Monitor Description
The ECM monitors the intake air amount during idling, and the ignition timing.
When the engine coolant temperature is -10°C (14°F) or higher, and less than 50°C (122°F), the ECM calculates the idling intake air amount for 10 seconds, beginning 3 seconds after the engine starts.
When the accumulated amount is below the threshold, the ECM interprets this as a malfunction in the Idle Speed Control (ISC) system at cold start.
The ECM also monitors the ignition timing at cold start and determines it to be incorrect when it is advanced to the same value as a warm engine for 5 seconds or more of the 10 second monitoring period.
Example:
P050A is detected when all conditions below are met (2 trip detection logic).
- The engine coolant temperature is -10°C (14°F) or higher, and less than 50°C (122°F) when the engine starts.
- The engine idles for 13 seconds after engine start.
- The accumulated intake air amount is below the threshold.
The ECM stores the DTC and illuminates the MIL 13 seconds after the engine is next started.
When the cable is disconnected from the negative battery terminal during inspection or repairs, the ISC learned values are cleared. ISC learning must be performed by warming up the engine and idling for 5 minutes with the engine coolant temperature at 75°C (167°F) or higher because DTCs cannot be detected with the ISC learned values cleared.