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.
1990 Mazda 323 Base, StandardFACTORY OEM SERVICE PROCEDURE
EGR Position Sensor
- Backprobe EGR position sensor connector with voltmeter. See Fig 1 .
- With EGR vacuum hose disconnected, connect vacuum pump to the EGR valve. Turn ignition on and check voltages at connector. Use EGR POSITION SENSOR VOLTAGE table to compare results.
- If voltage is not correct at terminals A and B, check wiring harness and connection at ECU connector terminals 2A and 2C. If voltage is not correct at terminal C, check sensor resistance, harness and ECU connector terminal 2F.
- Check sensor resistance according to EGR POSITION SENSOR RESISTANCE table. If resistance is not within specifications, replace sensor.
EGR POSITION SENSOR VOLTAGE
| Terminal | Volts | |
|---|---|---|
| "A" | 4.5-5.5 | |
| "B" | Less Than 1.5 | |
| "C" | ||
| Without Vacuum | .25-.95 | |
| With Vacuum | Approx. 4 | |
EGR POSITION SENSOR RESISTANCE
| Terminals | Ohms |
|---|---|
| "A"-"B" | 5000 |
| "A"-"C" | 700-5000 |
| "B"-"C" | 700-5000 |
Factory Service Tools
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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.
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