The PCM/ECM monitors the HO2S(B1/S1) transition frequency for predetermined time. During the monitoring period, the PCM/ECM calculates transition times that the front HO2S switches from rich to lean and from lean to rich. With this information, an average frequency for all switches can be determined. The PCM/ECM sets DTC P0133 when the average frequency is too slow.
The PCM/ECM monitors front oxygen sensor amplitude level and compares it to predetermined minimum amplitude value which could increase emission or disturb lambda control by the effect of aging on the oxygen sensor. The PCM/ECM sets DTC P0133 when the amplitude of oxygen sensor is equal to or less than minimum amplitude threshold.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Check Lambda control regulation frequency | 1. Leak in intake or exhaust system 2. Poor connection or damaged harness 3. HO2S contamination |
Enable Conditions |
•
Coolant temperature >73℃(163℉)
•
550℃(1022℉)< Catalyst temperature model <850℃(1562℉)
•
Vehicle speed >3mph
•
1300< Engine speed(rpm) <3200rpm
•
0.3g/rev.< MAF <0.8g/rev.
•
Canister load <0.5
•
Lambda control active
•
Stable driving condition
•
No opening/closing of canister purge valve
•
70kPa(700hPa)< Ambient pressure
•
No relevant failure
•
11V< Battery voltage <16V | |
Threshold Value |
•
Average Ratio between measured and maximum allowed frequency >1 | |
Diagnostic Time |
•
50 lambda controller cycles | |
Mil On Condition |
•
2 Driving Cycles |
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Check HO2S Signal Amplitude | 1. Leak in intake or exhaust system 2. Poor connection or damaged harness 3. HO2S contamination |
Enable Conditions |
•
see catalyst diagnosis(P0420) activation condition
•
No relevant failure
•
11V < Battery voltage < 16V | |
Threshold Value |
•
Integral ( Lambda signal amplitude measured / Lambda signal amplitude of a slow sensor ) > 1.0 | |
Diagnostic Time |
•
25 lambda controller cycle | |
Mil On Condition |
•
2 Driving Cycles |
