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TuningBot DTC Database · v4.37.15

P1909 VAG - Diagnostic Trouble Code (2 interpretations)

Manufacturer-specific interpretation for VAG. All interpretations of P1909

P · PowertrainEngineOBD2

What P1909 means

P1909
Data bus, ECM 1/2 - no signal from ECM 1 VAG · engine Data confidence 62%

The control module did not receive the expected Data bus, ECM 1/2 signal. This is the manufacturer-specific definition used by Audi.

Possible causes

  • Wiring
  • ECM 1
Applies to Audi
P1909
Transmission Temperature Sensor Circuit Open or Shorted to Power Or Ground VAG · engine Data confidence 62%

The control module detected an interruption (open circuit) in the Transmission Temperature circuit, so the expected electrical continuity was not present. This is the manufacturer-specific definition used by Volkswagen.

Applies to Volkswagen

Related and nearby codes

How to read P1909

P

Powertrain: engine, transmission and driveline systems.

1

Manufacturer-defined range: the meaning can differ between brands.

909

Specific fault index within the subsystem.

Frequently asked questions about P1909

What does P1909 mean?

Diagnostic Trouble Code (2 interpretations). The control module did not receive the expected Data bus, ECM 1/2 signal. This is the manufacturer-specific definition used by Audi.

Is P1909 generic or manufacturer-specific?

P1909 is a manufacturer-specific code. In this database it is documented for: VAG. The same number can mean something different on other brands.

Can TuningBot remove P1909 at file level?

If the fault logic lives in the ECU calibration, yes: our DTC Removal file service disables the specific fault entry. Checksum correction is not included: it is a separate, optional service. Not sure whether your case qualifies? Request a free assessment and our engineers will check your ECU file.

Other file services

ECU tuningStage 1 dyno results for VAG engines See the results →

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