Cancelling Diagnostic Code - Toyota MR2 1988 Repair Manual

EFI SYSTEM - Diagnosis System
Fl-23
CANCELLING DIAGNOSTIC CODE
1.
After repair of the trouble area, the diagnosis code
retained in memory by the ECU must be cancelled out by
removing the fuse AM
2
(7.5A). located in the engine com-
partment No. 2 relay box, for 1 0 seconds or more,
depending on ambient temperature (the lower the tem-
perature, the longer the fuse must be left out) with the
ignition switch off.
NOTE:
• Cancellation can also be done by removing the battery
negative (-) terminal, but in this case, other memory
systems (clock, etc.) will also be cancelled out.
• If the diagnosis code is not cancelled out, it will be
retained by the ECU and appear along with a new code
in the event of future trouble.
• If it is necessary to work on engine components requir-
ing removal of the battery terminal, a check must first
be made to see if a diagnostic code has been recorded.
2. After cancellation, perform a road test to confirm that a
"normal" code is now read on the "CHECK ENGINE"
warning light.
If the same diagnosis code appears, it indicates that the
trouble area has not been repaired thoroughly.