Lexus RX300 (MCU15). Manual - part 213

DI–84

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DIAGNOSTICS

ENGINE

LEXUS RX300   (RM785E)

3

Check operation of the ISC valve (See page FI–44).

NG

Repair or replace ISC valve.

OK

4

Check the blockage of ISC valve and the passage to bypass the throttle valve.

NG

Repair or replace ISC valve.

OK

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

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DIAGNOSTICS

ENGINE

DI–85

LEXUS RX300   (RM785E)

DTC

P1130

A/F Sensor Circuit Range/Performance Mal-
function (Bank 1 Sensor 1)

DTC

P1150

A/F Sensor Circuit Range/Performance Mal-
function (Bank 2 Sensor 1)

CIRCUIT DESCRIPTION

Refer to DTC P0125 on page DI–42.

DTC No.

DTC Detecting Condition

Trouble Area

Voltage output* of A/F sensor remains at 3.8 V or more, or 2.8

V or less, during engine running after the engine is warmed up

(2 trip detection logic)

*: Output value changes at inside of engine ECU only

S Open or short in A/F sensor circuit

S A/F sensor

P1130

P1150

Voltage output* of A/F sensor does not change from 3.30 V,

during engine running after the engine is warmed up (2 trip

detection logic)

*: Output value changes at the inside of engine ECU only

S Air induction system

S Fuel pressure

S Injector

S Engine ECU

Open or short in A/F sensor circuit (2 trip detection logic)

HINT:

S

After confirming DTC P1130, use the OBD scan tool or hand-held tester to confirm voltage output of
A/F sensor (AFS B1 S1/O2S B1 S1) from the CURRENT DATA.

S

The A/F sensor's output voltage and the short-term fuel trim value can be read using the OBD scan
tool or hand-held tester.

S

The ECM controls the voltage of the AFR+, AFL+, AFR- and AFL- terminals of the engine ECU to
the fixed voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without the OBD
scan tool or hand–held tester.

S

OBD scan tool (excluding hand-held tester) displays the one fifth of the A/F sensor output voltage
which is displayed onthe hand-held tester.

WIRING DIAGRAM

Refer to DTC P0125 on page DI–42.

DI2H7–06

A00364

Vehicle Speed

60 – 120 km/h

(38 – 75 mph)

Idling

IG SW OFF

3 – 5 min.

Time

(a)(b)

(c)

(d)

DI–86

–

DIAGNOSTICS

ENGINE

LEXUS RX300   (RM785E)

CONFIRMATION DRIVING PATTERN

(a)

Connect the hand–held tester to the DLC3.

(b)

Switch the hand–held tester from the normal mode to the check mode (See page DI–3).

(c)

Start the engine and warm it up with all the accessory switches OFF.

(d)

Drive the vehicle at 60 – 120 km/h (38 – 75 mph) and engine speed at 1,400 – 3,200 rpm for 3 – 5 min.

HINT:
If a malfunction exists, the check engine warning light will light up during step (d).
NOTICE:
If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.
If you do not have a hand–held tester, turn the ignition switch OFF after performing steps (c) and (d),
then perform steps (c) and (d) again.

INSPECTION PROCEDURE

HINT:

S

If DTC P1130 is displayed, check Bank 1 Sensor 1 circuit.

S

If DTC P1150 is displayed, check Bank 2 Sensor 1 circuit.

S

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 P1130, P1150) being output?

YES

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

NO

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DIAGNOSTICS

ENGINE

DI–87

LEXUS RX300   (RM785E)

2

Check output voltage 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 value of the A/F sensor on the screen of OBD scan tool or hand–held tester when you
perform all the following conditions.
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 OBD II scan tool (excluding TOYOTA 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 normally.

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 (0.76 V*) 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