Fuel & Air Metering Trouble Codes: List & Fixes
These codes (mostly P00xx–P02xx) cover how the engine computer measures incoming air and meters fuel: the mass airflow and manifold pressure sensors, oxygen sensors, fuel trim, fuel pressure and injectors. Lean codes such as P0171 and P0174 are very often caused by an unmetered air leak – a cracked intake hose or vacuum line – rather than a failed sensor. Check hoses and the air filter housing before buying parts.
193Codes
2.5Average severity
7%High or critical
26%DIY-friendly
Severity distribution
Most viewed
P0135
Powertrain
The heater inside the upstream oxygen sensor on bank 1 isn't working or its circuit is faulty.
Low
P0174
Powertrain
The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction…
Moderate
P0101
Powertrain
The MAF sensor's airflow reading doesn't match what the engine computer expects…
Low
P0113
Powertrain
The intake air temperature signal is stuck at maximum voltage, which usually means an open…
Low
P0171
Powertrain
The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees…
Moderate
P0172
Powertrain
The engine computer is pulling as much fuel as it's allowed on bank 1 and the mixture is still…
Moderate
All codes (13)
P0001
Powertrain
The PCM can't drive the solenoid that meters fuel into the high-pressure pump. Often a no-start…
High
P0016
Powertrain
The bank 1 intake cam and the crankshaft are out of step, most often from a stretched or jumped…
High
P0018
Powertrain
The bank 2 intake cam is out of step with the crankshaft on a V or boxer engine; chain wear…
High
P0087
Powertrain
Measured fuel pressure has dropped well below what the engine computer is asking for.
High
P0093
Powertrain
Rail pressure is dropping faster than injection explains: fuel may be escaping. Stop and check…
Critical
P0200
Powertrain
The ECU found a fault in the injector control circuits that it can't pin on one cylinder, often…
High
P0216
Powertrain
The ECU can't control or confirm injection timing, usually on a diesel with an electronic…
High
P0231
Powertrain
Voltage on the wire feeding the fuel pump is too low while the pump is supposed to be running.
High
P0234
Powertrain
Boost rose above the safe limit the engine computer allows, so it may cut power to protect…
High
P1285
Ford · Powertrain
Ford's cylinder head temperature sensor reports the engine is overheating. Pull over and shut…
Critical
P1299
Ford · Powertrain
The engine got so hot that the Ford PCM is shutting off fuel to cylinders to save it. Stop…
Critical
P2146
Powertrain
The shared power feed for one group of injectors is open, so every injector in that group has…
High
P2149
Powertrain
The shared supply to the second injector group dropped out, often an intermittent wiring fault…
High