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2003 Mazda Miata P0012 Code: Camshaft Position Timing Over Retarded Bank 1 - Diagnosis and Fixes

Model: Mazda Miata Fault Code: P0012 Posted: 2019-03-20 06:52

I own a 2003 Mazda Miata MX-5 with 75,000 miles. After having my timing belt replaced at the dealer, the check engine light activated approximately 150 miles later. The diagnostic code displayed is P0012: 'Camshaft Position - Timing Over-Retarded Bank 1'. I have already replaced the oil control valve (OCV), cam position sensor, fuel pump, and fuel filter. Today, I performed an engine flush using BG EPR as recommended by Mazda's service report. Has anyone else experienced this P0012 issue on a 2003 Mazda Miata? If so, what steps did you take to resolve it? Was the problem related to the timing belt installation or a faulty sensor/valve? I'm particularly interested in whether the issue was due to improper OCV function or deeper engine system contamination. Any insights would be greatly appreciated. Note: Mazda's official guidance includes recommending an engine flush as part of the troubleshooting process for this code.

Related fault codes
P0012
Comments (8)
Anonymous 2019-03-20 11:44

I had my timing belt replaced at the dealer and about 150 miles later, the check engine light came on. Did you return to the dealer? If so, what was their diagnosis? I don't have a fix other than considering oil pressure issues. Was the OCV filter cleaned or replaced? Read more: https://example.com/18192

Anonymous 2019-03-20 12:14

The dealer diagnosed it as an issue with the oil control valve (OCV). I replaced the OCV, but the same problem returned. Mazda specifically recommends engine flushing in such cases.

Anonymous 2019-03-20 12:42

I believe the dealer may have made a mistake during the timing belt installation and possibly misdiagnosed the OCV issue. Has your OCV filter been checked? It should be re-inspected after the engine flush procedure.

Anonymous 2019-03-20 14:39

The dealer inspected and rechecked the timing, then reset it. They suggested the OCV might be at fault. However, if the code returns, it could point to a problem with the Powertrain Control Module (PCM).

Anonymous 2019-03-20 15:24

Thanks for sharing your update — please let us know what solution worked for you.

Anonymous 2019-03-28 12:45

I completed an engine flush with BG EPR and have driven the car over 330 miles. The P0012 code has not reappeared, suggesting that the VVT phaser system may have been effectively cleaned.

Anonymous 2019-03-28 13:27

Thanks for the follow-up. It seems likely that the engine flush cleared any buildup in the VVT system, which may have been causing the timing misalignment.

Anonymous 2019-03-28 13:42

I replaced both the OCV solenoid and cam position sensor, cleaned the strainer before the flush, and followed Mazda's recommended procedure. The engine flush appears to have effectively cleaned the VVT system — this aligns with their guidance for P0012 issues.