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 28: Knock Sensor No. 2
NOTE:
Refer to illustration for ECU connector and terminal identification. See Figure
.
- Turn ignition switch to ON position. Using a DVOM, check voltage between ECU connector B61, terminal No. 6 and ground. Voltage should be 3-4 volts. If voltage is not as specified, go to next step. If voltage is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.
- Remove collector and disconnect knock sensor connector, located on side of block. Using an ohmmeter, check resistance between knock sensor terminal and ground. Resistance should be about 560,000 ohms. If resistance is as specified, repair circuit between ECU and knock sensor. If resistance is not as specified, replace knock sensor.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.