Manifold Absolute Pressure Sensor
2021 Hyundai Tucson · 2.5L I4
Sensor Type
piezoresistive
Waveform Type
dc-variable
Location
Mounted on intake manifold plenum, center-rear of engine above throttle body
Pins
3-pin connector
Timebase
500ms/div for throttle snap test, 50ms/div for intake pulse analysis
Voltage Scale
1V/div
Trigger
2.5V, rising edge
Wiring
Pin 1: 5V reference (red or orange), Pin 2: Sensor ground (black), Pin 3: Signal output (green, yellow, or gray)
Expected Voltage Range
At Idle
0.8V to 1.6V
At Higher RPM
4.2V to 4.8V
Expected Pattern
Steady DC voltage at idle with rhythmic oscillation matching intake pulses, immediate response to throttle changes
Known-Good Waveform
At idle, expect 1.0-1.5V corresponding to 15-21 inHg vacuum. With engine off and key on, sensor should read 4.5-4.7V (atmospheric pressure). On a 50ms/div timebase, visible intake pulse oscillations of 0.1-0.2V amplitude should be present at idle, frequency matching engine RPM. Snap throttle should show immediate rise to 4.3-4.6V with smooth, rapid return to idle vacuum.
Common Failure Patterns
Voltage fixed near 4.5V regardless of engine running or manifold vacuum
Cause: Ruptured MAP sensor diaphragm or vacuum port blocked/disconnected
Voltage below 0.5V at idle or does not change with throttle input
Cause: Internal sensor failure, signal wire short to ground, or failed 5V reference circuit
Diagnostic Tips
Use MAP sensor data to verify engine mechanical condition - healthy engine shows clear, consistent intake pulses at idle. Compare MAP voltage to barometric pressure at key-on/engine-off (should be within 0.2V). Hyundai Smartstream engines use MAP sensor extensively for variable valve timing control; erratic MAP signal can cause VVT-related codes P0010-P0014.
Related Diagnostic Trouble Codes
P0105P0106P0107P0108P0109
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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