Lambda control activation monitoring: Description

To check the plausibility of the coolant temperature sensor output (TCO) prior to closed loop fuelling, a modeled value of TCO (TCO_SUB) and an after start timer are used.

After starting the engine a timer is incremented (the timer is disabled by certain engine states such as fuel cut). Once both TCO_SUB and timer are above closed loop thresholds then, assuming all other conditions are met (idle speed, fuel cut, engine load and intake air temperature conditions), TCO failure detection is enabled.

If the coolant temperature sensor output is not above a threshold to enable close loop control, the error 'Insufficient Coolant Temperature for Closed-Loop Control' is flagged.