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.
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HOMESERVICE MANUALSSUBARU1994LEGACY L, 4D SEDAN, FWD, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROLS - TESTS W/CODESDIAGNOSTIC CODE TESTINGCODE 22 - KNOCK SENSOR
1994 Subaru Legacy L, 4D Sedan, FWD, Standard
Code 22 - Knock Sensor
1994 Subaru Legacy L, 4D Sedan, FWD, StandardSECTION Code 22 - Knock Sensor
NOTE:
Refer to illustration for ECU connector and terminal identification. See Figure
.
- Turn ignition on. Measure voltage between ECU connector B56, terminal No. 5 (backprobe) and ground. If voltage is not 3-4 volts, check ECU terminals for poor contact or replace ECU. If 3-4 volts are present, go to next step.
- Turn ignition off. Disconnect knock sensor connector. Measure resistance between knock sensor connector terminal and ground. If about 560,000 ohms are present, go to next step. If about 560,000 ohms are not present, replace knock sensor.
- Disconnect ECU and knock sensor connectors. Measure resistance between ECU connector B56, terminal No. 5 and knock sensor connector. Zero ohms should be present. Measure resistance between knock sensor connector terminal and ground. At least one megohm should be present. If resistances are not to specification, repair harness or connector. If resistances are to specification, check ECU terminals for poor contact or replace ECU.
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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.