OK. Been off experimenting for the last month and a half. I return bearing food for thought.
When warm weather returned to the Pacific Northwest, I started getting frequent P011B faults.
Didn’t get any faults all winter, but now they’re almost non-stop, so figured I’d try some stuff (short of removing the bypass and plates) to see what happens.
This is a 2010 Tundra 5.7L with over 100,000 miles. No “reflash” or “Smart Stop” software update on this ECU – it’s the same as the day I drove it off the lot. I retained GeorgiaDave’s version of the bypass and kept blockoff plates installed. For review, I have experienced P011B faults with the original relay version and Paul Hewitt's version as well. This seems to me to be a Tundra component tolerance issue that, in my case at least, is brought on by warmer weather.
1. Replaced the coolant temperature sensor. Easy. But no change.
2. Replaced the MAF/IAT unit. Another easy one. Still no change.
3. Electrically shielded the bypass module and wiring by inserting it within large diameter copper braid, and grounded the shield at both ends. Thinking maybe there were some stray induced signals. Ha! No change. Like it wasn’t even there.
4. Then took the original coolant temperature sensor and mounted it to the engine so I could plug in the harness connector and cold start it that way, then stop the engine after 30 seconds or so (once the correlation check had been made) and move the connector back to the real coolant temp sensor. Coolant and air temps identical or within one degree at cold start. Did this every morning for 2 weeks. Still got fault code every 2 or three days. That means my suggestion earlier in this thread about having a bypass that modifies both Air temp and Coolant temp simultaneously would most likely not work.
I noticed something during all this, though. After a code reset, so long as the Scangauge reports readiness monitors NOT READY, the fault will usually not appear. Usually, because occasionally it will. That tells me one of the readiness monitors not set is suppressing the fault. But which one?
When I check the Scangauge after I park the Tundra for the night, and it reports readiness monitors READY, I can expect the fault to appear on the next morning’s cold start. I’m not disappointed.
The Scangauge does not indicate the state of individual readiness monitors. It only reports NOT READY if any of the monitors are not ready, or READY if all the monitors are ready.
I do not own a device that indicates the state of individual readiness monitors. Right now I’m wishing I did, so I could try to pin this down.
5. Then, on a hunch, I tried this: regardless of the state of the readiness monitors, when I cold-start the engine, I would start it, let it run for 2 or 3 seconds, then turn it off and remove the key to reset any ECU logic associated with key insertion, engine start/run, etc. Then re-insert the key and restart.
No faults evident. With all readiness monitors set. No faults.
Kept this up for the past 2 weeks with no fault codes ever.
Well now, seems I’m on to something, but I have no idea exactly what - Maybe some of you smart folks out there can offer some ideas.
Good or bad, if it’s been 6 or more hours since the engine has run and I keep cold-starting the Tundra this way, I stop getting the P011B fault.
Steve
P-1445 Valve stuck closed. I'm finally ready to fix this problem once and for all. I've thought about replacing the parts myself, but I'm worried that it'll just happen again eventually so I'm just going to install the bypass. During a cold start, I don't hear a loud vacuuming noise or jet engine sound as people have described with this problem, and my truck doesn't go into limp mode afterwards. My only question is this: Will I need to purchase and install the two block off plates?
