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 (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.

1. Connect Techstream to the DLC3.
2. Put the engine in inspection mode (See INSPECTION MODE PROCEDURE ).
3. Turn the tester on.
4. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
5. On the tester, select the following menu items: Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor.
6. 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).
7. Monitor the voltage outputs 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 

Case	A/F Sensor (Sensor 1) Output Voltage		HO2 Sensor (Sensor 2) Output Voltage		Main Suspected Trouble Area
1	Injection Volume +025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume 025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	-
	Output Voltage More than 3.35 V Less than 3.0 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage More than 0.5 V Less than 0.4 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2	Injection Volume +025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume 025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	A/F sensor A/F sensor heater A/F sensor circuit
	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage More than 0.5 V Less than 0.4 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3	Injection Volume +025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume 025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	HO2 sensor HO2 sensor heater HO2 sensor circuit
	Output Voltage More than 3.35 V Less than 3.0 V	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4	Injection Volume +025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injection Volume 025% -12.5%	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Injector Fuel pressure Gas leakage from exhaust system (Air-fuel ratio extremely lean or rich)
	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002	Output Voltage Almost no reaction	Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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 / 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:

• DTC P2A00 may be set when the air-fuel ratio is stuck rich or lean.
• 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.
• Read freeze frame data using Techstream. The ECM (included in the hybrid vehicle control ECU) records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00) 
   1. Connect Techstream to the DLC3.
   2. Turn the power switch on (IG).
   3. Turn the tester on.
   4. Select the following menu items: Powertrain / Engine / Trouble Code.
   5. Read the DTCs.

   Result 

   RESULT CHART
   
   

   Display (DTC Output)	Proceed to
   P2A00	A
   P2A00 and other DTCs	B

   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 

2. INSPECT AIR-FUEL RATIO SENSOR (HEATER RESISTANCE)  (See INSPECTION PROCEDURE )

   NG: REPLACE AIR-FUEL RATIO SENSOR 

   OK: Go to next step 

3. CHECK HARNESS AND CONNECTOR (HYBRID VEHICLE CONTROL ECU -AIR-FUEL RATIO SENSOR)  (See INSPECTION PROCEDURE )

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: Go to next step 

4. PERFORM CONFIRMATION DRIVING PATTERN 
5. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00) 
   1. Connect Techstream to the DLC3.
   2. Turn the power switch on (IG) and turn the tester on.
   3. Select the following menu items: Powertrain / Engine / Trouble Code / Pending.
   4. Read the pending DTCs.

   Result 

   RESULT CHART
   
   

   Display (DTC Output)	Proceed to
   P2A00	A
   No output	B

   B: CHECK FOR INTERMITTENT PROBLEMS 

   A: Go to next step 

6. REPLACE AIR-FUEL RATIO SENSOR 
7. PERFORM CONFIRMATION DRIVING PATTERN 
8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00) 
   1. Connect Techstream to the DLC3.
   2. Turn the power switch on (IG) and turn the tester on.
   3. Select the following menu items: Powertrain / Engine / Trouble Code / Pending.
   4. Read the pending DTCs.

   Result 

   RESULT CHART
   
   

   Display (DTC Output)	Proceed to
   No output	A
   P2A00	B

   B: REPLACE HYBRID VEHICLE CONTROL ECU 

   A: END