Test Groups WBMXV02.8M52 & WBMXV02.8Z35
General Description - Fuel system monitoring includes lambda controller restriction against limits for rich and lean and permanent deviation from mean position.
Monitoring Structure - If fuel system is suddenly hard disturbed (for example: by a leaky injection valve) and therefore lambda controller reaches restriction (lean limit), a timer is started. Timer is incriminated as long as controller remains at limit. If timer exceeds a predetermined value, a fault for short trim will be detected and stored. For permanent deviation from mean position, there are additional lean and rich thresholds. If accumulated time (sum of all excesses for rich and lean) is greater than a fixed limit during a defined period, a fault for long term trim will be detected and stored.