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:
Description
In order to make normal activation of airbag system, SRSCM
detects DTC(s) for the Occupant Classification System (OCS). If the seat
is occupied, OCS detects passenger presences status and send signal to
SRSCM via CAN.
SRSCM recognizes the signal as 2(two) different
classifications; that is, 1(Empty or small occupant with child restraint
system), 2(Occupied with large occupant and small occupant)...
R..