Toyota 30CG5100.cuw Engine Control Firmware

30CG5100.cuw is a Toyota engine control calibration associated with the engine control module (ECM). The ECM manages engine operation, including the fuel delivery calculations that help maintain the intended air-fuel mixture. Toyota lists calibration ID 30CG5100 as an updated calibration in service bulletin T-SB-0166-19, which addresses a malfunction indicator light associated with specified diagnostic trouble codes.

What the calibration addresses

The bulletin lists codes P0171 and P0174 for a lean fuel mixture, and P0172 and P0175 for a rich fuel mixture. A lean condition means the measured mixture has relatively too much air or too little fuel. A rich condition means it has relatively too much fuel. The ECM monitors feedback from the engine’s sensors and adjusts fueling during operation.

The bulletin also lists P1604, a startability malfunction code. These codes describe the conditions addressed by the bulletin, not proof that every vehicle with one of them needs this calibration. Diagnosis still depends on the vehicle and the condition causing the warning light.

Vehicles covered by the bulletin

T-SB-0166-19 covers the 2009 Toyota Tundra and 2009–2018 Toyota Sequoia. This is the bulletin’s combined vehicle scope, not a claim that 30CG5100 applies to every listed model and year. The service record identifies it as an updated calibration for the bulletin, but does not specify the exact vehicle application or describe the internal software changes.