Inspection Procedure

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.
Select the following menu items on the tester: Powertrain/Engine/Active Test/Control the Injection Volume for A/F Sensor.
Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).

Monitor the voltage outputs of the A/F and HO2 sensors (AFS voltage B1S1 and O2S B1S2 or AFS voltage B2S1 and O2S B2S2) 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%.

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

Standard voltage

VOLTAGE SPECIFIED CONDITION

Tester Display (Sensor)	Injection Volumes	Status	Voltages
AFS voltage B1S1 or AFS voltage B2S1 (A/F)	+25%	Rich	Less than 3.1
AFS voltage B1S1 or AFS voltage B2S1 (A/F)	-12.5%	Lean	More than 3.5
O2S B1S2 or O2S B2S2 (HO2)	+25%	Rich	More than 0.55
O2S B1S2 or O2S B2S2 (HO2)	-12.5%	Lean	Less than 0.4

NOTE: The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.

AIR FUEL RATIO SENSOR (SENSOR 1) AND HEATED OXYGEN SENSOR (SENSOR 2) OUTPUT VOLTAGE

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	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/Active Test/Control the Injection Volume for A/F Sensor/A/F Control System/AFS voltage B1S1 and O2S B1S2 or AFS voltage B2S1 and O2S B2S2; then press the graph button on the Data List view.
HINT:
- Read freeze frame data using 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 traveling 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 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 DTC P0171, P0172, P0174 OR P0175)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON (do not run the engine).
Turn the Techstream on.
Select the following menu items: Powertrain/Engine/Data List/MAF.

Wait 30 seconds, and read the values on the Techstream.

Result

RESULT CHART

Tester Display	Condition	Standard Connection
MAF	Engine not running 30 seconds after ignition switch is turned ON	Below 0.33 g/sec.

B: GO TO DTC CHART

A: Go to Next Step

CHECK PCV HOSE CONNECTIONS
OK: PCV hose is connected correctly and is not damaged.

NG: REPAIR OR REPLACE PCV HOSE

OK: Go to Next Step
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leakage.
  OK: No leakage from the air induction system.
  
  NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM
  
  OK: Go to Next Step

PERFORM ACTIVE TEST USING TECHSTREAM (A/F CONTROL)

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.
Select the following menu items on the tester: Powertrain/Engine/Active Test/Control the Injection Volume for A/F Sensor.
Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).

Monitor the voltage outputs of the A/F and HO2 sensors (AFS voltage B1S1 and O2S B1S2 or AFS voltage B2S1 and O2S B2S2) 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%.

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

Standard voltage

VOLTAGE SPECIFIED CONDITION

Tester Display (Sensor)	Injection Volumes	Status	Voltages
AFS voltage B1S1 or AFS voltage B2S1 (A/F)	+25%	Rich	Less than 3.1
AFS voltage B1S1 or AFS voltage B2S1 (A/F)	-12.5%	Lean	More than 3.5
O2S B1S2 or O2S B2S2 (HO2)	+25%	Rich	More than 0.55
O2S B1S2 or O2S B2S2 (HO2)	-12.5%	Lean	Less than 0.4

Result

RESULT CHART

Status AFS voltage B1S1 or AFS voltage B2S1	Status O2S B1S2 or O2S B2S2	A/F Condition and A/F Sensor Condition	Misfires	Suspected Trouble Areas	Proceed to
Lean/Rich	Lean/Rich	Normal	-	-	C
Lean	Lean	Actual air-fuel ratio lean	May occur	PCV valve and hose PCV hose connections Injector blockage Gas leakage from exhaust system Air induction system Fuel pressure Mass Air Flow (MAF) meter Engine Coolant Temperature (ECT) sensor	A
Rich	Rich	Actual air-fuel ratio rich	-	Injector leakage or blockage Gas leakage from exhaust system Ignition system Fuel pressure MAF meter ECT sensor	A
Lean	Lean/Rich	A/F sensor malfunction	-	A/F sensor	B
Rich	Lean/Rich	A/F sensor malfunction	-	A/F sensor	B
Lean: During the Control the Injection Volume for A/F Sensor, the A/F sensor output voltage (AFS) is consistently more than 3.5 V, and the HO2 sensor output voltage (O2S) is consistently less than 0.4 V. Rich: During Control the Injection Volume for A/F Sensor, the AFS is consistently less than 3.1 V, and the O2S is consistently more than 0.55 V. Lean/Rich: During Control the Injection Volume for A/F Sensor of the Active Test, the output voltage of the heated oxygen sensor alternates correctly.

B: Go to step 11

C: Go to step 15

A: Go to Next Step

READ VALUE USING TECHSTREAM (COOLANT TEMP)
1. Connect Techstream to the DLC3.
2. Turn the ignition switch to ON and turn the tester on.
3. Select the following menu items: Powertrain/Engine/Data List/All Data/Coolant Temp.
4. Read the Coolant Temp twice, when the engine is both cold and warmed up.
  Standard:
  
  With cold engine: Same as ambient air temperature.
  
  With warm engine: Between 75°C and 95°C (167°F and 203°F)
  
  NG: REPLACE ENGINE COOLANT TEMPERATURE SENSOR
  
  OK: Go to Next Step

READ VALUE USING TECHSTREAM (MAF)

Connect the Techstream to the DLC3.
Turn the ignition switch to ON (do not run the engine).
Turn the Techstream on.
Select the following menu items: Powertrain/Engine/Data List/MAF.

Wait 30 seconds, and read the values on the Techstream.

Result

RESULT CHART

Tester Display	Condition	Proceed to
MAF	Engine not running 30 seconds after ignition switch is turned ON	Below 0.33 g/sec.

NG: REPLACE MASS AIR FLOW METER

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 FOR EXHAUST GAS LEAKS
OK: No gas leakage.

NG: REPAIR OR REPLACE EXHAUST SYSTEM

OK: Go to Next Step
CHECK FOR SPARKS AND IGNITION
1. Check for sparks and ignition (See ON-VEHICLE INSPECTION ).
  HINT:
  
  If the spark plugs or ignition system malfunction, engine misfire may occur. The misfire count can be read using Techstream. Select the following menu items: Powertrain/Engine/Data List/All Data/Cylinder #1 Misfire Count (to Cylinder #6 Misfire Count).
  
  NG: REPAIR OR REPLACE IGNITION SYSTEM
  
  OK: Go to Next Step
INSPECT FUEL INJECTOR ASSEMBLY (INJECTION AND VOLUME)
1. Inspect the fuel injector assembly (See INSPECTION ).
  HINT:
  
  If the injectors malfunction, engine misfire may occur. The misfire count can be read using Techstream. Select the following menu items: Powertrain/Engine/Data List/All Data/Cylinder #1 Misfire Count (to Cylinder #6 Misfire Count).
  
  NG: REPLACE FUEL INJECTOR ASSEMBLY (See REMOVAL )
  
  OK: Go to Next Step

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

Disconnect the A/F sensor connector.

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

Standard resistance (Bank 1 sensor 1)

RESISTANCE SPECIFIED CONDITIONS

Tester Connections	Specified Conditions
HA1A (1) - +B (2)	1.8 to 3.4 Ω at 20°C (68°F)
HA1A (1) - A1A- (4)	10 kΩ or higher

Standard resistance (Bank 2 sensor 1)

RESISTANCE SPECIFIED CONDITIONS

Tester Connections	Specified Conditions
HA2A (1) - +B (2)	1.8 to 3.4 Ω at 20°C (68°F)
HT2A (1) - A2A- (4)	10 kΩ or higher

Reconnect the A/F sensor connector.
NG: REPLACE AIR FUEL RATIO SENSOR (See REMOVAL )

Fig 1: Identifying B32 And B26 A/F Sensor Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step

INSPECT ENGINE ROOM JUNCTION BLOCK (A/F RELAY)

Remove the engine room junction block from the engine room R/B.

Measure the A/F relay resistance.

Standard resistance

RESISTANCE SPECIFIED CONDITIONS

Tester Connections	Specified Conditions
1F-1 - 1C-6	10 kΩ or higher
1F-1 - 1C-6	Below 1 Ω (when battery voltage applied to terminals 1D-5 and 1H-2)

Reinstall the engine room junction block.
NG: REPLACE ENGINE ROOM JUNCTION BLOCK

Fig 2: Identifying A/F Relay Connector On Engine Room Junction Block Assembly
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go to Next Step

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

Disconnect the A/F sensor connector.
Turn the ignition switch to ON.

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

Standard voltage

VOLTAGE SPECIFIED CONDITION

Tester Connections	Specified Conditions
+B (B32-2) - Body ground	9 to 14 V
+B (B26-2) - Body ground	9 to 14 V

Turn the ignition switch off.
Disconnect the ECM connector.

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

Standard resistance (Check for open)

RESISTANCE SPECIFIED CONDITIONS

Tester Connections	Specified Conditions
HA1A (B32-1) - HA1A (B50-86)	Below 1 Ω
A1A+ (B32-3) - A1A+ (B50-93)	Below 1 Ω
A1 A- (B32-4) - A1A- (B50-116)	Below 1 Ω
HA2A (B26-1) - HA2A (B50-109)	Below 1 Ω
A2A+ (B26-3) - A2A+ (B50-120)	Below 1 Ω
A2A- (B26-4) - A2A- (B50-119)	Below 1 Ω

Fig 3: Identifying A/F Sensor And B50 ECM Connector Terminals

Standard resistance (Check for short)

RESISTANCE SPECIFIED CONDITIONS

Tester Connections	Specified Conditions
HA1A (B32-1) or HA1A (B50-86) - Body ground	10 kΩ or higher
A1A+ (B32-3) or A1A+ (B50-93) - Body ground	10 kΩ or higher
A1A- (B32-4) or A1A- (B50-116) - Body ground	10 kΩ or higher
HA2A (B26-1) or HA2A (B50-109) - Body ground	10 kΩ or higher
A2A+ (B26-3) or A2A+ (B50-120) - Body ground	10 kΩ or higher
A2A- (B26-4) or A2A- (B50-119) - Body ground	10 kΩ or higher

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

Fig 4: A/F Sensor System 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
1. Replace the air fuel ratio sensor (See REMOVAL ).
PERFORM CONFIRMATION DRIVING PATTERN
1. Connect Techstream to the DLC3 (Procedure A).
2. Turn the ignition switch to ON and turn the tester on (Procedure B).
3. Clear the DTCs (See DTC CHECK/CLEAR ) (Procedure C).
4. Select the check mode using the tester (See CHECK MODE PROCEDURE ) (Procedure D).
5. Start the engine and warm it up with all the accessories switched off (Procedure E).
6. Drive the vehicle at between 38 mph and 75 mph (61 km/h and 120 km/h) and at an engine speed of between 1,400 rpm and 3,200 rpm for 3 to 5 minutes (Procedure F).
  
  Fig 5: Vehicle Driving Pattern
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  HINT:
  
  If the system is still malfunctioning, the MIL will be illuminated during procedure "F".
  
  NOTE: If the conditions in this test are not strictly followed, no malfunction will be detected.

CHECK WHETHER DTC OUTPUT RECURS (DTC P0171, P0172, P0174 OR P0175)

Select the following menu items: Powertrain/Engine/Trouble Codes/Pending.

Read the DTCs.

Result

DTC OUTPUT RESULT

Display (DTC Output)	Proceed to
No output	A
P0171, P0172, P0174 or P0175	B

B: Go to step 5

A: END