| Case 1 |
Main Action |
- Monitor HO2S characteristic line shift - strong shift to rich
|
- Poor connection or damaged harness
- Faulty HO2S
- Restricted of fuel filter in fuel pump
- Faulty ECM
|
| Prerequisite Condition |
- Upstream O2 sensor operative readiness is detected
- Downstream O2 sensor operative readiness is detected
- Active test is not activated
- Catalyst purge after fuel cut off is not functioning
- Engine speed is faster than 600 RPM
- Mass air flow is lower than 83 g/sec.
- Exhaust gas temperature (model) is between 300°C (572°F) and 800°C (1472°F)
|
| Threshold Value |
- Upstream lambda (rich) is lower than 0.7 and Downstream O2 sensor signal voltage (lean) is lower than 0.05V
|
| Diagnosis Time |
|
| Case 2 |
Main Action |
- Monitor HO2S characteristic line shift - middle shift to rich
|
| Prerequisite Condition |
- Fuel cut off is not functioning.
- Full load is not active with accelerator pedal value 90% or lower.
- Catalyst overheating is not prevented with 960°C (1760°F).
- Battery voltage is between 10V and 16V
|
| Threshold Value |
- Lambda value is lower than 1.05 when its set point equals to 1.15.
|
| Diagnosis Time |
- 10 Seconds after lambda set point is shifted to corresponding side.
|
MIL On
Condition |
|