Conditions for performing diagnostics (while driving)

I - ENTRY CONDITIONS FOR DIAGNOSTICS

If, at ignition on and while driving, the air temperature read by the temperature sensor is not between -7.5 °C and 119.39 °C, or the coolant temperature read by the sensor is not between -7.5 °C and 119.39 °C, or the difference between 1046 mbar and the intake manifold pressure is greater than 273 mbar (altitude of approximately 2500 metres), then OBD diagnostics are not permitted until the next ignition on.

For the OBD system to operate correctly, there must be no electrical fault present on the injection system, even if the OBD warning lamp is not illuminated.

Oxygen sensor and catalytic converter diagnostics can never be performed at the same time.

While the catalytic converter and oxygen sensor diagnostics are running, the fuel vapour canister purge valve is closed and the adaptive values are frozen at their last value.

II - TEST SEQUENCE LOGIC

Before performing the tests, proceed in the following order:

• rectify all electrical faults,
• clear all faults,
• carry out all injection learning procedures,
• check the OBD system.

III - COMPLETE RESET OF THE ONBOARD DIAGNOSTIC (OBD) SYSTEM

To reset the OBD function, it is necessary to perform:

• clearing of stored faults,
• clearing of OBD faults,
• clearing of adaptive learning values.

IV - LEARNING PROCEDURES REQUIRED FOR ONBOARD DIAGNOSTICS (OBD)

Learned values must be reset when replacing:

• the injection ECU,
• the flywheel target wheel,
• the engine speed sensor.

1 - Flywheel target wheel learning

Perform two successive decelerations in third gear, from 4000 rpm down to engine re-engagement speed.

Engine re-engagement is the point where, during a deceleration with the foot off the pedal and injection cut off, the ECU re-enables injection.

2 - Fuel richness adaptive learning

To carry out this learning, drive the vehicle while keeping within the pressure ranges (Petrol Injection chapter, Mixture Control, page 17B-31).