Loss of power: Codes, Causes & Fixes
Noticeable loss of power usually has one of a few causes: the engine computer has entered limp mode, a turbocharged engine is underboosting (P0299), airflow is restricted by a dirty MAF sensor or clogged air filter, fuel pressure is low, or the exhaust is blocked by a failing catalytic converter or full diesel particulate filter. Read all stored codes and freeze-frame data first – they usually show which of these paths to follow.
214Codes
3.1Average severity
22%High or critical
9%DIY-friendly
Severity distribution
Most viewed
P0174
Powertrain
The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction…
Moderate
P0300
Powertrain
The engine computer sees misfires that jump between cylinders or hit several cylinders at once.
High
P0420
Powertrain
The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly.
Low
P0430
Powertrain
The bank 2 converter on a V6, V8 or split-exhaust engine isn't cleaning the exhaust well enough.
Low
P0101
Powertrain
The MAF sensor's airflow reading doesn't match what the engine computer expects…
Low
P0171
Powertrain
The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees…
Moderate
All codes (177)
P0001
Powertrain
The PCM can't drive the solenoid that meters fuel into the high-pressure pump. Often a no-start…
High
P0008
Powertrain
Camshaft timing on bank 1 has drifted from the crankshaft. Often a stretched timing chain.
Moderate
P0012
Powertrain
The bank 1 intake cam lags behind the angle the PCM wants, often from chain stretch or weak oil…
Moderate
P0014
Powertrain
The bank 1 exhaust cam won't follow its target and stays too far advanced; think oil, valve…
Moderate
P0015
Powertrain
The bank 1 exhaust cam sits later than commanded; a stretched chain or stuck exhaust phaser…
Moderate
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
P0019
Powertrain
The bank 2 exhaust cam signal doesn't match the crankshaft; chain, bank 2 exhaust phaser…
Moderate
P0022
Powertrain
The bank 2 intake cam can't advance as far as the PCM asks; phaser, oil pressure or a worn bank…
Moderate
P0045
Powertrain
The engine computer sees an open or shorted circuit to the solenoid that controls turbo boost.
Moderate
P0046
Powertrain
The boost control solenoid circuit is intact, but boost doesn't follow what the solenoid…
Moderate
P0087
Powertrain
Measured fuel pressure has dropped well below what the engine computer is asking for.
High
P0089
Powertrain
The fuel pressure regulator is getting its commands but pressure isn't responding the way it…
Moderate
P0090
Powertrain
The engine computer sees an electrical fault in the wiring or coil of the fuel pressure control…
Moderate
P0093
Powertrain
Rail pressure is dropping faster than injection explains: fuel may be escaping. Stop and check…
Critical
P0102
Powertrain
The MAF signal is too weak for the PCM to accept, so it treats the circuit as dead…
Moderate
P0107
Powertrain
The MAP signal has fallen to almost zero volts, usually from a lost 5-volt reference or an open…
Moderate
P0121
Powertrain
The throttle position reading is electrically valid but doesn't agree with engine load, airflow…
Moderate
P0122
Powertrain
The throttle position signal fell to nearly 0 volts, lower than a closed throttle could ever…
Moderate
P0152
Powertrain
Bank 2's front O2 sensor is pinned high – usually voltage leaking in from its heater wire…
Moderate
P0171
Powertrain
The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees…
Moderate
P0174
Powertrain
The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction…
Moderate
P0190
Powertrain
The signal from the fuel rail pressure sensor has dropped out or become unusable to the engine…
Moderate
P0191
Powertrain
The rail pressure reading is electrically valid but doesn't make sense for how the engine…
Moderate
P0193
Powertrain
The rail pressure sensor signal is stuck near the 5-volt limit, above anything a working sensor…
Moderate
P0201
Powertrain
The ECU sees an open or faulty electrical circuit to injector 1, so cylinder 1 is probably…
Moderate
P0202
Powertrain
Injector 2's circuit is open or out of range; on an inline-four it's a middle cylinder under…
Moderate
P0203
Powertrain
The ECU sees no normal electrical response from injector 3: its coil, its wiring or its driver…
Moderate
P0204
Powertrain
The circuit to injector 4 is open or out of range; on most transverse engines that's…
Moderate
P0205
Powertrain
The ECU sees a broken or faulty electrical circuit to the cylinder 5 injector, so that cylinder…
Moderate