| Case 1 |
DTC Strategy |
- Response rate check at entry in fuel cut-off (Rich-to-Lean)
|
- Leak in intake or exhaust system
- Faulty fuel system
- Front and rear HO2S connections reversed
- Poor connection or damaged harness
- HO2S contamination
|
| Enable Conditions |
- Downstream O2 sensor operative readiness is detected
- Downstream O2 sensor internal resistance is smaller than 3000Ω
- Catalyst temperature (model) is greater than 200°C (392°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 of sensor signal gradient is lower than 1500mV/sec.
- Signal gradient from 0.6V to 0.3V at entry in fuel cut-off is out of range
|
| Case 2 |
DTC Strategy |
- Response rate check after leaving fuel cut-off (Lean-to-Rich)
|
| Enable Conditions |
- 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 3000°C (572°F)
- O2 sensor internal resistance is smaller than 3000Ω
- Battery voltage is between 11V and 16V
|
| Threshold Value |
- Downstream O2S voltage is lower than 1500mV/sec.
- Signal gradient from 0.3V to 0.6V after leaving in fuel cut off is out of range
|
| Diagnostic Time |
- 3 valid fuel cut-off phases
|
| MIL On Condition |
|