Description of On-Board Diagnostics
Description of On Board DiagnosticsEFI Warning Lamp (Instrument panel) An EFI warning symbol incorporated into the instrument panel will illuminate when the ECU detects that it cannot maintain correct air/fuel ratio due to a fault in one of the following fuel injection system components:
- Air flow sensor
- Oxygen/Lambda sensor
- Coolant/Water temperature sensor
- Throttle Position/Potentiometer
The symbol will illuminate on initial turn of the ignition key as part of the bulb check feature, and will go out after a few seconds.
If the symbol illuminates when the engine is idling or the vehicle is being driven, it indicates a failure of one of the four functions. The light will continue to come on until fault is corrected. There is no reset procedure.
Testing
To test and diagnose faults use:
- Lucas Hand Held Tester and follow Lucas Operating Instruction Manual.
or
- Follow the test procedures under Tests Using Multimeter for each of the functions to determine the problem. Component Tests and General Diagnostics
Which ever instrument is used to diagnose the problem, the following Preliminary Checks must be carried out first.
A. Fuse 18 - in main fuse panel - is intact.
B. Inertia fuel shut off switch is not tripped.
C. Check for ample fuel in tank.
D. Battery condition - fully charged.
E. Check air inlet system for possible leaks into the inlet manifold.
F. Electrical Connections - dry, clean and secure.
Only when the checks have been carried out, should circuit diagnosis begin.
Should one of the functions fail, the vehicle can still be driven due to a limp home feature incorporated into the fuel injection system. However, the vehicle should be driven with care and the cause rectified.