Skip the auto shop - Our mechanics make house calls

Q: 5mph max in 40 miles & code U3107

asked by on

We have a 2014 Ram 3500 and it has a message saying 5mph max in X amount of miles we plugged in a code reader and it's throwing the code U3107. The nearest dealer is 100+ miles away on my way home it flashed off and about 50 miles later it came back. Is it driveable?

My car has 37895 miles.
My car has an automatic transmission.

A: Diagnostic Trouble Code U3107 refers to a f...

Diagnostic Trouble Code U3107 refers to a fault in the vehicle’s network communications system, which includes the controller area network (CAN) wiring bus and modules on the vehicle. Unless other warning lights are on and/or the check engine light is flashing (as opposed to "steady") you can drive the vehicle. A flashing check engine light often means the engine is misfiring and that is one circumstance in which you do need to stop the engine reasonably quickly.

There are some general causes that would set Code U3107 but to get to the root issue a CAN capable scanner has to be used that can get associated freeze frame data. U3107 can set if certain CAN module connections are faulty, if there is a short to ground, an open, or voltage is below specifications. If the battery is dead, modules will lose settings or locations thus setting this code. In that event, relearning, or "re-set" procedures require a factory scan tool or a professional level aftermarket scan tool. You might try erasing the code and see if it recurs. You have referred to limp mode in your question which raises the possibility of, for example, loss of communication between modules such as an engine controller or transmission controller. You can perform a quick check of the soundness of connections at each CAN module by checking for voltage at the module, a good ground, and finally the data line. If all three check out but the module is reported by the scan tool as not communicating, the module needs will typically be replaced. YourMechanic can dispatch a professional with the appropriate check engine light diagnostic tools to identify the root cause of Code U3107 and resolve the issue for you. Please let us know if we can assist you with such a mobile visit.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Mazda 6 reliability

While we are not permitted to endorse certain makes and models of vehicles, we can tell you there are several other websites that not only have customer reviews, but also list the common problems. Often you can find great information...

Q: Trailer brake not working

Hello. If the trailer brake system is not working, then it may be a blown fuse or it can be a trailer plug problem. This truck has a history of the terminals in the plug breaking and causing similar issues....

Q: What would cause a loud bang and hard shift into and out of gear in rear end area of Dodge 3500 auto trans.

Hi There, This is usually a case of a bad U-joint that has excess play in it. As the transfer of torque moves from the transmission through the drive line to the rear end, this puts a tremendous amount of...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...