Lexus RX300 (MCU15). Service manual — part 214

DI–88

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DIAGNOSTICS

ENGINE

LEXUS RX300 (RM785E)

4

Check resistance of A/F sensor heater (See page FI–67).

NG

Replace A/F sensor.

OK

5

Check air induction system (See page FI–1).

NG

Repair or replace.

OK

6

Check fuel pressure (See page FI–5).

NG

Check and repair fuel pump, pressure regulator,
fuel pipe line and filter (See page FI–5).

OK

7

Check injector injection (See page FI–22).

NG

Replace injector.

OK

Replace A/F sensor.

8

Perform confirmation driving pattern (See page DI–85).

Go

–

DIAGNOSTICS

ENGINE

DI–89

LEXUS RX300 (RM785E)

9

Is there DTC P1130 or P1150 being output again?

YES

Check and replace engine ECU
(See page IN–32).

NO

10

Did vehicle runs out of fuel in past?

NO

Check for intermittent problems
(See page DI–3).

YES

DTC P1130 or P1150 is caused by running out
of fuel.

DI–90

–

DIAGNOSTICS

ENGINE

LEXUS RX300 (RM785E)

DTC

P1133

A/F Sensor Circuit Response Malfunction
(Bank 1 Sensor 1)

DTC

P1153

A/F Sensor Circuit Response Malfunction
(Bank 2 Sensor 1)

CIRCUIT DESCRIPTION

Refer to DTC P0125 on page DI–42.

DTC No.

DTC Detecting Condition

Trouble Area

P1133

P1153

After engine is warmed up, and during vehicle driving at engine

speed 1,400 rpm or more and vehicle speed 60 km/h (38 mph)

or more, if the response characteristic of A/F sensor becomes

deteriorated (2 trip detection logic)

S Open or short in A/F sensor circuit

S A/F sensor

S Air induction system

S Fuel pressure

S Injector

S Engine ECU

WIRING DIAGRAM

Refer to DTC P0125 on page DI–42.

INSPECTION PROCEDURE

HINT:
Read freeze frame data using hand–held tester or OBD scan tool. Because freeze frame records the engine
conditions when the 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.

1

Are there any other codes (besides DTC P1133, P1153) being output?

YES

Go to relevant DTC chart (See page DI–14).

NO

2

Connect OBD scan tool or hand–held tester, and read value for voltage output of
A/F sensor.

PREPARATION:
(a)

Connect the OBD scan tool or hand–held tester to the DLC3.

(b)

Warm up the A/F sensor with the engine speed at 2,500 rpm for approx. 90 sec.

CHECK:
Read the voltage of the A/F sensor on the screen of the OBD scan tool or hand–held tester when you perform
all the following conditions.

DI2H8–06

–

DIAGNOSTICS

ENGINE

DI–91

LEXUS RX300 (RM785E)

HINT:
The voltage of the AFR+ or AFL+ terminal of the engine ECU is fixed at 3.3 V and the voltage of the AFR–
or AFL– terminal is fixed at 3.0 V. Therefore, it is impossible to check the A/F sensor output voltage at the
terminals (AFR+, AFL+/AFR–, AFL–) of the engine ECU.
OK:

Condition

A/F Sensor Voltage value

Engine idling

Engine racing

S Not remains at 3.30 V (0.660 V*)

S Not remains at 3 8 V (0 76 V*) or more

Driving at engine speed 1,500 rpm or more and vehicle

speed 40 km/h (25 mph) or more, and operate throttle valve

open and close

S Not remains at 3.8 V (0.76 V*) or more

S Not remains at 2.8 V (0.56 V*) or less

*: When you use the OBD scan tool (excluding hand–held tester)

HINT:

S

During fuel enrichment, there is a case that the output voltage of the A/F sensor is below 2.8 V (0.56
V*), it is normal.

S

During fuel cut, there is a case that the output voltage of the A/F sensor is above 3.8 V (0.76 V*), it
is normal.

S

If the output voltage of the A/F sensor remains at 3.30 V (0.660 V*) even after performing all the above
conditions, the A/F sensor circuit may be open.

S

If the output voltage of the A/F sensor remains at 3.8 V (0.76V*) or more, or 2.8 V (0.56 V*) or less even
after performing all the above conditions, the A/F sensor circuit may be short.

*: When you use the OBD scan tool (excluding hand–held tester).

OK

Go to step 9.

NG

3

Check for open and short in harness and connector between engine ECU and
A/F sensor (See page IN–32).

NG

Repair or replace harness or connector.

OK

4

Check resistance of A/F sensor heater (See page FI–67).

NG

Replace A/F sensor.

OK