Once a malfunction has been established (two trip detection logic where applicable) the MIL will illuminate and remain illuminated even if the condition is intermittent. The MIL will remain on after subsequent restarts even if the malfunction condition is no longer present. The OBD-II system can only extinguish the MIL if the malfunction does not reoccur during three subsequent sequential trip cycles.
The OBD-II system can only erase a stored DTC if the malfunction is not detected during forty sequential trip cycles. Toyota systems do not erase the code, but rather place a flag on any code which does not reoccur during 40 subsequent trip cycles.
DTCs can be erased using the generic scan tool or by removing power from the ECM BATT terminal.
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