Lexus ES300 (2002 year). Manual - part 380

A54404

EPA2

EPA

E6

A54384

EPA

EPA2

05-126

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

279

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

3

CHECK HARNESS AND CONNECTOR(ECM  -  ACCELERATOR POSITION
SENSOR)

(a)

Disconnect the ECM E6 connector.

(b)

Check the continuity of the accelerator position sensor
and ECM.
Standard: Continuity

(c)

Check the continuity of the EPA, EPA2 of the accelerator
position sensor and the body ground.
Standard: No continuity

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

REPLACE ACCELERATOR PEDAL ASSY

A54292

Throttle body assy
(Throttle Motor)

2

1

B

W

ECM

3

2

17

M+

M-

E8

(Shielded)

E8

E8

GE01

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-127

280

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

DTC

P1125

THROTTLE CONTROL MOTOR CIRCUIT
MALFUNCTION

CIRCUIT DESCRIPTION

Throttle motor is operated by the ECM and it opens and closes the throttle valve.
The opening angle of the throttle valve is detected by the throttle position sensor which is mounted on the
throttle body and it provides feedback to the ECM to control the throttle motor in order to control the throttle
valve opening angle properly in response to driving condition.
If this DTC is stored, the ECM shuts down the power for the throttle motor, and the throttle valve is fully closed
by the return spring.

DTC No.

DTC Detection Condition

Trouble Area

Conditions (a) and (b) continue for 2.0 seconds:

(a) Throttle control motor output duty 

 80 %

(b) Throttle control motor current < 0.5 A

Open or short in throttle control motor circuit

P1125

Throttle control motor current 

 16 A

Throttle body assy (Throttle motor)

ECM

Condition (a) continues for 0.6 seconds:

(a) Throttle control motor current 

 high

ECM

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records the engine
conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the
vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc.
at the time of the malfunction.

056HA-01

A03403

A03404

A58429

M+ Signal Waveform

5V/

Division

GND

1 m sec./Division

M-  Signal Waveform

GND

5V/

Division

1 m sec./Division

A57007

05-128

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

281

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

1

INSPECT THROTTLE BODY ASSY(THROTTLE CONTROL MOTOR CIRCUIT)

(a)

Check the waveform between E8 ECM terminals M+ or
M-  and E1 when the engine is idling.

HINT:
The waveform frequency changes depending on the throttle
opening.

OK

CHECK AND REPLACE ECM

NG

2

INSPECT THROTTLE BODY ASSY(THROTTLE CONTROL MOTOR)

(a)

Disconnect the throttle control motor connector.

(b)

Using an ohmmeter, measure the motor resistance be-
tween terminals 1 (M-) and 2 (M+).
Motor resistance: 0.3 - 100 

Ω

 at 20

°

C (68

°

F)

NG

REPLACE THROTTLE BODY ASSY

OK

A54408

M+

M-

E8

A51984

A52933

M-

M+

-

DIAGNOSTICS

SFI SYSTEM (1MZ-FE)

05-129

282

2002 LEXUS ES300 REPAIR MANUAL   (RM911U)

3

CHECK HARNESS AND CONNECTOR(ECM - THROTTLE CONTROL MOTOR)

(a)

Disconnect the ECM E8 connector.

(b)

Check the continuity of the throttle control motor and
ECM.
Standard: Continuity

NG

REPAIR OR REPLACE HARNESS AND
CONNECTOR

OK

CHECK AND REPLACE ECM