If the lambda controller reaches the maximum or minimum threshold, then feedback control is no longer possible and emissions will be increased. The PCM/ECM sets DTC P2188 if no proportional post catalyst fuel trim adaptation occurs for a defined time after the lambda controller has reached its minimum threshold at idle.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Monitoring deviation of long term fuel trim control in Idle | 1. Air restriction in intake or exhaust system 2. Front HO2S or MAFS contamination 3. Faulty sensor signals 4. EVAP system 5. Fuel system |
Enable Conditions |
•
No relevant failure
•
Lambda adaptation active | |
Threshold Value |
•
Idle long term fuel trim has reached Max. Limit for more than 20 sec. within 90 sec < -0.005g/rev( -2.5mg/stk) | |
Diagnostic Time |
•
90 sec. | |
MIL On Condition |
•
2 Driving Cycles |
