Trouble codes 12 and 28

1992 TOYOTA CAMRY
226,700 MILES • 6 CYL • FWD • AUTOMATIC
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CZEVELY
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I have found that trouble codes 12 and 28 flashed when I diagnosed my check engine light. I know from looking on line that trouble code 12 is the knock sensor signal and code 28 is the No. 2 Oxygen sensor signal. What I need to know is what specifically might need to be repaired based on this information?
Jun 8, 2010 at 12:00 PM
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KHLOW2008
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Hi CZevely,

Thank you for the donation.

Code 12 is for RPM signal and not the knock sensor which should be either Code 52 or 55.

It could be due to a faulty distributor or its circuits, starter circuits or a bad ECU. There are no diagnostic procedures for this code.

As to Code 28, it is a fault with the main O2 sensor and it could either be th right or left bank as pre-OBD II trouble codes are not specific.

I have emailed the diagnostic files to you . They explain how to go about cheking/repairing the problem.
Jun 9, 2010 at 8:25 AM