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...
Inspection
[Measuring Resistance]
1.
Disconnect the cruise control switch connector from the control switch.
2.
Measure resistance between terminals on the control switch when each function switch is ON (switch is depressed).
Function switchTerminalResistanceSET -3 - 5550?±5%RES +3 - 5880?±5%CANCEL3 - 5330?±5%CRUISE3 - 51...