600hplt1sm

Hello, I tried to start the car this morning and it just turns over. Never really does try to fire. My scanmaster shows DTC 16, Ive done some research on here to find out what that code is, I drove the car wed night and everything was fine. I didnt drive it yesterday & now all of a sudden this. I do have fuel pressure and I have checked the fuses for the injectors and the ignition everything there seems to be ok. I guess i will check the connectors tomorrow but this setup is only about 850 miles old. If the connectors look ok Am I to assume the Opti is done.

<Puck>

DTC16 is usually the opti. It is some pulse code, I forget if its the low or high.

Injuneer

DTC 16 = loss of low resolution pulse signal from the Opti optical sensor. When this code sets, car won't start because the code shuts down the fuel system (pump and injectors).

Not unusual to find this as a "stored" (not active) code, and the ScanMaster doesn't differentiate between stored and active codes. Pull the "PCM BAT" fuse for 30 seconds to clear the code. Then try and start it and see if the code comes right back. If it does, it confirms the cause of no start.

If code continues, check the two harness connectors for the Opti. The one that plugs into the Opti and the gray one on the bracket on the passenger side of the intake manifold. Look for corrosion or damaged pins. If the connectors are OK, its pointing to the Opti.

600hplt1sm

Thanks Fred. I checked the one up by the intake & it looks ok. I will check the other one tomorrow when its light out. Ill reset the pcm and see if it throws the code again. I guess ill get the ac delco unit this time. In peoples opinion does that seem to be the best choice

600hplt1sm

well i checked the connections for corrosion and there is some present on the opti plug & i can see some down inside. I also went through with my volt meter and checked the harness and it shows 5 volts just like the gm service manual says, SO i guess my conclusion is either the corrision in the opti is causing the problem or the opti is bad. Is there anything i can do about the corrosion without having to remove the opti. If I have to remove it I should go ahead a put a new ac delco unit in there. The one I have is a used unit anyway. Is there any suggestions or should I just open up my wallet

Injuneer

The connector "tower" on the Opti is the real weak point. That's the seal that leaks most often. I suspect the blue-ish corrosion that people find is related in some way to the seal leaking and ozone from inside the unvented Opti corroding the terminals. Alternatively, a gassing battery can cause the blue-green corrosion when the sulfates from the battery cause the formation of copper sulfate on the pins. You don't want to spray anything wet on the Opti, because its likely to end up inside. Maybe a scrubbing with a toothbrush. If its copper sulfate, make a dry paste of baking soda and a couple drops of water. That will dissolve the corrosion. At least make sure you get all the corrosion off the harness connector pins, and make sure the pins are not damaged.

97 RedSS

I see this same DTC in datamaster and I usually clear it out and it goes away. Is this DTC supposed to cause the SES to illuminate? I will check my opti for corrosion also..

Thanks

Cody

Injuneer

I think the code sometimes sets when the PCM has a hard time finding the low res pulse on cold start. It isn't unusual to see it as a "stored" code. Does not seem turn on the SES light, but if it was an active code the engine wouldn't be running.

wrd1972

I get a fluke DTC16 from time to time. Opti is not old. I dunno.

600hplt1sm

Well I bought a new opti harness from EFI connection & plugged it in & the car fired right up. I did put a small amount of dielectric grease on the plug connections this time. Hopefully that will help some.