A malfunction is detected by using a checksum technique for verifying data. Digital data is composed of zeros and ones. A checksum is the total of all ones in a string of data. By comparing the checksum value with a stored value, a malfunction can be detected. During normal operation the microcontroller is monitored when the following test conditions have been fulfiled if there is overrun :
① No start present
② Accelerator pedal not actuated
③ Cruise control is not active
④ No increasing external fuel quantity command
The ECM will set a code if an error is detected in the ECM’s microcontroller malfunction during two driving cycles.
DTC NO. | Detecting Condition | Possible Cause |
C 022 C 023 C 024 C 025 | ● C 022 Error is recognized if the microcontroller is reported finally defective(Rcovery (new program start) occurred) ● C 023 Error is recognized if the injector is energzied when the engine speed is above the engine speed 2050 rpm and APS is 0 % with the range of fuel cut ● C 024 Error is recognized if the engine speed is not drop below 500 rpm within 1.5 sec. after turningthe ignition switch off (Watchdog after run test) ● C 025 Gate array communication error ● Engine Condition : IG ON (C022,C023,C025) IG OFF(C024) ● Fuel Limit : NO (C022,C023,C025) YES (C024) ● Fuel Cut : YES (C022,C023,C025) ● EGR OFF : NO ● MIL : NO ● LIMP HOME MODE Engine speed is not start in case of the detecting condition C022 | ECM |
