Signal Period For Oxygen Sensor Ageing, Bank 1 - Above/Below Limit

P0133

Signal Period for Oxygen Sensor Ageing, Bank 1 - Above/Below Limit

Function
The diagnosis of "oxygen sensor ageing" helps to identify oxygen sensors ahead of TWC that lead to emission limits being exceeded because of ageing.
During the diagnosis of oxygen sensor ageing, the DME control module monitors the period (oscillating frequency) of the sensor signal.
With an old sensor, the duration of the period is too long, i.e. it is more difficult for the sensor to diffuse oxygen into the exhaust gas. Reasons for this could be frequent driving in the lower load range (city driving, short distances, etc.) or a contaminated sensor.

Diagnosis conditions

P0133 - P0153:

Diagnosis Procedure







1 Road test vehicle or perform short test.
1. Erase the fault memory.
2. Heat the oxygen sensors (road test car under load or run engine for 10 minutes without load at high rpm).
3. Road test vehicle or perform short test, ensuring that the diagnosis conditions are reached.
4. Read out the fault memory.

2 Read out sensor-signal period, banks 1 and 2.
Read out period with scan tool in Mode 5 or with Porsche System Tester 2.

NOTE: Read out period counter too when using the Porsche System Tester 2. The counter must read 16, only then is the period reading reliable.

Period display: less then 2.3 seconds (Boxster) or
less then 3 seconds (996).

NOTE: For a new sensor, this value is approx. 1.0 second.