DTCs mode 3 and mode 7 in CAN?
In SAEJ1979 The mode 7 sais: The purpose of this service is to enable the external test equipment to obtain “pending” diagnostic trouble codes detected during current or last completed driving cycle.
The mode 3 sais: The purpose of this service is to enable the external test equipment to obtain “confirmed” emission-related DTCs.
But I don´t undestand this. What are the diferences between "pending" DTCs and "confirmed" DTCs?
The PCM may set a pending trouble code the very first time a problem is detected. It might not set a confirmed trouble code (and light the MIL) until the same problem is observed repeatedly so the engine controller is quite certain that the problem exists.
Originally Posted by proyectanteATE
Thanks Joe for the information!!