Toyota T100 1996 Service Manual page 393

TOYOTA Hand−Held Tester
DLC 3
1996 TOYOTA T100 (RM449U)
DIAGNOSTICS − ENGINE (5VZ−FE)
PRE−CHECK
1. DIAGNOSIS SYSTEM
(a) Description
When troubleshooting OBD II vehicles, the only dif-
S
ference from the usual troubleshooting procedure
is that you connect to the vehicle the OBD II scan
tool complying with SAE J1978 or TOYOTA hand−
held tester, and read off various data output from
the vehicle's ECM.
FI0534
OBD II regulations require that the vehicle's on−
S
board computer lights up the Malfunction Indicator
Lamp (MIL) on the instrument panel when the com-
puter detects a malfunction in the computer itself or
in drive system components which affect vehicle
emissions. In addition to the MIL lighting up when
a malfunction is detected, the applicable Diagnostic
Trouble Codes (DTCs) prescribed by SAE J2012
are recorded in the ECM memory (See page
DI−140).
If the malfunction does not reoccur in 3 trips, the MIL goes off
but the DTCs remain recorded in the ECM memory.
To check the DTCs, connect the OBD II scan tool or
S
TOYOTA hand−held tester to the Data Link Con-
nector 3 (DLC3) on the vehicle. The OBD II scan
tool or TOYOTA hand−held tester also enables you
to erase the DTCs and check freezed frame data
and various forms of engine data (For operating
instructions, see the OBD II scan tool's instruction
book.).
DTCs include SAE controlled codes and manufac-
S
FI7231
turer controlled codes. SAE controlled codes must
be set as prescribed by the SAE, while manufactur-
er controlled codes can be set freely by the
manufacturer within the prescribed limits (See DTC
chart on page DI−140).
DI−129
DI0UB−02