Manifold Absolute Pressure Sensor
2018 Toyota Corolla · 1.8L I4
Sensor Type
piezoresistive
Waveform Type
dc-variable
Location
Intake manifold, mounted on throttle body or manifold runner, passenger side
Pins
3-pin connector
Timebase
50ms/div
Voltage Scale
1V/div
Trigger
N/A - DC signal with AC ripple
Wiring
Light Green/Black (5V reference from ECM), Brown (ground), Blue/Black (signal output to ECM)
Expected Voltage Range
At Idle
0.8V to 1.5V
At Higher RPM
4V to 4.7V
Expected Pattern
Smooth DC voltage varying with manifold vacuum, pulses visible at idle corresponding to intake valve events
Known-Good Waveform
MAP sensor outputs 0.8-1.5V at idle representing 18-22 inHg vacuum, with visible ripple corresponding to intake pulses at cylinder frequency. Signal should rise smoothly to 4.0-4.7V at wide-open throttle representing atmospheric pressure. Key-on engine-off voltage should read atmospheric pressure (approximately 4.5V at sea level).
Common Failure Patterns
Voltage stuck at 4.5V regardless of throttle position, no vacuum reading
Cause: Ruptured internal diaphragm or blocked vacuum port/hose to sensor
Diagnostic Tips
2ZR-FE uses MAP sensor for backup/verification of MAF data and for engine load calculation. Verify vacuum hose integrity - common leak point at PCV valve. Compare MAP reading to known good vacuum gauge; should see 18-22 inHg at warm idle, sea level.
Related Diagnostic Trouble Codes
P0105P0106P0107P0108P0109
Always confirm waveform data with your vehicle's OEM service manual before diagnosing.
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