jimvw

driving home tonight these codes popped up. ran fine, coolant temp is 196, outside temp is 6 degrees. I'm thinking corroded connectors?? maybe able to take a peek in the morning. should be about 10 above (?)

Oldblue

Possible causes P1174
Clogged Fuel Injectors
Faulty Oxygen sensor
Ignition problem
Fuel injection problem
Engine mechanical condition

Possible causes P1516
Faulty Throttle Actuator Control (TAC) module
Throttle Actuator Control (TAC) module harness is open or shorted
Throttle Actuator Control (TAC) module circuit poor electrical connection
Check Throttle Actuator Control (TAC) module connector for water
Binding or bent throttle plate-failed throttle body

Check the wiring harnesses for damaged connectors bent pins, corrosion.

donbrew

P1516 inhibits P1174 from running. So the throttle is the problem.
A low voltage condition may set P1516.
I would start with battery voltage then inspect the throttle harness connector.
Look at the butterfly, these are bad:
is it not in the rest position
is it binding
is it moving freely without resistance
is it filthy

Oldblue

And remember, do not move that throttle body butterfly plate manually! The plastic gears will strip and there’s no fixing that! Just replace the throttle body!
Perhaps hellshotrod has one he can send you, send him a PM

jimvw

good to know! I' ll see what I can see. Battery was installed 7 months ago (from the receipt) only 7 degrees out so I only checked the electrical connector, nothing bent but I did spray it down with contact cleaner. more when it warms up outside. seems intermittant so I would gues electrical.

Oldblue

A dirty throttle body can present as intermittent in this cold.

jimvw

a guy at work had the same issue, only a bit worse on his mom's caddy. it would only act up when it got below 30 degrees. he ended up replacing the throttle body.

donbrew

The grease in the works can get too stiff in the cold.

Oldblue

And that grease after all these years can get dried out and clumpy!

jimvw

i have seen videos mentioning a relearn sequence when the throttle body is replaced. is that something that can be done 'backyard mechanic' style or does it need a trip to the dealership?