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.
1993 Subaru SVXFACTORY OEM SERVICE PROCEDURE
Code 23: Airflow Sensor
NOTE:
Refer to illustration for ECU connector and terminal identification. See Figure
.
- Check ECU input signal for airflow sensor. Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B60, terminal No. 5 (backprobe) and ground. Voltage should be 0-0.3 volts. Check voltage between ECU connector B60, terminal No. 6 (backprobe) and ground. Voltage should not exist. Check voltage between ECU connector B59, terminal No. 11 (backprobe) and ground. Voltage should be 10-13 volts.
- With engine idling, check voltage between ECU connector B60, terminal No. 5 and ground. Voltage should be 0.8-1.2 volts. Check voltage between ECU connector B60, terminal No. 6 and ground. Voltage should not exist. Check voltage between ECU connector B59, terminal No. 11 and ground. Voltage should be 13-14 volts.
- If voltage is as specified in previous steps, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU. If voltage is not as specified in previous steps, turn ignition switch to OFF position. Disconnect ECU and airflow sensor connectors.
- Using an ohmmeter, check resistance between ECU connector B59, terminal No. 11 and sensor connector terminal No. 3 (Black/Red wire), between ECU connector B60, terminal No. 4 and sensor connector terminal No. 1 (Red wire), between ECU connector B60, terminal No. 5 and sensor connector terminal No. 4 (White wire), and between ECU connector B60, terminal No. 6 and sensor connector terminal No. 2 (Black wire).
- Resistance should be zero ohms for all circuits. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, replace airflow sensor.
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.