Trouble codes › By vehicle › Toyota Tacoma
Common check-engine codes on the Toyota Tacoma
2005-2023
Tacomas run a long time, so most codes are age and mileage related: lean codes, catalytic converters and EVAP, on the 2.7L four-cylinder and the 4.0L and 3.5L V6s.
Most common: P0171, P0174, P0420, P0441, P0300, P0138.
P0171 System Too Lean (Bank 1)
P0171 means bank 1 is running lean (too much air or too little fuel), most often from a vacuum leak or a dirty MAF sensor.
On the Toyota Tacoma: Lean codes (often with P0174 on the V6) are common: a dirty MAF sensor is the first thing to try, then vacuum leaks and the intake boot.
P0171: causes, can I keep driving, and what to check first →
P0174 System Too Lean (Bank 2)
P0174 means bank 2 is running lean (too much air or too little fuel), most often from a vacuum leak or a dirty MAF sensor.
On the Toyota Tacoma: Bank 2 lean on the V6, usually set with P0171: look for a shared cause such as the MAF sensor or a vacuum leak.
P0174: causes, can I keep driving, and what to check first →
P0420 Catalyst System Efficiency Below Threshold (Bank 1)
P0420 means the catalytic converter on bank 1 isn't cleaning the exhaust well enough, usually a worn converter, an exhaust leak or a lazy oxygen sensor.
On the Toyota Tacoma: Catalyst efficiency at higher mileage, often with P0430 on the V6. Check for exhaust leaks and misfires first.
P0420: causes, can I keep driving, and what to check first →
P0441 Evaporative Emission System Incorrect Purge Flow
P0441 means the EVAP purge system isn't flowing fuel vapor to the engine as expected, often a stuck purge valve.
On the Toyota Tacoma: EVAP codes (P0441, P0455, P0456) are common on Tacomas: the purge valve, gas cap and canister hoses.
P0441: causes, can I keep driving, and what to check first →
P0300 Random/Multiple Cylinder Misfire Detected
P0300 means the engine is misfiring in more than one cylinder, often from worn plugs or coils, a vacuum leak or low fuel pressure.
On the Toyota Tacoma: Misfires: plugs and coils on higher-mileage trucks.
P0300: causes, can I keep driving, and what to check first →
P0138 O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
P0138 means bank 1's rear oxygen sensor is stuck at high voltage, from a failed sensor, wiring or a rich condition.
On the Toyota Tacoma: Rear oxygen sensor high voltage: usually an aging sensor.
P0138: causes, can I keep driving, and what to check first →
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Common codes and known problems as widely reported for these model years; your vehicle may differ. Check nhtsa.gov/recalls and ask a dealer about service bulletins for your VIN, and confirm in your service information.