What To Do When You See U010c Code In a 6.7 Cummins?

Engine error codes are there to help you recognize and diagnose any potentially critical issues with your engine. One of those error codes is U010c.

So, what does the U010c code 6.7 Cummins engine mean?

The error code U010c translates to “lost communication with turbocharger or supercharger control module.” This means that the other control modules in your engine have lost communication with the turbocharger. This code is mostly triggered by an open or short in the CAN bus circuit, no power to the turbo, or a fault in the ECU.

In the upcoming parts, details about this error code and the solution will be discussed.

Diagnosing the U010C Code in 6.7 Cummins

The code means the turbocharger is no longer communicating with other modules of the engine. It is necessary to make a preliminary diagnosis to repair the U010C code and identify the actual issue.

First, check the technical service bulletin (TBS) on the technical details for code U010C for your 6.7 Cummins model. Look for other diagnostic fault codes related to battery, ignition, or bus communication. Usually, the manufacturer provides necessary fixes so it can help you diagnose the actual problem in less time.

If there are no other fault codes, the code may have stemmed intermittently or the culprit may be a dead battery. Clear the code and check if it returns. In that case, make a visual diagnosis for broken or loose wires around the CAN bus related and TSCM module A components.

If there are other diagnostic trouble codes indicating turbocharger operational issues, it can mean there is a problem with the CAN network. In that case, fix the other trouble codes for problems of the CAN bus and see if the problem remains.

If it does, there may be a circuit failure causing loss of power or ground to the TSCM-A. Check all the fuses and grounds to identify the issue.

U010c Code In 6.7 Cummins: Causes, Symptoms, and Solution




Dead Battery
  • Malfunction Indicator Light on
  • Check engine light on, 
  • Lack of engine power, 
  • The engine can run when cold, but knocks on acceleration when warm or won’t start if cold, 
  • Performance issue related to turbocharger
Repair or replace the battery
CAN circuit open or short causes U010c Code in 6.7 CumminsClean any corroded connector terminals and replace any damaged wires. Repair the circuit if the voltage test fails.
No power to the turbocharger control module AReplace the actuator, fuse, or wiring
A faulty ECMReplace the ECM.

Reason One: Dead Battery

The TSCM-A receives and transmits messages from the PCM to other components and requires high voltage for its operation. If there is not enough voltage supply, the code can appear. 


Before diagnosing any other components, check if your battery is operating well. Check the battery and the charging system and if it’s faulty, repair or replace the battery.

To test the battery, visit an auto professional and get a load test done. Make sure to disconnect the one battery and test them individually to get the correct reading.

If the battery reads 14 volts, the battery is in good health. Check the wires for corrosion or lose connection as it can prevent proper voltage supply.

If the battery voltage reads below 12 volts, your battery needs to be replaced. To replace the battery of the 6.7 Cummins, follow the owner’s manual for your specific model.

Reason Two: CAN Circuit Open or Short

All the modules in your 6.7 Cummins diesel engine are connected through the CAN (Controller Area Network). So, since the turbocharger lost communication with other modules, it’s highly possible that something is wrong with the CAN bus system.

Here are the precise steps to diagnose your CAN bus system-

Check for Damage or Corrosion:

  1. First, you will have to unplug the connector at the actuator. But before that make sure to disconnect the negative battery cable. 
  2. Look for your CAN bus communication connections under the hood, usually on the bulkhead or in the fender well.
  3. Once you’ve found it, check the connectors and wiring. See if there’s scraping, rubbing, opened wires, bare wires, burn spots, or melted plastic. 
  4. Use a digital multimeter to test the datalink connector where pin 6 indicates CAN high and pin 14 indicates CAN low. 
  5. Also, examine the terminals inside the connectors by pulling them apart. Look for green tints or burnt spots as they indicate corrosion.


If the connector is corroded, use an electrical contact cleaner and a plastic bristle brush. Allow the terminals to dry before applying electrical grease. Have them replaced if the wiring is damaged.

If you do not get the proper voltage readings, repair the power or ground circuit problem by getting expert help. It may cost you around $200.

Reason Three: Turbocharger Control Module Has No Power

The turbocharger control module (TSCM) Module A, or the actuator, controls the boost pressure by converting electric energy into kinetic energy. So, it makes sense that your engine will display error codes when the actuator is not getting power.

So, either there is something wrong with the actuator or the actuator connection.

Taking your actuator out and testing it with a diagnostic scan tool will let you know if it has problems.

It’s located right next to the turbocharger, behind the front passenger wheel. 

  • You’ll need to drain the coolant from your truck’s system, then take off the front passenger wheel to get to the actuator. 
  • To remove the actuator, first remove the electrical connection, then unscrew the bolts. 
  • You could just connect it to the turbo’s harness and test it. Then have someone else turn the key on. 
  • Upon turning on, the actuator’s gear should move all the way to the left. When it’s turned off, the gear should move back to its original position. 
  • There may be a problem with the actuator if it does not make this sound or if it makes a buzzing sound while moving.

In the next step, you need to test if the wiring and fuse for power and ground is proper.

  • The fuse box is located in front of the vehicle, under the hood. 
  • Open up the plastic cover to find all the fuses there. The actuator fuse is the F75; check if it’s blown. Also, the connections to and from it are fine.
  • Then, we will have to test the wiring. 
  • Turn your key on and use a multimeter to test the continuity of the plug through which the actuator is connected. If there is continuity, the wiring is fine.

Voltage Test:

  1. For this, you will have to reconnect the battery but keep the actuator disconnected. 
  2. Using your voltmeter, connect the red lead to each battery voltage supply coming into the connector, and the black lead to the ground.
  3. The multimeter should be able to give you a reading of the voltage of the battery. 
  4. Also, confirm that you have good grounds as well. The red lead of your voltmeter should be connected to the battery positive (B+), and the black lead should be connected to each ground circuit. At each connection, you should see the battery voltage. 
  5. In the next step, we will check the two communication circuits to make sure they are working properly. But first, you need to determine which circuits are CAN C+ and CAN C-.
  6. Connect the red lead of your voltmeter to CAN C+ while connecting the black lead to good ground. You should see about 2.6 volts with the key on and the engine off. 
  7. You will need to connect the red voltmeter lead to the CAN C- circuit. Approximately 2.4 volts should be visible, fluctuating slightly. 


If the battery voltage at the connector does not read right, repair the power or ground circuit. If the fuse is blown, replace it with another with the correct amperage. The actuator fuse is usually 10 amps. Just take out the blown fuse and install a new one.

Or, if the wiring is bad, you will need to replace that too.

Sometimes, reprogramming the software also removes the code and fixes the problem.

However, if the problem persists with the turbocharger, then you need to replace it with a new one. Here is a video that will easily explain the whole process-

Reason Four: A Faulty ECM

If all else fails, the only problem left is a faulty ECM. Since the ECM detects any issues and stores them in its memory, if everything else is fine, it’s probably the ECM.

In this case, you will encounter a lot of error codes. If the fault is with the ECM, this needs to be addressed as soon as possible.

It takes a great deal of expertise and knowledge to test an ECM. So, if you suspect that, you’d better call a mechanic who can do it. 


In the event that your ECM malfunctions, reflashing it can solve the issue. If reflashing does not work, you must replace it. Visit the Cummins dealers to have your ECM checked.

A new ECM will cost about $600 excluding the dealer charge, which may vary from $1300-$2300, depending on the severity of the issue.

The Last Resort

The only thing left is to seek assistance from a trained automotive diagnostician if communication is still not possible or if the U010C fault code cannot be cleared. The cost will vary depending on the problem; expect to spend a few hundred dollars for a serious issue. 

6.7 Cummins Turbocharger Maintenance

Your Cummins diesel engine’s turbocharger is a big deal. In the same way as other turbo engines, the 6.7L Cummins needs extra care and maintenance. Here are some tips for taking care of a 6.7L Cummins turbo.

Keeping Your Oil Clean

The compression valves, intake fans, and exhaust fans of turbocharged engines require quality engine oil to be lubricated. As a result, they work better and wear less. It is best to change the oil in a turbocharger every 5,000 miles in order to maximize its efficiency.

Warming Up The Engine

When the engine oil gets cold, it thickens and doesn’t flow as well. Until the oil thins and warms up, moving parts are more prone to wear and tear.

Go easy on the accelerator pedal when driving a cold truck to prevent unnecessary wear on the turbo and oil pump. Don’t go full throttle until the oil gauge reaches its optimum temperature.

Keep the Engine Cool

While driving, turbochargers produce a lot of heat. As soon as you turn off the engine, the residual heat will boil the oil. In the long run, this can result in the accumulation of carbon particles, which can result in the corrosion of the metal.

After driving, leave the engine running for a few minutes before turning it off.

Read More-

  1. Causes and Fixes of P0430 Code Dodge Charger
  2. Easy Way to Fix P0542 Code In 6.7 Cummins


Is the 6.7 Cummins a good engine?

Yes, the 6.7 Cummins is a good engine. Despite this, Cummins 6.7L diesel are more susceptible to turbocharger problems, EGR system problems, and head gasket failures. But if maintained properly, it can run from 250,000 to 350,000 miles.

What causes Cummins turbo actuator failure?

The most common problems behind actuator failure are carbon buildup in the turbocharger, failed thrust, and EGR valve problems.

Can I drive with a faulty actuator?

Yes, it’s safe to drive even with a faulty actuator. But the longer you keep on driving with it, the more risk you put your engine at. So, it’s better to replace your actuator before going for a drive.


The U010c code in the 6.7 Cummins engine means the turbocharger lost communication with all the other modules. So, the problem is bound to be in the CAN system, through which the modules communicate. Other than that, the turbocharger or the ECM itself could be faulty.

The diagnosis and solution might be too complicated or confusing. If that’s the case, it’s better to get expert help rather than do it yourself.

Also, do note that taking care of the turbo will increase the longevity of your 6.7 Cummins diesel engine.


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