Background, it was a warm day (80F/27C) during my afternoon commute. I had recently exited the highway and was nearly finished with the final stretch to my home on a side street. Suddenly, the CEL and VSA light up and the car goes into limp mode. After parking it, I checked it for codes. In addition some EVAP and O2 sensor codes that I am aware of, it threw U0107 - which is a loss of communication with the throttle control.

Per forum search instructions, I checked battery voltage and oil level; both were fine. The one visible clue I have is a huge sneeze that the coolant overflow reservoir took over the engine bay. Since I did not see any engine overheat lights on, this was unexpected. Could the coolant have shorted out some of the plugs and caused the code?

If this is the case, should I use vinegar to clean out the plugs?

 

Anyone?

 

No idea if the coolant could have caused the connections to short out....but I would for sure be replacing the overflow cap. You can pick them up cheaply from your local Honda dealer.

 

Check all the coolant hoses for cracks and loose connections and is the coolant low in the reservoir?

 

Your radiator cap's spring inside might have failed briefly and the coolant went into and overfilled the overflow tank. Then coolant blew out of the overflow tank. That's what it looks like to me, according to the direction of the coolant spray. I suggest you replace the radiator cap, and put 2 spring clamps on the tube for the overflow tank. That small tube isn't pressurized but I've found that it leaks coolant if you don't clamp it down.

 

I'd use CRC Electronic Cleaner to clean the contacts between the sensors and throttle body connection. It's not a bad idea to clean them on occasion anyways. I clean most of mine as well as the contacts in the coil packs every once in a while.

I don't think a small amount of coolant like that would short something out. Most of the sensor connections are pretty tight. I've even pressure washed my engine bay without any shorts (not good practice though. I don't recommend doing that).

Check the connection of your coolant hoses to the thermostat housing and radiator. And like others have said, consider getting a new radiator cap. If you do, get a good quality one.

 

+1 check rad cap. It's probably missing the pressure spring. Without pressure coolant boils.

 

I will definitely look into the radiator cap thing, but I have a new theory to test. Closer inspection of the engine bay revealed a tear in the air flow hose. Wear in the hose is accelerated by excessive movement of the engine. It would seem that all roads lead back to the motor mounts. I am partway through that job and will put it to the test once complete.

 

 

Update:

A few months ago - just a few days after finishing with the engine mounts and air intake tubing replacements, the engine stalled on the highway. I had a trusted mechanic diagnose the problem. His conclusion was that the U0107 code was a result of the Throttle Actuator Control Module malfunctioning. Additionally, he suspected that its problems were also causing malfunctions with other systems: Evap and O2 sensor readings.

After discussing the matter, he went and electronically reset the TAC module. To replace it would run ~800 USD for parts alone; labor entails digging deep beneath the dashboard to reach it. I have not had any malfunctions since the reset, but I really don't want to hold onto the TL long enough to find out. Since I have had to pull the battery a few times since then for other work, I don't know if the engine has logged enough to come back up with any more related errors. I plan to replace the TL once I have a better idea of my budget into next year. Given the immense bill of work I have had to put into the TL in the <7000 miles that I have owned it, I am sour to buying another Honda product again in the near future and I can see why the last owner did not want it anymore.

 

do you know how the mechanic reset your TAC module? I've done all the voltage and continuity testing on the TAC module & PCM that was listed in the manufacturer service manual for the U0107 DTC and everything came out normal. even bought a (used) TAC module and tried it but it didn't help. since all the tests came out normal I assumed the only other thing left that could be the problem is the PCM but i can't afford to get another PCM ESP if it ends up not fixing the issue!
did you happen to see the mechanic do the TAC module reset or did they happen to tell you anything about the procedure? I'm at my wit's end with this car and would love to just sell it but i know i wouldn't get anything out of it selling it the way it is now!! plz keep me posted in the future as well if you don't mind bc this DTC is uncommon and although i feel for you I'm still somewhat relieved to see I'm not the only person who's dealt with this on a similar Acura.