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:
Replacement
1.
Turn the ignition switch OFF and disconnect the negative (-) battery cable.
2.
Lift the vehicle.
3.
Remove the rear-left wheel & tire and house cover.
4.
Disconnect the canister close valve connector (A).
5.
Disconnect the vapor hose (B)...
Warning Lamp Activation
Warning Lamp Behavior after Ignition On
As soon as the operating voltage is applied to the SRSCM
ignition input, the SRSCM activates the warning lamp for a LED lamp
check.
The lamp shall turn on for 6 seconds during the initialization phase and be turned off afterward...