Originally Posted by btophek
So what does LDC mean and what does HDC mean?
I know this is an old thread, but if anyone still watching, LDC/HDC =
Light Duty Cycle (Vin Z), easily determined by checking if there are one or two O2 sensors (LDC has 1).
Heavy Duty Cycle (Vin 5), has 2 O2 sensors.
I checked this against my service manual to verify the O2 sensors.