The Manifold Absolute Pressure (MAP) sensor measures intake manifold pressure. In turbocharged engines, this is the primary boost pressure measurement. The ECU uses MAP for load calculation, fuel injection, and boost control.
Vue d'ensemble
MAP sensors output a voltage proportional to absolute pressure (vacuum to boost). Modern sensors use piezoelectric or strain gauge elements with built-in signal conditioning.
Sensor Ranges
- 1 bar — naturally aspirated only (vacuum to atmospheric)
- 2.5 bar — low-boost applications
- 3-4 bar — typical diesel/moderate boost
- 5+ bar — high-performance applications
ECU Usage
- Engine load calculation
- Boost pressure feedback
- Altitude compensation
- Barometric reference (at startup)
Calibration Considerations
- High-boost tuning may require sensor upgrade
- MAP sensor scaling must match hardware
- Sensor location affects readings (pre/post throttle)
Diagnostics
- MAP range/performance faults
- MAP/MAF correlation errors
- Implausible boost readings
Best Practices
- Verify MAP sensor range covers target boost
- Check vacuum lines for leaks
- Use quality sensors for accurate readings
