c056d-39 with service suspension system and service leveling system messages

[dmarsh07]

I've got a 2017 Tahoe premier with C056D-39 code (electronic control unit hardware internal electric failure) with service suspension system and service leveling system messages I suspected the compressor to be bad it was making some awful noises and wouldn't run if I jumped the relay so I replaced it and had a shop check the ride height sensors was told they where responding and cleared the codes but the C056d-39 keeps coming back with the two service messages when I've tired to search the code I've found very Littie info looking for some advice I'm guessing there's a bad module someplace but not sure where to start

 

[Joseph Garcia]

Dr. Google offered this. The '39' suffix to the code indicates a steering issue.

The C056D-39 trouble code in GM vehicles indicates an internal hardware failure within the power steering control module (PSCM). This fault can lead to heavy steering and loss of power steering assist. To diagnose and repair it, you should first check for proper power, ground connections, and wiring integrity for the PSCM. If these are fine, a common repair involves updating the control modules with the latest software or replacing the faulty PSCM itself.

What the Code Means

• C056D:
  This code points to an internal failure in the control unit's hardware, specifically the PSCM.
• -39:
  This is a specific detail about the nature of the failure, often related to a component within the power steering system.

Symptoms You Might Experience

• No or intermittent power steering assist
• A heavy or difficult-to-turn steering wheel
• Warning lights on the dashboard, such as the ABS or StabiliTrak light

Troubleshooting Steps

1. 1. Inspect Power & Ground:
   Check the power and ground connections to the PSCM, as well as the overall vehicle battery and charging system.
   
   
2. 2. Check Wiring:
   Inspect the wiring harness and connectors associated with the PSCM for damage, corrosion, or loose connections.
   
   
3. 3. Update Modules:
   In some cases, updating the EBCM and PSCM firmware can resolve the issue.
   
   
4. 4. Replace PSCM:
   If the code persists after checking connections and updating software, the most likely solution is to replace the power steering control module. The new module may also require programming and calibration.
   

Important Note: GM diagnostic trouble codes, especially internal ones like C056D, often indicate a failure within the control module itself and require professional diagnosis, especially for programming.

 

[dmarsh07]

So that's where I'm lost is that I'm not having any troubles with steering or messages displayed about it

 

[Joseph Garcia]

You may not be experiencing any noticeable issues now, but that could change at any time. I suggest reviewing the troubleshooting steps above and see what you find.