Inspection Procedure

WARNING: This page is about a different car, the 2008 Toyota RAV4. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

Techstream only:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor function provided in the Active Test. The Control the Injection Volume for A/F Sensor function can help to determine whether the Air-fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F Sensor operation using Techstream.

Connect Techstream to the DLC3.
Start the engine and turn the tester ON.
Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
On the tester, select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
Perform the Control the Injection Volume for A/F Sensor operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).
Monitor the output voltages of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2) displayed on the tester.

HINT:

The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.
The sensors react in accordance with increases and decreases in the fuel injection volume.

Standard

INJECTION VOLUMES AND VOLTAGE SPECIFICATION

Tester Display (Sensor)	Injection Volume	Status	Voltages
AFS B1 S1 (A/F)	+25 %	Rich	Less than 3.0
AFS B1 S1 (A/F)	-12.5 %	Lean	More than 3.35
O2S B1 S2 (HO2)	+25 %	Rich	More than 0.5
O2S B1 S2 (HO2)	-12.5 %	Lean	Less than 0.4

NOTE: The A/F sensor has an output delay of a few seconds and the HO2 sensor (sensor 2) output has a maximum output delay of approximately of 20 seconds.

A/F SENSOR AND HO2 SENSOR VOLTAGE SPECIFICATION

Case	Air Fuel Ratio Sensor (Sensor 1) Output Voltage	Heated Oxygen Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Areas
1	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
2	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor circuit
3	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Heated oxygen sensor Heated oxygen sensor heater Heated oxygen sensor circuit
4	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Fuel pressure Gas leakage from exhaust system (Air fuel ratio extremely lean or rich)

Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors. To display the graph, select the following menu items on the tester: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2 then press the graph button on the Data List view.

Result

RESULT REFERENCE

Result	Proceed To
Case 1	C
Case 2	B
Case 3	A

Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.

To display the graph, select the following menu items on the tester: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2 then press the graph button on the Data List view.

HINT:

Read freeze frame data using Techstream. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.
A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO P2195 OR P2196)

Connect Techstream to the DLC3.
Turn the ignition switch ON.
Turn the tester ON.
Select the following menu items: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

Read DTCs.

Result

RESULT REFERENCE

Display (DTC Output)	Proceed To
P2195 or P2196	A
P2195 or P2196 and other DTCs	B

HINT:

If any DTCs relating to the A/F sensor (DTCs for the A/F sensor heater or A/F sensor admittance) are output, troubleshoot those DTCs first.

B: GO TO DTC CHART

A: Go to Next Step

READ VALUE USING TECHSTREAM (TEST VALUE OF A/F SENSOR)

Connect Techstream to the DLC3.
Turn the ignition switch ON and turn the tester ON.
Clear DTCs (see DTC CHECK / CLEAR ).
Drive the vehicle in accordance with the drive pattern described in the CONFIRMATION DRIVING PATTERN.
Select the following menu items: Powertrain / Engine and ECT / Monitor / O2 Sensor / Status 2.
Check that the status of O2 Sensor is Complete. If the status is still Incomplete, drive the vehicle according to the driving pattern again.
HINT:
- Complete indicates that the component is functioning normally.
- Incomplete indicates that the component is malfunctioning.
Select the following menu items: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details / RANG B1 S1.

Check the test value of the A/F sensor output current during fuel-cut.

Result

RESULT REFERENCE

Test Value	Proceed To
Within normal range (1.0 mA or more, and less than 3.6 mA)	A
Outside normal range (Less than 1.0 mA, or 3.6 mA or more)	B

B: Go to step 12

A: Go to Next Step

READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF A/F SENSOR)

Connect Techstream to the DLC3.
Start the engine.
Turn the tester ON.
Warm up the A/F sensor at an engine speed of 2,500 rpm for 90 seconds.
On the tester, select the following menu items: Powertrain / Engine and ECT / Data List / AFS B1 S1 and Engine Speed, then press the Record button.

Check the A/F sensor voltage 3 times, when the engine is in each of the following conditions:

While idling (check for at least 30 seconds)
At an engine speed of approximately 2,500 rpm (without any sudden changes in engine speed)

Raise the engine speed to 4,000 rpm and then quickly release the accelerator pedal so that the throttle valve is fully closed.

Standard voltage

VOLTAGE SPECIFICATION

Conditions	A/F Sensor Voltage Variations	Reference
(1)and(2)	Remains at approximately 3.3 V	Between 3.1 V and 3.5 V
(3)	Increases to 3.8 V or more	This occurs during engine deceleration (when fuel-cut performed)

HINT:

For more information, see Fig 1.

Fig 1: A/F Sensor Voltage Graph
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
If the output voltage of the A/F sensor remains at approximately 3.3 V (see Malfunction Condition diagram in Fig 1) under any conditions, including those above, the A/F sensor may have an open circuit. (This will also happen if the A/F sensor heater has an open circuit.)
If the output voltage of the A/F sensor remains at either approximately 3.8 V or more, or 2.8 V or less (see Malfunction Condition diagram inFig 1) under any conditions, including those above, the A/F sensor may have a short circuit.
The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and result in a momentary increase in the A/F sensor output voltage.
The ECM must establish a closed throttle valve position learning value to perform fuel cut. If the battery terminal has been reconnected, the vehicle must be driven over 16 km/h (10 mph) to allow the ECM to learn the closed throttle valve position.
When the vehicle is driven:
The output voltage of the A/F sensor may be below 2.8 V during fuel enrichment. For the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to overtake another vehicle. The A/F sensor is functioning normally.
The A/F sensor is a current output element; therefore, the current is converted into a voltage inside the ECM.
Measuring the voltage at the connectors of the A/F sensor or ECM will show a constant voltage result.

NG: Go to step 9

OK: Go to Next Step

PERFORM CONFIRMATION DRIVING PATTERN

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Read DTCs using Techstream.

Select the following menu items: Powertrain / Engine and ECT / Trouble Code.

Result

RESULT REFERENCE

Display (DTC Output)	Proceed To
P2195 or P2196	A
No output	B

B: END

A: Go to Next Step

REPLACE AIR-FUEL RATIO SENSOR
PERFORM CONFIRMATION DRIVING PATTERN

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Read DTCs using Techstream.

Select the following menu items: Powertrain / Engine and ECT / Trouble Code.

Result

RESULT REFERENCE

Display (DTC Output)	Proceed To
No output	A
P2195 or P2196	B

B: REPLACE ECM

A: END

INSPECT AIR-FUEL RATIO SENSOR (HEATER RESISTANCE) (See INSPECTION PROCEDURE )
NG: REPLACE AIR-FUEL RATIO SENSOR

OK: Go to Next Step
INSPECT INTEGRATION RELAY (EFI MAIN RELAY)
NG: REPLACE INTEGRATION RELAY (EFI MAIN RELAY)

OK: Go to Next Step

CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)

Disconnect the B7 A/F sensor connector.

Fig 2: Identifying A/F Sensor And ECM Connector Terminals

Turn the ignition switch ON.

Measure the voltage between the +B terminal of the A/F sensor connector and body ground.

Standard voltage

VOLTAGE SPECIFICATION

Tester Connections	Specified Conditions
B7-2 (+B) - Body ground	9 to 14 V

Turn the ignition switch OFF.
Disconnect the B30 ECM connector.

Measure the resistance.

Standard resistance (Check for open)

RESISTANCE SPECIFICATION

Tester Connections	Specified Conditions
B7-1 (HA1A) - B30-109 (HA1A)	Below 1 Ω
B7-3 (A1A+) - B30-112 (A1A+)	Below 1 Ω
B7-4 (A1A-) - B30-113 (A1A-)	Below 1 Ω

Standard resistance (Check for short)

RESISTANCE SPECIFICATION

Tester Connections	Specified Conditions
B7-1 (HA1A) or B30-109 (HA1A) - Body ground	10 kΩ or higher
B7-3 (A1A+) or B30-112 (A1A+) - Body ground	10 kΩ or higher
B7-4 (A1A-) or B30-113 (A1A-) - Body ground	10 kΩ or higher

Reconnect the ECM connector.
Reconnect the A/F sensor connector.

Fig 3: A/F Sensor Circuit Diagram (Bank 1 Sensor 1)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to Next Step

REPLACE AIR-FUEL RATIO SENSOR
PERFORM CONFIRMATION DRIVING PATTERN

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Read DTCs using Techstream.

Select the following menu items: Powertrain / Engine and ECT / Trouble Code.

Result

RESULT REFERENCE

Display (DTC Output)	Proceed To
No output	A
P2195 or P2196	B

B: REPLACE ECM

A: END