05ESO-05
FI0534
A80020
Hand-held Tester
DLC3
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-35
225 Author: Date:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DIAGNOSIS SYSTEM
1. DESCRIPTION
When troubleshooting On-Board Diagnostic (OBD II) ve-
hicles, the vehicle must be connected to the OBD II scan
tool (in compliance with SAE J1978) or the hand-held
tester. Various data output from the vehicle's ECM can
then be read.
OBD II regulations require that the vehicle's on-board
computer illuminates the Malfunction Indicator Lamp
(MIL) on the instrument panel when the computer detects
a malfunction in: 1) the emission control system/compo-
nents, or 2) the powertrain control components (which af-
fect vehicle emissions), or 3) the computer. In addition,
the applicable Diagnostic Trouble Codes (DTCs) pre-
scribed by SAE J2012 are recorded in the ECM memory
(see page 05-48).
If the malfunction does not reoccur in 3 consecutive trips, the
MIL turns off automatically but the DTCs remain recorded in the
ECM memory.
To check DTCs, connect the hand-held tester or OBD II
scan tool to the Data Link Connector 3 (DLC3) of the ve-
hicle. The hand-held tester or OBD II scan tool also en-
ables you to erase the DTC and check the freeze frame
data and various forms of engine data (see the instruction
manual for the OBD II scan tool or the hand-held tester).
The DTC includes SAE controlled codes and manufactur-
er controlled codes. SAE controlled codes must be set ac-
cording to the SAE, while manufacturer controlled codes
can be set by a manufacturer with certain restrictions (see
the DTC chart on page 05-48).
The diagnosis system operates in ºnormal modeº during
normal vehicle use. In ºnormal modeº, 2 trip detection log-
ic* is used to ensure accurate detection of malfunctions.
A ºcheck modeº is also available to technicians as an op-
tion. In ºcheck modeº, 1 trip detection logic is used for sim-
ulating malfunction symptoms and increasing the sys-
tem's ability to detect malfunctions, including intermittent
malfunctions (hand-held tester only) (see page 05-40).
