Trouble codes 12 and 28

1992 TOYOTA CAMRY
226,700 MILES • 6 CYL • FWD • AUTOMATIC
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CZEVELY
  • MEMBER
  • 1 POST
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 5:00 AM
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KHLOW2008
  • ✓Experienced Mechanic
  • 41,812 POSTS
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 1:25 AM
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