Diagnostic Trouble Codes Cancellation; 2 Trip Detection Logic - Toyota 22R-E Service Manual

EG1–112
ENGINE – MFI SYSTEM
(c) (2 trip detection logic)
The diagnostic trouble codes 21, 25, 26, 27 and 71
use "2 trip detection logic". With this logic, when a
logic malfunction is first detected, the malfunction is
temporarily stored in the ECM memory. If the same
case is detected again during the second drive test,
this second detection causes the Malfunction Indica–
tor Lamp to light up.
The 2 trip repeats the same mode a 2nd time. (How–
ever, the IG SW must be turned OFF between the 1st
time and 2nd time).
5. After the diagnostic check, remove SST.
DIAGNOSTIC TROUBLE CODES
CANCELLATION
1. After repair of the trouble area, the diagnostic tro–
uble code retained in memory by the ECM must be
canceled out by removing the EFI fuse (15A) 30
seconds or more, depending on ambient tempera–
ture (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
systems (radio ETR, etc.) will also be canceled out.
If the diagnostic trouble code is not canceled out, it
will be retained by the ECM and appear along with a
new code in the event of future trouble.
If it is necessary to work on engine components req–
uiring removal of the battery terminal, a check must
first be made to see if a diagnostic trouble code has
been recorded.
2. After cancellation, road test the vehicle, if neces–
sary, confirm that a 'normal' code is now read on
the Malfunction Indicator Lamp.
If the same diagnostic trouble code appears, it in–
dicates that the trouble area has not been repaired
thoroughly.