Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
2004 Mazda 3 L4-2.3LFACTORY OEM SERVICE PROCEDURE
Manifold Pressure/Vacuum Sensor: Testing and Inspection
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR INSPECTION
NOTE: Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart.
Voltage Inspection
1. Remove the MAP sensor with the connector still connected. (See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR REMOVAL/INSTALLATION.)
2. Remove the vacuum hose of the MAP sensor.
3. Verify that the voltage at PCM terminal 2AL is within the specification when the ignition switch is turned to the ON position.
- If not within the specification, replace the MAP sensor.
Voltage
2.69-4.37 V
4. Install the vacuum pump.
5. Turn the ignition switch to the ON position.
6. Verify that change in voltage is within the specification when a vacuum of 30 kPa {225 mmHg, 8.86 inHg} is applied using a vacuum pump.
- If not within the specification, replace the MAP sensor.
Voltage variance
1.16-1.27V
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harness for an open or short circuit. (Continuity inspection)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- MAP sensor terminal A and PCM terminal 2AA
- MAP sensor terminal D and PCM terminal 2AL
- MAP sensor terminal C and PCM terminal 2W
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- MAP sensor terminal C and power supply.
- MAP sensor terminal C and body GND.
- MAP sensor terminal D and power supply.
- MAP sensor terminal D and body GND
NOTE: Before performing the following inspection, make sure to follow the procedure as indicated in the troubleshooting flowchart.
Voltage Inspection
1. Remove the MAP sensor with the connector still connected. (See MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR REMOVAL/INSTALLATION.)
2. Remove the vacuum hose of the MAP sensor.
3. Verify that the voltage at PCM terminal 2AL is within the specification when the ignition switch is turned to the ON position.
- If not within the specification, replace the MAP sensor.
Voltage
2.69-4.37 V
4. Install the vacuum pump.
5. Turn the ignition switch to the ON position.
6. Verify that change in voltage is within the specification when a vacuum of 30 kPa {225 mmHg, 8.86 inHg} is applied using a vacuum pump.
- If not within the specification, replace the MAP sensor.
Voltage variance
1.16-1.27V
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harness for an open or short circuit. (Continuity inspection)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- MAP sensor terminal A and PCM terminal 2AA
- MAP sensor terminal D and PCM terminal 2AL
- MAP sensor terminal C and PCM terminal 2W
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- MAP sensor terminal C and power supply.
- MAP sensor terminal C and body GND.
- MAP sensor terminal D and power supply.
- MAP sensor terminal D and body GND
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.