Hyundai Sonata LF: Engine Control System / Injector Troubleshooting
The three waveforms below are taken from the #1 and #4
injectors. The top waveform is from the high side (feed side) of the #1
and #4 injectors, while the middle waveform is from the low side (ground
side) of the #1 injector and the bottom waveform is from the low side
of the #4 injector.
The middle waveform is the same as the top waveform because
there is no ground for the circuit. With no current flowing in the
circuit, the #1 injector is not energized and fuel does not flow.
The bottom waveform shows that ground is supplied and there
is a voltage drop across the #4 injector. With current flowing in the
circuit, the #4 injector is energized and fuel flows.

Other information:
Inspection
1.
Connect the GDS on the Data Link Connector (DLC).
2.
Measure the output voltage of the MAPS at idle and IG ON.
Specification: Refer to "Specification"
Removal
1.
Turn the ignition switch OFF and disconnect the battery negative (-) cable...
System Block Diagram
Component Parts And Function Outline
Component partFunctionVehicle-speed sensor, ESP/ABS Control ModuleConverts vehicle speed to pulse.ECMReceives signals from sensor and control switches.Cruise control indicatorIlluminate when CRUISE main switch is ON (Built into cluster)Cruise Control switchesCRUISE switchSwitch for automatic speed control power supply...