How does a fault code arise in the Transmission group?
The transmission control unit watches input and output speed sensors, fluid temperature, pressure and shift solenoids, and the behaviour of the clutches and torque converter. In an automatic transmission, shifts happen because those solenoids manage hydraulic pressure.
Codes come in three main kinds: an electrical fault in a solenoid circuit; input and output speed not matching the expected ratio, that is, slip; and pressure or temperature values leaving their window. Slip codes can result from mechanical wear or from low or degraded fluid — both produce the same code.
So the first step with transmission codes is almost always the same: fluid level and condition, then live data alongside fluid temperature. Note also that some transmission codes are a reflection of a fault on the engine side; transmission codes should not be judged before the engine codes are resolved.
Fault codes in this group
The database holds 36 codes in this group. Each code has its own page with the meaning, possible causes and diagnostic steps:
Read fault codes on your own vehicle
With an ELM327-based BLE OBD2 adapter, CarCoding reads confirmed, pending and permanent fault codes separately, pulls the freeze frame and explains every code in plain language. Clearing codes is done from the app as well. The app is free to download.
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Data source: the CarCoding fault code database. Code definitions follow the SAE J2012 standard; manufacturers may use different wording for their own codes. Everything on this page is generated from the code-specific database records.