Inspection Procedure

WARNING: This page is about a different variant/trim than selected.

HINT:

Hand-held tester only: It is possible the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The A/F CONTROL operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble areas are malfunctioning or not.

Perform the ACTIVE TEST A/F CONTROL operation.
HINT:

The A/F CONTROL operation lowers the injection volume 12.5 % or increases the injection volume 25 %.
1. Connect the hand-held tester to the DLC3 on the vehicle.
2. Turn the ignition switch ON.
3. Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
4. Enter the following menus: DIAGNOSIS/ENHANCED OBD II/ACTIVE TEST/A/F CONTROL.
5. Perform the A/F CONTROL operation with the engine idle (press the right or left button).

Result:

A/F sensor reacts in accordance with increase and decrease of injection volume:

+25 % --> RICH output: Less than 3.0 V

-12.5 % --> LEAN output: More than 3.35 V

Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:

+25 % --> RICH output: More than 0.55 V

-12.5 % --> LEAN output: Less than 0.4 V

NOTE: The A/F sensor output has a few seconds of delay and the heated oxygen sensor output has about 20 seconds of delay at maximum.

Fig 1: Active Test Graphical Representation

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The following A/F CONTROL procedure enables a technician to check and graph the voltage outputs of both the A/F sensor and the heated oxygen sensor.

For displaying the graph, enter "ACTIVE TEST/A/F CONTROL/USER DATA", select "AFS B1S1 and O2S B1S2" by pressing "YES" and push "ENTER". Then press "F4".

HINT:

Read freeze frame data using the hand-held tester or the OBDII scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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 high A/F sensor voltage could be caused by a RICH air fuel mixture. Check the conditions that might cause the engine to run with a RICH air fuel mixture.
A low A/F sensor voltage could be caused by a LEAN air fuel mixture. Check the conditions that might cause the engine to run with a LEAN air fuel mixture.

CHECK AIR INDUCTION SYSTEM
1. Check for vacuum leaks in air induction system.
  OK: No vacuum leak.
1. NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM
2. OK: GO TO NEXT STEP.
CHECK CONNECTION OF PCV HOSE
OK: PCV hose is connected correctly and PCV hose is not damaged.
1. NG: REPAIR OR REPLACE PCV HOSE
2. OK: GO TO NEXT STEP.

INSPECT FUEL INJECTOR ASSY (INJECTION AND VOLUME) (See ON-VEHICLE INSPECTION )

Standard:

FUEL INJECTOR ASSEMBLY INJECTION VOLUME SPECIFICATIONS

Injection Volume	Difference Between Each Injector
76 to 91 cm³ (4.6 to 5.5 cu in.) /15 seconds	15 cm³ (0.9 cu in.) or less

NG: REPLACE FUEL INJECTOR ASSY (See appropriate Fuel Systems article)
OK: GO TO NEXT STEP.

INSPECT MASS AIR FLOW METER

Remove the MAF meter.
Check the output voltage.
1. Apply battery voltage across terminals +B and EVG.
2. Connect the positive (+) tester probe to terminal VG, and negative (-) tester probe to terminal EVG.
3. Blow air into the MAF meter, and check that the voltage fluctuates.

Measure the resistance of the IAT terminals.

Fig 2: Temperature - Resistance Graph & IAT Terminal Identification

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard:

TESTER CONNECTION AND CONDITION SPECIFICATIONS

Tester Connection	Condition	Specified Condition
4 (THA) - 5 (E2)	-20 °C (-4°F)	13.6 to 18.4 kΩ
4 (THA) - 5 (E2)	20°C (68°F)	2.21 to 2.69 kΩ
4 (THA) - 5 (E2)	60°C (140°F)	0.49 to 0.67 kΩ

NG: REPLACE MASS AIR FLOW METER
OK: GO TO NEXT STEP.

INSPECT ENGINE COOLANT TEMPERATURE SENSOR (RESISTANCE)

Remove the ECT sensor.

Measure the resistance of the ECT sensor terminals.

Standard:

TESTER CONNECTION AND CONDITION SPECIFICATIONS

Tester Connection	Condition	Specified Condition
1 - 2	20°C (68°F)	2.32 to 2.59 kΩ
1 - 2	80°C (176°F)	0.310 to 0.326 kΩ

NOTE: When checking the ECT sensor in water, be careful not to allow water to go into the terminals. After the check, dry the sensor.

HINT:

Alternate procedure: Connect an ohmmeter to the installed ECT sensor and read the resistance. Use an infrared thermometer to measure the engine temperature in the immediate vicinity of the sensor. Compare these values to the resistance/temperature graph. Change the engine temperature (warm up or allow to cool down) and repeat the test.

Fig 3: Measuring ECT Sensor Resistance

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE ENGINE COOLANT TEMPERATURE
OK: GO TO NEXT STEP.

CHECK FOR SPARK AND IGNITION (See ON-VEHICLE INSPECTION )
OK: Spark occurs.
1. NG: REPAIR OR REPLACE
2. OK: GO TO NEXT STEP.

CHECK FUEL PRESSURE (See ON-VEHICLE INSPECTION )

Check the fuel pressure (high or low pressure).

Standard:

FUEL PRESSURE CONDITION SPECIFICATIONS

Item	Specified Condition
Fuel pressure	304 to 343 kPa (3.1 to 3.5 kgf/cm² , 44 to 55 psi)

NG: REPLACE FUEL SYSTEM
OK: GO TO NEXT STEP.

CHECK FOR EXHAUST GAS LEAKS
OK: No gas leak.
1. NG: REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT (See REPLACEMENT )
2. OK: GO TO NEXT STEP.
READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR (BANK 1 SENSOR 1))
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Warm up the A/F sensor (bank 1 sensor 1) by running the engine at 2,500 rpm for approximately 90 seconds.
3. Read A/F sensor voltage output on the hand-held tester or the OBD II scan tool.
4. Hand-held tester only:
  Enter the following menus: ENHANCED OBD II/SNAPSHOT/MANUAL SNAPSHOT/USER DATA.
5. Select "AFS B1 S1/ENGINE SPD" and press YES.
6. Monitor the A/F sensor voltage carefully.
7. Check the A/F sensor voltage output under the following conditions:
  1. Allow the engine to idle for 30 seconds.
  2. Running the engine at approximately 2,500 rpm (where engine RPM is not suddenly changed).
  3. Raise the engine speed to 4,000 rpm and quickly release the accelerator pedal so that the throttle is fully closed.
    Standard:
    
    Condition (1) and (2)
    
    Voltage change of 3.3 V (0.66 V)* (between approximately 3.1 to 3.5 V), as shown in the illustration.
    
    Condition (3)
    
    A/F sensor voltage increases to 3.8 V (0.76 V)* or more when fuel is cut during engine deceleration, as shown in the illustration.
    
    *: Voltage when using the OBD II scan tool.
    
    Fig 4: Engine RPM And Air Fuel Sensor Voltage Graphical Representation At Normal And Malfunction Conditions
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
HINT:
- Whenever the output voltage of the A/F sensor remains at approximately 3.3 V (0.660 V) (Voltage when using the OBD II scan tool) under any condition as well as the above conditions, the A/F sensor may have an open circuit (this will happen also when the A/F sensor heater has an open circuit). See Fig 4.
- Whenever the output voltage of the A/F sensor remains at a certain value of approximately 3.8 V (0.76 V) (Voltage when using the OBD II scan tool) or more, or 2.8 V (0.56 V) (Voltage when using the OBD II scan tool) or less under any condition as well as the above conditions, the A/F sensor may have a short circuit. See Fig 4.
- The ECM will stop fuel injection (fuel cut) during engine deceleration. This will cause a LEAN condition and should result in a momentary increase in A/F sensor voltage output.
- The ECM must establish a closed throttle position learned value to perform fuel cut. If the battery terminal has been disconnected, the vehicle must be driven over 10 mph (16 km/h) to allow the ECM to learn the closed throttle position.
- When the vehicle is driven:
- You may notice that the output voltage of the A/F sensor is below 2.8 V (0.76 V) (Voltage when using the OBD II scan tool) during fuel enrichment. For example, when the vehicle tries to overtake another vehicle on a highway, the vehicle speed is suddenly increased with the accelerator pedal fully depressed. The A/F sensor is functioning normally-
- The A/F sensor is a current output element, and therefore the current is converted into voltage inside the ECM. If measuring voltage at connectors of A/F sensor or ECM, you will observe a constant voltage.
1. OK: Go to step 17
2. NG: GO TO NEXT STEP.

INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

Disconnect the A6 A/F sensor connector.

Measure the resistance of the A/F sensor terminals.

Fig 5: Identifying AF Sensor Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard:

TESTER CONNECTION AND CONDITION SPECIFICATIONS

Tester Connection	Condition	Specified Condition
1 (HT) - 2 (+B)	20°C (68°F)	0.8 to 1.4 kΩ
1 (HT) - 2 (+B)	800°C (1,472°F	1.8 to 3.2 kΩ

NG: REPLACE AIR FUEL RATIO SENSOR
OK: GO TO NEXT STEP.

INSPECT RELAY (EFI)

Remove the EFI relay from the engine room J/B.

Measure the resistance of the EFI relay.

Fig 6: Identifying EFI Relay Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Standard:

TESTER CONNECTION AND CONDITION SPECIFICATIONS

Tester Connection	Specified Condition
3 - 5	10 kΩ or higher
3 - 5	Below 1 Ω (when battery voltage is applied to terminals 1 and 2)

NG: REPLACE RELAY
OK: GO TO NEXT STEP.

CHECK WIRE HARNESS (A/F SENSOR - ECM)

Disconnect the A6 A/F sensor connector.
Disconnect the E8 ECM connector.

Measure the resistance of the wire harness side connectors.

Fig 7: Identifying AF Sensor And ECM Connector Terminals

Standard:

TESTER CONNECTION AND CONDITION SPECIFICATIONS

Tester Connection	Specified Condition
A6-3 (AF+) -A6-4 (AF-) -A6-1 (HT) - E8-23 (A1A+) E8-31 (A1A-) E8-5 (HA1A)	Below 1 Ω
A6-3 A6-4 A6-1 (AF+) or E8-23 (A1A+) - Body ground (AF-) or E8-31 (A1A-) - Body ground (HT) or E8-5 (HA1A) - Bodv around	10 kΩ or higher

Fig 8: Bank 1 Sensor 1 Sytem Drawing

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR
OK: GO TO NEXT STEP.

REPLACE AIR FUEL RATIO SENSOR
1. GO TO NEXT STEP.
PERFORM CONFIRMATION DRIVING PATTERN

Fig 9: Confirmation Driving Pattern
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Clear the DTCs.
  1. Disconnect the battery cable or remove the EFI NO. 1 and ETCS fuses for 60 seconds or more.
2. Connect the hand-held tester to the DLC3.
3. Switch the hand-held tester from the normal mode to the check mode (see CHECK MODE PROCEDURE ).
4. Start the engine and warm it up with all the accessory switches OFF.
5. Drive the vehicle at 38 to 75 mph (60 to 120 km/h) and engine speed at 1,400 to 3,200 rpm for 3 to 5 minutes.
HINT:

If a malfunction exists, the MIL will be illuminated during step ( e).

NOTE: If the conditions in this test are not strictly followed, detecting a malfunction may be difficult. If you do not have a hand-held tester, turn the ignition switch OFF after performing steps ( d) to ( e), and then do step ( e) again.
1. GO TO NEXT STEP.

READ OUTPUT DTC (DTC P0171, P0172 ARE OUTPUT AGAIN)

Read the DTC using the hand-held tester or the OBD II scan tool.

Result:

DTC RESULT

Display (DTC Output)	Proceed to
DTC P0171, P0172 are not output again	A
DTC P0171, P0172 are output again	B

B: REPLACE ECM (See REPLACEMENT ) AND PERFORM CONFIRMATION DRIVING PATTERN (Refer to step 14 )
A: GO TO NEXT STEP.

CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
1. NO: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
2. YES: DTC IS CAUSED BY RUNNING OUT OF FUEL (DTCS P0171, P0172)
PERFORM CONFIRMATION DRIVING PATTERN
HINT:

Clear all DTCs prior to performing the confirmation driving pattern (refer to step 14).
1. GO TO NEXT STEP.

READ OUTPUT DTC (DTC P0171, P0172 ARE OUTPUT AGAIN)

Read the DTC using the hand-held tester or the OBD II scan tool.

Result:

DTC RESULT

Display (DTC Output)	Proceed to
DTC P0171, P0172 are output again	A
DTC P0171, P0172 are not output again	B

B: Go to step 22
A: GO TO NEXT STEP.

REPLACE AIR FUEL RATIO SENSOR
1. GO TO NEXT STEP.
PERFORM CONFIRMATION DRIVING PATTERN
HINT:

Clear all DTCs prior to performing the confirmation driving pattern (refer to step 14).
1. GO TO NEXT STEP.

READ OUTPUT PTC (PTC P0171, P0172 ARE OUTPUT AGAIN)

Read the DTC using the hand-held tester or the OBD II scan tool.

Result:

DTC RESULT

Display (DTC Output)	Proceed to
DTC P0171, P0172 are not output again	A
DTC P0171, P0172 are output again	B

B: REPLACE ECM (See REPLACEMENT ) AND PERFORM) CONFIRMATION DRIVING PATTERN/(Refer to step 14 )
A: GO TO NEXT STEP.

CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
1. NO: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )
2. YES: DTC IS CAUSED SHORTAGE OF FUEL (DTCS P0171, P0172)