MAP/MAF - Throttle Position Correlation

What it means

The airflow the ECU measures with the MAF or MAP sensor does not match what it expects from the throttle position. In other words, more (or less) air is getting into the engine than the throttle opening suggests. This usually points to an air leak after the throttle or a sensor reading wrong.

Symptoms

• Check engine light on
• Rough or high idle
• Reduced power or limp mode
• Stalling

Probable causes

Most likely first

1. 1Vacuum or intake leak after the throttle body
2. 2Dirty MAF sensor
3. 3Faulty MAP sensor or its vacuum hose
4. 4Dirty or faulty throttle body
5. 5PCV system leak

How to diagnose it

Work through these in order before buying parts

1. 1Record the code and its freeze frame data (speed, load, temperature when it set), then clear it and see if it comes back.
2. 2Smoke-test the intake for leaks.
3. 3Compare MAF, MAP and throttle position readings on live data at idle and under load.
4. 4Clean the throttle body and MAF sensor, then perform a throttle relearn if required.
5. 5Check for technical service bulletins (TSBs) or software updates for your make and model; some codes have known factory fixes.

Common fixes

• Repair intake leaks
• Clean or replace the MAF or MAP sensor
• Clean or replace the throttle body