U0120

Lost Communication With Starter / Generator Control Module

U0120 is a generic OBD-II network diagnostic trouble code: Lost Communication With Starter / Generator Control Module. It is logged by the engine control unit when the network monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
U0120
Group
Network
System
Network
Severity
Critical (limp mode / no-start)
Need U0120 disabled?
RaceTune permanently disables any OBD-II trouble code on supported ECUs — for motorsport, off-road, and export use.
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Detailed reference content for U0120 is being prepared. What you see above — the code's group, system, and the software disable option below — is accurate and complete; the long-form explainer, common causes, symptoms, and diagnostic steps will appear here once they have been reviewed.

Vehicles where we've handled U0120

Platforms in our catalogue with confirmed U0120 coverage.

AUDI A6
2018–2020
AUDI SQ7
2017
AUDI A4
2018
AUDI SQ7 40D
2017

Related network codes

Disabling U0120 in software

RaceTune can permanently disable U0120 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECU families we can disable U0120 on

We hold the DaVinci A2L disable definitions for these families, so the exact U0120 path and mask addresses are mapped. verified marks a confirmed disable definition. We support many more — upload your file and our identifier will match it automatically.

  • Bosch MD1CP004 verified
  • Bosch MD1CP014 verified

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

Got U0120 in your scan?

Upload your ECU file — we'll identify the exact software version and confirm whether a disable is available for your car.

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