An update . . . I took the 2006 Elantra into the dealer yesterday,
and the DTC was once again P0172. According to the Service Advisor,
the tech called Hyundai's techline, and they recommended replacing the
upstream O2 sensor, which was done. I don't believed they checked the
PCSV, as I suggested to them. Interestingly, they claim this is the
first time they've seen consecutive P0172 codes - which I find
interesting and doubtful. We'll see what happens - if the CEL comes
on again in 4 or 5 weeks, I may take the car to another dealer!
The dealer in this case does not allow customers in the service area.
This is a new "mega dealer" with Hyundai, Kia, Toyota, Scion,
Mitsubishi, Chrysler, VW, and Mazda franchises, and multiple dedicated
show rooms. Toyota and Scion, as well as VW, have their own dedicated
service areas, whereas all others are serviced in one giant service
area. It's a beautiful dealership covering many acres, and thousands
of cars in inventory, plus the customer waiting areas and restrooms
would make some upscale hotels proud, with flat screen plasma TVs
hanging from the walls, free Wi-Fi, free donuts and coffee, and a
plethora of other amenities. I would gladly exchange all of this
luxury for successful troubleshooting and repair the first time by a
tech when a problem occurs. OTOH, I understand how difficult it can
be to pinpoint problems in today's technically loaded vehicles.