Inspection Procedure

HINT:

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 sensor, heated oxygen 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 the Techstream.

Connect the Techstream to the DLC3.
Start the engine.
Turn the Techstream on.
Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F sensor.
Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume.)
Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS B1 S1 and O2S B1 S2) displayed on the Techstream.

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%.
Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

VOLTAGE STATUS CHART

Techstream Display (Sensor)	Injection Volume	Status	Voltage
AFS B1 S1 (air fuel ratio)	+25%	Rich	Less than 3.0 V
AFS B1 S1 (air fuel ratio)	-12.5%	Lean	More than 3.35 V
O2S B1 S2 (heated oxygen)	+25%	Rich	More than 0.55 V
O2S B1 S2 (heated oxygen)	-12.5%	Lean	Less than 0.4 V

NOTE: The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen sensor has a maximum output delay of approximately 20 seconds.

MAIN SUSPECTED TROUBLE AREA

Case	Air Fuel Ratio Sensor (Sensor 1) Output Voltage	Heated Oxygen Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
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	Injector Fuel pressure Gas leak from exhaust system (Air fuel ratio extremely rich or lean)

Following the Control the Injection Volume for A/F sensor procedure enables technicians to check and graph the voltage outputs of both the air fuel ratio and heated oxygen sensors.
To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / AFS B1 S1 and O2S B1 S2; then press the graph button on the Data List view.

HINT:

Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
A low air fuel ratio sensor voltage could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to run rich.
A high air fuel ratio 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 the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result

RESULT CHART

Result	Proceed to
DTC P2195 or P2196 is output	A
DTC P2195 or P2196 and other DTCs are output	B

HINT:

If any DTCs other than P2195 and P2196 are output, troubleshoot those DTCs first.

B: GO TO DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A: Go to next step

CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
1. Has the vehicle run out of fuel in the past?
  NO: Go to step 3
  
  YES: DTC CAUSED BY RUNNING OUT OF FUEL

READ VALUE USING TECHSTREAM (TEST VALUE OF AIR FUEL RATIO SENSOR)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Clear DTCs (See DTC CHECK / CLEAR ).
Allow the vehicle to drive in accordance with the drive pattern described in the CONFIRMATION DRIVING PATTERN.
Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor /Status 2.
Check that the status 2 of O2 Sensor is Complete.
If the status is still Incomplete, perform the drive pattern increasing the vehicle speed and using the second gear to decelerate the vehicle.
Enter the following menus: Powertrain / Engine and ECT / Monitor / O2 Sensor / Details / RANGE B1 S1.

Check the test value of the air fuel ratio sensor output current during fuel-cut.

Result

RESULT CHART

Result	Proceed to
Within normal range (1.0 mA or higher, and below 3.6 mA)	A
Outside normal range (Below 1.0 mA, or 3.6 mA or higher)	B

B: Go to step 18

A: Go to next step

READ VALUE USING TECHSTREAM (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR)

Connect the Techstream to the DLC3.
Start the engine.
Turn the Techstream on.
Warm up the air fuel ratio sensor at an engine speed of 2500 rpm for 90 seconds.
Enter the following menus: Powertrain / Engine and ECT / Data List / AFS B1 S1 and Engine Speed, then press the Record button.

Check the air fuel ratio sensor voltage three 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 2500 rpm (without any sudden changes in engine speed)
Raise the engine speed to 4000 rpm and then quickly release the accelerator pedal so that the throttle valve is fully closed.

Standard Voltage

VOLTAGE REFERENCE

Condition	Air Fuel Ratio Sensor Voltage Variation	Reference
(1) and (2)	Changes at approximately 3.3 V	Between 3.1 V and 3.5 V
(3)	Increases to 3.8 V or higher	This occurs during engine deceleration (when fuel-cut performed)

HINT:

For more information, see the diagrams below.

Fig 1: Air Fuel Ratio Sensor Voltage And Engine RPM Chart

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

If the output voltage of the air fuel ratio sensor remains at approximately 3.3 V (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have an open circuit. (This will also happen if the air fuel ratio sensor heater has an open circuit.)
If the output voltage of the air fuel ratio sensor remains at either approximately 3.8 V or higher, or below 2.8 V (see Malfunction Condition diagram) under any conditions, including those above, the air fuel ratio sensor may have a short circuit.
The ECM stops fuel injection (fuel cut) during engine deceleration. This causes a lean condition and results in a momentary increase in the air fuel ratio 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 10 mph (16 km/h) to allow the ECM to learn the closed throttle valve position.
When the vehicle is driven:
The output voltage of the air fuel ratio 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 air fuel ratio sensor is functioning normally.
The air fuel ratio 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 air fuel ratio sensor or ECM will show a constant voltage result.
NG: Go to step 10

OK: Go to next step

PERFORM CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Clear DTCs.
5. Switch the ECM from normal mode to check mode.
6. Drive the vehicle referring the Confirmation Driving Pattern.

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result

RESULT CHART

Result	Proceed to
DTC P2195 or P2196 is output	A
DTC is not output	B

B: CHECK FOR INTERMITTENT PROBLEMS

A: Go to next step

REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor (See REMOVAL ).
PERFORM CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Clear DTCs.
5. Switch the ECM from normal mode to check mode.
6. Drive the vehicle referring the Confirmation Driving Pattern.

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result

RESULT CHART

Result	Proceed to
DTC is not output	A
DTC P2195 or P2196 is output	B

B: REPLACE ECM (See REMOVAL )

A: END

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) (See COMPONENT OPERATING RANGE )
NG: REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

OK: Go to next step

CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

Disconnect the air fuel ratio sensor connector.
Disconnect the ECM connector.

Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open)

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
B37-1 (HA1A) - B29-109 (HA1A)	Always	Below 1 Ω
B37-3 (A1A+) - B29-112 (A1A+)
B37-4 (A1A-) - B29-113 (A1A-)

Standard Resistance (Check for Short)

TESTER CONNECTION SPECIFIED CONDITION CHART

Tester Connection	Condition	Specified Condition
B37-1 (HA1A) or B29-109 (HA1A) - Body ground	Always	10 kΩ or higher
B37-3 (A1A+) or B29-112 (A1A+) - Body ground
B37-4 (A1A-) or B29-113 (A1A-) - Body ground

Reconnect the air fuel ratio sensor connector.
Reconnect the ECM connector.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

Fig 2: Identifying ECM Connector And Air Fuel Ratio Sensor Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to next step

CHECK INTAKE SYSTEM
1. Check the intake system for vacuum leak (See INTAKE SYSTEM ).
  OK: No leaks from intake system .
  
  NG: REPAIR OR REPLACE INTAKE SYSTEM
  
  OK: Go to next step
CHECK FUEL PRESSURE
1. Check the fuel pressure (See ON-VEHICLE INSPECTION ).
  NG: REPAIR OR REPLACE FUEL SYSTEM
  
  OK: Go to next step
INSPECT FUEL INJECTOR
1. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor) (See INSPECTION ).
  NG: REPLACE FUEL INJECTOR (See REMOVAL )
  
  OK: Go to next step
REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor (See REMOVAL ).
PERFORM CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Clear DTCs.
5. Switch the ECM from normal mode to check mode.
6. Drive the vehicle referring the Confirmation Driving Pattern.

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result

RESULT CHART

Result	Proceed to
DTC is not output	A
DTC P2195 or P2196 is output	B

B: REPLACE ECM (See REMOVAL )

A: END

REPLACE AIR FUEL RATIO SENSOR
1. Replace the air fuel ratio sensor (See REMOVAL ).
PERFORM CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Clear DTCs.
5. Switch the ECM from normal mode to check mode.
6. Drive the vehicle referring the Confirmation Driving Pattern.

CHECK WHETHER DTC OUTPUT RECURS (DTC P2195 OR P2196)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON.
Turn the Techstream on.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Result

RESULT CHART

Result	Proceed to
DTC is not output	A
DTC P2195 or P2196 (Air fuel ratio sensor pending DTCs) is output	B

B: REPLACE ECM (See REMOVAL )

A: END