What this code means

The PCM detected that the intake airflow system is not operating within expected parameters based on the MAF sensor self-diagnostic check. This code is extremely common on GM turbo engines, especially the 1.4T and 1.5T Ecotec engines in the Cruze, Malibu, Sonic, and Trax. A torn PCV diaphragm or failed internal membrane inside the valve cover is one of the top causes.

Symptoms

• Check Engine Light
• Rough idle
• Reduced power
• Poor acceleration
• Increased fuel consumption
• Engine may enter limp mode on turbo models

Common causes

• Torn PCV valve diaphragm or membrane in valve cover
• MAF sensor contamination (dust, oil residue)
• Vacuum leak (cracked hoses, loose clamps)
• Clogged or restricted air filter
• Throttle body carbon buildup
• Deformed air filter housing
• Intake manifold gasket leak

Diagnostic steps

1. Inspect PCV system and valve cover diaphragm for tears
2. Clean or test MAF sensor
3. Perform smoke test for vacuum leaks
4. Inspect air filter and housing
5. Check throttle body for carbon buildup
6. Monitor MAF readings with scan tool

Repair notes

On turbo Ecotec engines, replace the valve cover assembly (contains integrated PCV diaphragm) first. On other engines, clean MAF sensor and check for vacuum leaks.

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