Diagnostic warning lamp illumination conditions (while driving)

I - FAULTS CAUSING THE ONBOARD DIAGNOSTIC WARNING LAMP TO ILLUMINATE

1 - Electrical fault

Lamp illuminates steadily after several consecutive fault detections (depending on the component).

2 - Misfire rate damaging the catalytic converter

Lamp illuminates immediately and flashes.

3 - Catalytic converter, oxygen sensor, polluting misfire faults

Lamp illuminates steadily after three consecutive fault detections.

The catalytic converter and upstream oxygen sensor diagnostics are sequential; they take place:

• once per drive cycle (each test lasts a few seconds),
• only under certain specific driving conditions.

Under certain driving conditions (for example, in a traffic jam), some functions may not be diagnosed.

II - ONBOARD DIAGNOSTIC (OBD) WARNING LAMP MANAGEMENT

1 - Lamp illumination

If the same OBD fault is detected during three consecutive drive cycles, or an electrical fault is detected.

2 - Lamp flashing

If misfires are detected that cause damage to the catalytic converter.

3 - Lamp going out

If the OBD fault does not reappear during three consecutive drive cycles, the lamp goes out and the fault is stored in the injection ECU.

To clear the fault stored in the ECU without the diagnostic tool, no fault must be detected during 40 consecutive drive cycles.

The fault may not be detected again due to:

• the intermittent nature of the fault,
• the customer's driving pattern, as the vehicle is not always driven under the fault detection conditions.