911 Turbo Cabriolet (996) F6-3.6L Turbo (2004)
Oxygen Sensor: Testing and Inspection
Diagnosis Of Universal Lambda Sensor - UEGO
Diagnosis Of Universal Lambda Sensor - UEGO (911 Turbo)
General Description
Offset
Incorrect lambda measurement due to shunting effects. Diagnosis: Lambda-offset of downstream control exceeds threshold.
Heater Coupling
Low impedance coupling between heater and sensor can cause lambda modulations with the heater pulse rate.
Dynamics - Slow Response
Due to aging the sensor dynamics can decrease. Diagnosis: Comparison of measured and estimated (model-based) lambda-error caused by artificial
lambda modulation.
Plausibility
a. Power Stage - Diagnosis:
Output Voltage of the Power Stage will be switched to >= 4.775 Volts, if a hardware malfunction has been detected by IC.
b. UEGO (Universal Lambda Sensor = LSU) not active:
Diagnosis: Lambda(LSU) is close to 1.0, but downstream sensor indicates lean or rich mixture
c. Sensor current high (Lambda LSU lean):
Lambda(LSU) [>] 1.2 while downstream sensor indicates rich mixture
d. Sensor current low (Lambda LSU rich):
Lambda(LSU) [<] 0.8 while downstream sensor indicates lean mixture
Oxygen Sensor Output Voltage Characteristic Diagram
Monitoring Overview Diagram