Manifold Absolute Pressure Sensor
2018 Toyota Camry · 2.5L I4 Hybrid
Sensor Type
piezoresistive
Waveform Type
dc-variable
Location
Intake manifold rear, center between cylinders 2 and 3, or integrated into throttle body on some model years
Pins
3-pin connector
Timebase
500ms/div for throttle snap test
Voltage Scale
1V/div
Trigger
N/A - DC signal
Wiring
Red/Yellow (5V reference), Black/Blue (sensor ground), Green (MAP signal output)
Expected Voltage Range
At Idle
0.9V to 1.6V
At Higher RPM
4.2V to 4.7V
Expected Pattern
DC voltage proportional to manifold vacuum, 0.9-1.6V at idle (high vacuum), 4.2-4.7V at WOT (atmospheric)
Known-Good Waveform
MAP sensor outputs stable DC voltage inversely proportional to manifold vacuum. At idle, expect 0.9-1.6V representing 16-20 inHg vacuum on warm engine. Key-on engine-off (KOEO) should show 4.4-4.7V (barometric pressure). During rapid throttle opening, voltage should rise smoothly to 4.2-4.7V within 100-200ms, then drop back to idle levels when throttle closes, showing brief overrun vacuum spike to 0.5-0.8V.
Common Failure Patterns
Voltage stuck at or near 4.5V regardless of engine vacuum, poor fuel economy
Cause: Disconnected or cracked vacuum line to MAP sensor, failed internal diaphragm
Erratic voltage fluctuation at idle, hunting or surging idle speed
Cause: Vacuum leak in intake manifold or throttle body gasket, PCV system leak
Diagnostic Tips
Hybrid Camry Atkinson cycle creates higher vacuum levels than Otto cycle engines; expect lower idle MAP voltages. Verify 5V reference and ground circuits before replacing sensor. Some model years integrate MAP into throttle body assembly requiring complete unit replacement.
Related Diagnostic Trouble Codes
P0105P0106P0107P0108P0109
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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