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Lexus Code Retrieval
Accessing Diagnostic Trouble Codes
The check engine warning light will come on when the ignition switch is
turned On and the engine is not running. When the engine is started, the
check engine warning light should go off. If light remains on, the
self-diagnosis system has detected a mat-function or abnormality in the
system. Access trouble codes as follows:
- Certain conditions must be met before accessing codes, they are as
follows: Battery voltage must be 11 volts or more. Throttle valve must
be fully closed. Transmission must be in Neutral position. All
accessories must be turned Off.
- On models less OBD II, turn ignition to On, then use a jumper wire to
connect terminals TE1 and El of the data link connector, located under
the left hand side of the instrument panel. Codes are indicated by the
number of flashes of the check engine warning light. On models with OBD
II, prepare scan tool to SAE J 1978, then connect to data link connector
(DLC) No. 3 in fuse panel on instrument panel lower left-hand side. Turn
ignition and scan tool to On, and write down any codes and
"freeze-frame data" that appear.
Diagnostic Trouble Code
Interpretation
Normal system operation. Engine light will alternately blink On and Off
two times per second. If the ECU has detected a system malfunction, the
check engine light will blink every .5 second. The first number of blinks
will equal the first digit of a two digit diagnostic trouble code and after
a 1.5 second pause, the second number of blinks will equal the second digit
of same diagnostic trouble code. If there are two or more DTC's, there will
be a 2.5 second pause between each. After all DTC's have been output there
will be a 4.5 second pause and all DTC's will be repeated as long as the
terminals TE1 and El of the data link connector are connected. In the event
of two or more DTC's, indication will begin from smaller numbered code and
continue in order to the larger. After all DTC have been recorded, remove
jumper wire.
Clearing Diagnostic Trouble Codes
After service, the diagnostic trouble code or DTC's retained in the ECU
memory must be cleared by remove the EFI fuse for approximately 10 seconds
or more, depending on ambient temperature (the lower the temperature, the
longer the fuse must be left out) with the ignition switch off. The OBD II
scan tool has a feature to clear DTC's. Refer to the manufacturer's manual
for procedures. DTC cancellation can also be done by removing the battery
ground cable, but keep in mind that other memory systems (clock) will also
be cancelled out. If the diagnostic trouble code is not cancelled out, it
will be retained by the ECU and appear along with a new DTC in the event of
future trouble. If it is necessary to work on engine components requiring
removal of the battery ground cable, ensure no DTC's are stored. After
cancellation, road test the vehicle to check that a normal operating code is
now obtained on the check engine warning light. If the same diagnostic
trouble code appears, the trouble has not been corrected thoroughly.
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