On-Board Diagnostics

ON-BOARD DIAGNOSTICS
- The recording condition of diagnostic trouble code.
After the ECM first detects a malfunction, a diagnostic trouble code is recorded when be engine is restarted and the same malfunction is re-detected. (Malfunction is detected in driving cycle). However, for fuel system rich/lean misfiring, a diagnostic trouble code is recorded on the first detection of the malfunction.
- The erasing condition of diagnostic trouble code.
After recording the diagnostic trouble code, if the ECM does not re-detect the malfunction for 40 driving cycles, the diagnostic trouble code will be erased from the ECM memory. However, for fuel system rich/lean or misfiring, the diagnostic trouble code will be erased under the following conditions.
- When driving conditions (engine speed, engine coolant temperature, etc.) are similar to those when the malfunction was first recorded.
- When the ECM does not re-detect the malfunction for 80 driving cycles.

NOTE:
1. A "driving cycle" consists of the engine start, vehicle operation beyond the beginning of closed loop operation.