The code PO136 means: O2 Sensor Circuit Malfunction (Bank I Sensor 2) Its the o2 sensor behind your CAT Converter. I would inspect the wiring first and make sure its secure before I replace the sensor.
i bought use tercel 99 its manual trans 152000km run fin for 2 day then engine light turn on still...
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i bought use tercel 99 its manual trans 152000km run fin for 2 day then engine light turn on still run good it just use mor gas