Trouble Codes and Reduced Power
 

I'll preface this post with the fact that we had VERY heavy rain last night, which I drove a total of about 70mi through. There was standing water, but it was on the highway and nothing that I would call major. Hit a couple times hard enough to plow water up to the roof line.

This morning, I start the car and the ABS/TC lights turn on. Drove the car about 10mi and stopped at a gas station. Restarted car and those lights went off and were replaced with a check engine light. Car seemed to run fine. Went out for lunch this afternoon and monitored the car in real time with torque app. Got code "U0073 - Network" after scanning. Reset this code while I had lunch. Restarted car and it was cleared and did not come back in my 15mi drive back to work. However, the car had a serious lack of power and I can press the gas pedal about an inch or so in before it registers RPM in both the mechanical gauge in the car and in Torque. Still no code. I suspect it will come back.

Quick search (just got back and will need to do more research) indicated the "U0073" code could be related to the Canbus 2 network. I am not familiar with this system yet, the symptoms, cause, or fix.

Due to the brake lights, I figured it may be related to a brake hanging up or the ebrake hanging. In neutral, it rolls perfectly free and there is no extra deceleration from coasting.

That's what I have so far. Any thoughts?

EDIT: A friend reminded me that the torque app can cause some canbus issues possibly depending on timing of starting/stopping the car and the app. Could be related to the code. There are still reduced power issues.

By brake lights, I take it that you mean the ABS/TC light that first appeared on the dash. I think that if the sensors get really wet and then dry it can possibly cause the ABS system to freak out a little and thus the ABS/TC system will shut off to prevent further problems related to that system.

The Canbus network issue COULD be related to your OBD2 reader. How about you disconnect the battery and the ECU reset. Do not reconnect the OBD2 reader, and just drive casually for a bit to see if anything comes up again.

I cleared the code already and it hasn't come back yet as mentioned in the post. The reduced power is the only thing that seems to be sticking around. I'll see if it's the same way again on my drive home. Going to check the air filter tonight and lift the car up and check it out. Could be something simple after hitting all that water. Although, if it were, I would expect that a reduced power issue would have been going on the whole time...not immediately after I cleared the code. Which is odd.

There are several threads on this. It's caused by the Torque app. If Torque is running when you start the car, the ECU gets confused, throws the U0073 code and puts the car into limp mode. You'll get the engine and traction lights and your air conditioner and cruise control will stop working.

The fix is easy. Just make sure that Torque is NOT RUNNING when you start the car. Even if you just stop for gas, exit Torque before starting the car again. You can exit Torque easily without turning off your phone by hitting the Android "back" button twice and selecting "OK" when asked if you really want to exit Torque.

If you drive with the car in limp mode (drive it without clearing the code first), the car will still be sluggish after you reset the code. That will clear up after a couple of restarts. The computer has to relearn. If you happen to notice that the check engine light has come on and reset the code before you take off in it, it will not be sluggish after you clear the code.

Also, it has been suggested that your OBDII connector plays a part. It doesn't. You can use the most expensive adapter or the cheapest piece of crap and still get the code if Torque is running when you start the car. It's the app, not the adapter.

You can also use the Torque app to clear the code. That's what I do.

Its annoying, so I stopped using Torque. Now I have a Scanguage 2 and no codes anymore. It doesn't look "cool" but can read Oil Temp/IAT/Coolant Temp/AFR.