Toyota Supra 1990 Manual page 199

EFI SYSTEM - Diagnosis System
FI-25
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0
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EFI 15A
FI3826
CANCELLING OUT DIAGNOSTIC CODE
1. After repairing of the trouble, the diagnostic code retained
in memory by the ECU must be cancelled out by removing
the EFI fuse 15A for 30 seconds or more, depending on
ambient temperature (the lower the temperature, the longer
the fuse must be left out) with the ignition switch off.
HINT:
• Cancellation can also be done by removing the battery
negative (-) terminal, but in this case other memory sys-
tems (radio ETR, clock etc.) will also be cancelled out.
• If the diagnostic code is not cancelled out, it will be re-
tained 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, road test the vehicle to confirm that the
"normal" code is now displayed by the "CHECK ENGINE"
warning light.
If the same diagnostic code is still indicated, it means that
the trouble area has not been repaired thoroughly.
DIAGNOSIS INDICATION
1. When 2 or more codes are indicated, the lowest number
(code) will appear first.
2. All detected diagnostic codes, except code Nos.51 and 53,
will be retained in memory by the ECU from the time of
detection until cancellation.
3. Once the malfunction is cleared, the "CHECK ENGINE"
warning light on the instrument panel will go out but the
diagnostic code(s) remains stored in ECU memory (except
for code Nos.51 and 53).