Checking the Basics

The logic module or SMEC has been programmed to monitor several different circuits of the fuel injection system in order to provide a self-diagnosis function. In conjunction with the self-diagnosis function, a power loss/check engine lamp is wired into the system to indicate a failure in the monitored circuits. The power loss/check engine lamp is illuminated for 3 seconds whenever the engine is started as a ``bulb test.'' However, if the logic module or SMEC detects a malfunction in one of the monitored circuits the power loss/check engine lamp will be illuminated and will remain on as long as the ignition key remains in the on position. Illumination of the power loss/check engine lamp indicates that the system has entered the ``limp-in'' mode and signals an immediate need for system service.
If vehicle performance or the power loss/check engine lamp indicate fuel injection system malfunctions, certain procedures should be followed. Prior to suspecting the fuel injection service as the cause for complaints, ensure that the engine and all related systems are in proper operating condition. After checking related systems, inspect fuel injection components and connecting harnesses as outlined in ``Visual Inspection,'' repair system as indicated, the road test vehicle to check system operation. If service performed during visual inspection does not correct observed malfunctions, or if power loss lamp remains illuminated, refer to ``On-Board Diagnosis'' to call up fault codes stored in the logic module or SMEC memory and correct as needed.