A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
Possible causes
- An air leak after the mass air flow sensor: a cracked hose, a loose clamp
- The crankcase vent pipe with a valve at the turbo inlet (1.4 turbo engine)
- A plugged crankcase vent orifice — high crankcase pressure (1.4 and 1.5 turbo engines)
- The air filter housing is assembled wrongly or the baffle is missing (Cruze)
What you can do yourself
- Check the intake from the air filter to the throttle: cracked hoses, loose clamps, a filter housing not fully closed — air sucked in past the sensor sets this code.
- 1.4 turbo engine (Cruze, Aveo/Sonic, Tracker/Trax up to 2019): per a GM bulletin a common cause is the valve in the crankcase vent pipe at the turbo inlet; the pipe is replaced.
- If oil is also leaking from the crankshaft seals, per a GM bulletin the crankcase vent orifice is plugged (1.4 and 1.5 turbo engines): it is cleaned or replaced and the crankcase pressure measured.
- Don’t replace the mass air flow sensor at random: per a GM bulletin replacing it usually doesn’t clear this code.
Stop and don’t drive on if:
- The Check Engine light is flashing
- The temperature gauge is in the red or the overheating light is on
- The red oil pressure light is on
- Smoke from under the bonnet, a burning or petrol smell
- Strong jerking, knocking from the engine, or the car barely moves
This is the GM meaning (Chevrolet, Cadillac, GMC). On other makes this number means something else: if your car isn’t made by GM, change the make at the top.
Source: GM 20-NA-047, PI0907C, 13-00-89-004 (static.nhtsa.gov)
The explanation comes from the error code reference in the AvtoElektrik PRO app.