| Case 1 |
Main Action |
- Response rate check at entry into fuel cut-off (Rich-to-Lean)
|
- Leakage in intake or exhaust system
- Faulty fuel system.
- Front and rear HO2S connections reversed.
- Poor connection or harness damage
- HO2S contamination
|
| Prerequisite Condition |
- Downstream O2 sensor operative readiness is detected.
- O2 sensor internal resistance is lower than or equal to 3000Ω.
- Catalyst temperature (model) is higher than 400°C (752°F).
- Downstream O2 sensor signal at entry into fuel cut-off is higher than 0.6V.
- Battery voltage is between 11V and 16V.
|
| Threshold value |
- Average signal gradient per second during diagnostic time is under 1000 mV.
|
| Diagnosis Time |
- 3 valid fuel cut-off phases
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| Case 2 |
Main Action |
- Response rate check after leaving fuel cut-off (Lean-to-Rich)
|
| Prerequisite Condition |
- Downstream O2 sensor operative readiness is detected.
- Mass air flow integral after leaving fuel cut-off is bigger than 100g.
- Catalyst temperature (model) is higher than 400°C (752°F).
- Exhaust gas temperature (model) at sensor location is higher than 400°C (752°F).
- O2 sensor internal resistance is lower than or equal to 3000Ω.
- Battery voltage is between 11V and 16V.
|
| Threshold value |
- Average signal gradient per second during diagnostic time is under 1500 mV.
|
| Diagnostic Time |
- 3 valid diagnostic cycles
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| MIL-On Condition |
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