P0712 is the generic OBD-II code for Transmission Fluid Temperature Sensor “A” Circuit Low Input. OEM service information and training material use that definition consistently, and Toyota-style diagnostics specifically identify P0712 as the low-input version of the transmission temperature sensor fault family.

P0711 is the generic OBD-II code for Transmission Fluid Temperature Sensor “A” Circuit Range/Performance. OEM service information describes it as a fault where the transmission fluid temperature signal is present but behaves outside the expected range, or the temperature reading does not change the way the controller expects during operation. Toyota service manuals describe P0711 as a performance/rationality fault in the ATF temperature sensor output, not just a simple hard open or hard short.

P0218 is the generic OBD-II code for Transmission Over Temperature Condition or Transmission Fluid Over Temperature Condition. Heavy-duty and OEM service references use essentially that same definition, and one published diagnostic reference shows the code setting when transmission sump temperature exceeds 126°C / 252°F for 10 seconds on that application.

P0217 is the generic OBD-II code for Engine Over Temperature Condition or Engine Coolant Over Temperature Condition. Manufacturer and service references describe it as a code set when the ECM detects that coolant temperature has reached an overheat threshold. Hino’s service manual states P0217 is issued when an over temperature condition is detected, and another published reference notes the code is triggered at about 110°C / 230°F on that application.

P0117 is the generic OBD-II code for Engine Coolant Temperature Circuit Low Input. Factory service information describes it as a condition where the ECM sees the ECT sensor signal voltage as too low. Because the ECT sensor is a thermistor, a very low signal voltage usually makes the computer interpret the engine coolant temperature as extremely hot, even if the engine is actually cold.

P0125 is the generic OBD-II code for “Insufficient Coolant Temperature for Closed Loop Fuel Control.” In factory diagnostic information, the code sets when engine coolant temperature does not rise enough, fast enough, for the ECM to enter normal closed-loop fuel control. Toyota service manuals describe this as the engine failing to reach the temperature needed for closed-loop operation within a monitored time window, and they point first to the thermostat, cooling system, and ECT sensor as the main trouble areas.

P0116 is the generic OBD-II code for Engine Coolant Temperature Circuit Range/Performance. In manufacturer service information, it is used when the PCM/ECM sees an engine coolant temperature signal that does not behave the way it should, not simply when the circuit is fully open or shorted. Toyota manuals describe P0116 as a range/performance problem, and Mitsubishi service info lists the most likely causes as the ECT sensor, harness/connector damage, or the ECM.

The turbo actuator is a critical part that controls:

👉 Boost pressure
👉 Wastegate or VGT (variable geometry)
👉 Turbo response

P003A is a generic OBD-II turbo-related code that means:

👉 “Turbocharger Boost Control Position Exceeded Learning Limit”

P00AF is a generic OBD-II code for “Turbocharger/Supercharger Boost Control ‘A’ Module Performance.” Multiple manufacturer bulletins and VAG references use essentially that same definition.