Triangle of death, P3191. On again, off again

[GRINCAR]

Is it safe to drive my '02 with the triangle on the dash? I've tried to get rid of it, throttle body cleaned, MAF cleaned, battery seems good (13v, no load). What else can I do to try and get rid of it? BTW, '02 Prius, 183K mi. It runs good, cycles on and off normally (motor to battery, etc.). The code clears it self after sitting about a week w/ occasional starts, then I drive it for about 50-70 miles and the light comes back on...what gives? Any thoughts are appreciated.

[edthefox5]

Originally Posted by GRINCAR

Is it safe to drive my '02 with the triangle on the dash? I've tried to get rid of it, throttle body cleaned, MAF cleaned, battery seems good (13v, no load). What else can I do to try and get rid of it? BTW, '02 Prius, 183K mi. It runs good, cycles on and off normally (motor to battery, etc.). The code clears it self after sitting about a week w/ occasional starts, then I drive it for about 50-70 miles and the light comes back on...what gives? Any thoughts are appreciated.

Whats the 12 volt battery look like under load. Not running 14v I mean under load?
And how often have you changed the trans fluid please?

[seilerts]

A code will clear itself after 3 starts and offs, so long as an OBD trip is NOT completed.

Did you use MAF cleaner or TB/carb cleaner on the MAF?

It is interesting that this happens after 50 miles of driving. Is that 50 miles of driving on a single trip, or 50 miles worth of short trips? Does it happen while driving, or on a cold start?

There is a long laundry list of possible causes, like throttle motor/sensor, crank+cam position sensors, coolant temp sensor or lack of coolant (do you have your grill blocked?), fuel pump, MAF sensor (bad, not just dirty), ECM.

[GRINCAR]

Originally Posted by seilerts

A code will clear itself after 3 starts and offs, so long as an OBD trip is NOT completed.

Did you use MAF cleaner or TB/carb cleaner on the MAF?

It is interesting that this happens after 50 miles of driving. Is that 50 miles of driving on a single trip, or 50 miles worth of short trips? Does it happen while driving, or on a cold start?

There is a long laundry list of possible causes, like throttle motor/sensor, crank+cam position sensors, coolant temp sensor or lack of coolant (do you have your grill blocked?), fuel pump, MAF sensor (bad, not just dirty), ECM.

I used TB cleaner on the TB, I removed the MAF prior to squirting the TB cleaner, MAF cleaner on the MAF then I reinstalled it. They were short trips and the triangle and dagger through the car symbol have come up on "cold" (not cold weather) starts. I'll check the grill and radiator, I think they were pretty clean, I'll check anyway. There is coolant to the proper level in the reservoir and radiator neck, oil is fresh, plugs new. I put the scanner back on it today after mechanic tried to figure it out and no P3191, but the scanner shows a yellow light for the emission control system area (suggests that it won't pass a smog test.) But no DTC's now. I would like to try to fix this myself, check or fix everything I can before the dealer gets it. Also, today when I picked up the car from the mechanic the light did not come on right away, came on about five minutes later as I was driving away, car was running great but the lights (Triangle & dagger)were on. I went home and used the scan tool to clear the lights, they went off for about 30 seconds then came back on, car was still running, then it cycled off to battery, a little bit later it started up by itself like it should. More thoughts please.

[GRINCAR]

Originally Posted by edthefox5

Whats the 12 volt battery look like under load. Not running 14v I mean under load?
And how often have you changed the trans fluid please?

I had the trans fluid done I think about 40K ago, probably need to do it again. As for the battery, I'll go get it checked tomorrow and let you know what they say. The 14v for the battery was when the car was parked ignition off. I may be confused by what no load means. Thanks for advice.

[seilerts]

Originally Posted by GRINCAR

I used TB cleaner on the TB, I removed the MAF prior to squirting the TB cleaner, MAF cleaner on the MAF then I reinstalled it. ... More thoughts please.

Normally, you would remove the whole air intake in order to access the throttle body. I am inferring that you left the intake in place. Please provide more details of how you cleaned the TB. The usual procedure is to spray TB cleaner on a shop towel, use a rod of some sort to prop open the throttle plate, and carefully remove carbon buildup from the plate and the bore. A ridge of carbonized gunk will form in the bore underneath the throttle plate, which causes it to stick, and gives you P3191.

Another common emission-related failure is the HCAC valve. An OBD reader might not have the code for it (P1436).

Also, have you ever replaced the PCV?

[GRINCAR]

Originally Posted by seilerts

Normally, you would remove the whole air intake in order to access the throttle body. I am inferring that you left the intake in place. Please provide more details of how you cleaned the TB. The usual procedure is to spray TB cleaner on a shop towel, use a rod of some sort to prop open the throttle plate, and carefully remove carbon buildup from the plate and the bore. A ridge of carbonized gunk will form in the bore underneath the throttle plate, which causes it to stick, and gives you P3191.

Another common emission-related failure is the HCAC valve. An OBD reader might not have the code for it (P1436).

Also, have you ever replaced the PCV?

Took the intake stuff off to get to the throttle body & MAF. Removed the MAF assy. and cleaned the TB with TB cleaner and rags/paper towels, got in there with my fingers, cleaned both sides of the butterfly, the pivots and the throat real well. PCV valve don't know if its ever been replaced. HCAC valve sounds expensive is that something I can grease up so it will work again? thanks for your feedback.

[andyprius]

Originally Posted by GRINCAR

Took the intake stuff off to get to the throttle body & MAF. Removed the MAF assy. and cleaned the TB with TB cleaner and rags/paper towels, got in there with my fingers, cleaned both sides of the butterfly, the pivots and the throat real well. PCV valve don't know if its ever been replaced. HCAC valve sounds expensive is that something I can grease up so it will work again? thanks for your feedback.

Changing the PCV is pretty easy, just remove the wiring harness above and to left of head. It's a bit awkward but doable. That might cure the problem.