Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Trouble Code (DTC) Information ICM-6C78
Condition
The serial number of each control module in the infotainment system is stored in the central electronic module (CEM). The stored numbers are compared with the serial numbers of the control modules at start up. If the numbers do not correspond, that particular control module is blocked and the function is not available. The blocking function for non-approved control modules is designated security on MOST.
The infotainment control module (ICM) checks whether the traffic message channel module (TMC) is in the approved list stored in the central electronic module (CEM).
The diagnostic trouble code (DTC) is stored if the infotainment control module (ICM) registers that the traffic message channel module (TMC) is not in the approved list.
The diagnostic trouble code (DTC) can be diagnosed when the ignition is on for at least 12 seconds and the battery voltage is above 11 V and security on MOST is activated.
Substitute Value
- None.
Possible Source
- Replacement with a traffic message channel module (TMC) which is not approved in the list stored in the central electronic module (CEM)
- Software not downloaded when replacing the traffic message channel module (TMC)
- Failed or incomplete software download for the traffic message channel module (TMC).
Fault symptom[s]
- Traffic information is not displayed or updated.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
No obligation. See pricing before you book.