Lexus ES300 (1997 year). Service manual — part 307

N09214

DLC3

DI–4

–

DIAGNOSTICS

ENGINE

156

1997 LEXUS ES300 (RM511U)

Freeze frame data:
Freeze frame data records the engine condition when a
misfire (DTC P0300

∼

P0306) or fuel trim malfunction

(DTC P0171, P0172) or other malfunction (first malfunc-
tion only), is detected.
Because freeze frame data records the engine conditions
(fuel system, calculator load, engine coolant tempera-
ture, fuel trim, engine speed, vehicle speed, etc.) when
the malfunction is detected, when troubleshooting it is
useful for determining whether the vehicle was running or
stopped, the engine warmed up or not, the air–fuel ratio
lean or rich, etc. at the time of the malfunction.
Priorities for troubleshooting:
If troubleshooting priorities for multiple DTC are given in
the applicable DTC chart, these should be followed.
If no instructions are given troubleshoot DTC according
to the following priorities.
(1)

DTC other than fuel trim malfunction (DTC P0171,
P0172), EGR (DTC P0401, P0402) and misfire
(DTC P0300

∼

P0306).

(2)

Fuel trim malfunction (DTC P0171, P0172) and
EGR (DTC P0401, P0402).

(3)

Misfire (DTC P0300

∼

P0306).

(b)

Check the DLC3.
The vehicle’s ECM uses ISO 9141–2 for communication.
The terminal arrangement of DLC3 complies with SAE
J1962 and matches the ISO 9141–2 format.

Terminal No.

Connection / Voltage or Resistance

Condition

7

Bus

Line / Pulse generation

During transmission

4

Chassis Ground /

↔

Body Ground 1

Ω

or less

Always

5

Signal Ground /

↔

Body Ground 1

Ω

or less

Always

16

Battery Positive /

↔

Body Ground 9

∼

14 V

Always

HINT:If your display shows ”UNABLE TO CONNECT TO VE-
HICLE” when you have connected the cable of the OBD II scan
tool or LEXUS hand–held tester to DLC3, turned the ignition
switch ON and operated the scan tool, there is a problem on the
vehicle side or tool side.

(1)

If communication is normal when the tool is con-
nected to another vehicle, inspect DLC3 on the orig-
inal vehicle.

(2)

If communication is still not possible when the tool
is connected to another vehicle, the problem is
probably in the tool itself, so consult the Service De-
partment listed in the tool’s instruction manual.

S05349

–

DIAGNOSTICS

ENGINE

DI–5

157

1997 LEXUS ES300 (RM511U)

2.

INSPECT DIAGNOSIS (Normal Mode)

(a)

Check the MIL.
(1)

The MIL comes on when the ignition switch is turned
ON and the engine is not running.

HINT:If the MIL does not light up, troubleshoot the combination
meter (See page

BE–87

).

(2)

When the engine started, the MIL should go off. If
the lamp remains on, the diagnosis system has de-
tected a malfunction or abnormality in the system.

(b)

Check the DTC.

NOTICE:NOTICE (LEXUS hand–held tester only): When the
diagnosis system is switched from normal mode to check
mode, it erases all DTC and freezed frame data recorded
in normal mode. So before switching modes, always check
the DTC and freezed frame data, and note them down.

(1)

Prepare the OBD II scan tool (complying with SAE
J 1978) or LEXUS hand–held tester.

(2)

Connect the OBD II scan tool or LEXUS hand–held
tester to DLC3 at the lower center of the instrument
panel.

(3)

Turn the ignition switch ON and push the OBD II
scan tool or LEXUS hand–held tester switch ON.

(4)

Use the OBD II scan tool or LEXUS hand–held tes-
ter to check the DTC and freezed frame data, note
them down (For operating instructions, see the
OBD II scan tool’s instruction book.).

(5)

See page

DI–14

to confirm the details of the DTC.

NOTICE:When simulating symptoms with an OBD II scan
tool (excluding LEXUS hand–held tester) to check the DTC,
use normal mode. For code on the DTC chart subject to ”2
trip detection logic”, turn the ignition switch OFF after the
symptom is simulated the first time. Then repeat the simu-
lation process again. When the problem has been simu-
lated twice, the MIL lights up and the DTC are recorded in
the ECM.

FI3605

Flashing

ON

OFF

0.13 Seconds

DI–6

–

DIAGNOSTICS

ENGINE

158

1997 LEXUS ES300 (RM511U)

3.

INSPECT DIAGNOSIS (Check Mode)

LEXUS hand–held tester only:
Compared to the normal mode, the check mode has an in-
creased sensitivity to detect malfunctions.
Furthermore, the same diagnostic items which are detected in
the normal mode can also be detected in the check mode.
(a)

Check the DTC.
(1)

Initial conditions.

Battery positive voltage 11V or more

Throttle valve fully closed

Transmission in ”P” or ”N” position

Air conditioning switched OFF

(2)

Turn ignition switch OFF.

(3)

Prepare the LEXUS hand–held tester.

(4)

Connect the LEXUS hand–held tester to DLC3 at
the lower center of the instrument panel.

(5)

Turn the ignition switch ON and push the LEXUS
hand–held tester switch ON.

(6)

Switch the LEXUS hand–held tester normal mode
to check mode (Check that the MIL flashes.).

(7)

Start the engine (The MIL goes out after the engine
start.).

(8)

Simulate the conditions of the malfunction de-
scribed by the customer.

NOTICE:Leave the ignition switch ON until you have
checked the DTC, etc.

(9)

After simulating the malfunction conditions, use the
LEXUS hand–held tester diagnosis selector to
check the DTC and freezed frame data, etc.

HINT:Take care not to turn the ignition switch OFF. Turning the
ignition switch OFF switches the diagnosis system from check
mode to normal mode, so all DTC, etc. are erased.

(10) After checking the DTC, inspect the applicable cir-

cuit.

(b)

Clear the DTC.

The following actions will erase the DTC and freezed frame
data.

(1)

Operating the OBD II scan tool (complying with SAE
J1978) or LEXUS hand–held tester to erase the
codes (See the OBD II scan tool’s instruction book
for operating instructions.).

(2)

Disconnecting the battery terminals or EFI fuse.

NOTICE:If the LEXUS hand–held tester switches the ECM
from normal mode to check mode or vice–versa, or if the
ignition switch is turned from ON to ACC or OFF during
check mode, the DTC and freezed frame data will be
erased.

–

DIAGNOSTICS

ENGINE

DI–7

159

1997 LEXUS ES300 (RM511U)

4.

FAIL–SAFE CHART

If any of the following codes is recorded, the ECM enters fail–safe mode.

DTC No.

Fail–Safe Operation

Fail–Safe Deactivation Conditions

P0100

Ignition timing fixed at 10

° BTDC

Returned to normal condition

P0110

Intake air temp. is fixed at 20

°

C (68

°

F)

Returned to normal condition

P0115

Engine coolant temp. is fixed at 80

°C (176°F)

Returned to normal condition

P0120

VTA is fixed at 0

°

The following condition must be repeated at least 2 times

consecutively

0.1 V

VTA

0.95 V

P0135

P0141

P0155

The heater circuit in witch an abnormality is detected is

turned off

Ignition switch OFF

P0325

P0330

Max. timing retardation

Ignition switch OFF

P1300

Fuel cut

Returned to normal condition

5.

CHECK FOR INTERMITTENT PROBLEMS

LEXUS HAND–HELD TESTER only:
By putting the vehicle’s ECM in check mode, 1 trip detection logic is possible instead of 2 trip detection logic
and sensitivity to detect open circuits is increased. This makes it easier to detect intermittent problems.
(a)

Clear the DTC (See page

DI–3

).

(b)

Set the check mode (See page

DI–3

).

(c)

Perform a simulation test (See page

IN–17

).

(d)

Check the connector and terminal (See page

IN–27

).

(e)

Handle the connector (See page

IN–27

).

6.

BASIC INSPECTION

When the malfunction code is not confirmed in the DTC check, troubleshooting should be performed in the
order for all possible circuits to be considered as the causes of the problems. In many cases, by carrying
out the basic engine check shown in the following flow chart, the location causing the problem can be found
quickly and efficiently. Therefore, use of this check is essential in engine troubleshooting.

1

Is battery positive voltage 11 V or more when engine is stopped ?

NO

Charge or replace battery.

YES

2

Is engine cranked ?

NO

Proceed to page

ST–18

and continue to

troubleshoot.

YES