What does code P1789 mean on Audi vehicles?
The transmission control module receives an error related to idle speed intervention from the engine control module, affecting idle stability.
OBD-II Code Audi
P1789 — Audi — Idle Speed Intervention Circuit Error Message from Engine Control Module
The transmission control module receives an error related to idle speed intervention from the engine control module, affecting idle stability.
Common symptoms
- Unstable idle speed
- irregular engine behavior
Possible causes
- Communication error between control modules
- CAN bus fault
Initial recommendation
Perform CAN bus diagnostics and verify communication between engine and transmission control modules.
Safety notice
This information is for guidance only. Brand-specific codes may vary by model, year, engine, transmission and vehicle configuration. It does not replace a physical inspection or diagnosis by a qualified mechanic. If the vehicle is unsafe to operate, avoid driving it and seek professional inspection.
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