Inspection Procedure
HINT:
Intelligent tester only:
Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE TEST. The A/F CONTROL 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 A/F CONTROL operation using the intelligent tester.
- Connect the intelligent tester to the DLC3 with CAN VIM.
- 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 intelligent tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
- Perform the A/F CONTROL 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 A/F and HO2 sensors (AFS B1S1 (AFS B2S1) and O2S B1S2 (O2S B2S2)) displayed on the tester.
HINT:
- The A/F CONTROL 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:
STANDARD VOLTAGE TABLE
| Tester Display (Sensor) | Injection Volume | Status | Voltage |
|---|---|---|---|
| AFS B1S1 (AFS B2S1) (A/F) | +25% | Rich | Less than 3.0 |
| AFS B1S1 (AFS B2S1) (A/F) | -12.5% | Lean | More than 3.35 |
| O2S B1S2 (O2S B2S2) (HO2) | +25% | Rich | More than 0.55 |
| O2S B1S2 (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.
- Following the A/F CONTROL procedure enables technicians to check and graph the voltage outputs of both the A/F and HO2 sensors.
- To display the graph, enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2. Then press the YES button and ENTER button, followed by the F4 button.
HINT:
- DTC P2A00 may be also 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 the intelligent tester. 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.
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03)
- Connect the intelligent tester to the DLC3 with CAN VIM.
- Turn the ignition switch ON and turn the tester ON.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read the DTCs.
Result
RESULT REFERENCEDisplay (DTC Output) Proceed to P2A00 and/or P2A03 A P2A00 and/or P2A03 and other DTCs B HINT:
If any DTCs other than P2A00 and/or P2A03 are output, troubleshoot those DTCs first.
B: GO TO DTC TABLE
A: Go to next step
- INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
- Disconnect the A41 or A42 Air Fuel Ratio (A/F) sensor connector.
- Measure the resistance of the A/F sensor connector.
Standard resistance
RESISTANCE SPECIFICATIONTester Connection Specified Condition HT (1) - +B (2) 1.8 to 3.4 Ω at 20°C (68°F) HT (1) - A- (4) 10 kΩ or higher - Reconnect the A/F sensor connector.
NG: REPLACE AIR FUEL RATIO SENSOR
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: Go to next step
- CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
- Disconnect the A41 or A42 A/F sensor connector.
- Turn the ignition switch ON.
- Measure the voltage between the +B terminal of the A/F sensor connector and body ground.
Standard voltage
VOLTAGE SPECIFICATIONTester Connection Specified Condition +B (2) - Body ground 10 V or more - Turn the ignition switch OFF.
- Disconnect the E6 ECM connector.
- Measure the resistance.
Standard resistance (Check for open)
RESISTANCE SPECIFICATIONTester Connection Specified Condition HT (A41-1) - HA1A (E6-2) Below 1 Ω HT (A42-1) - HA2A (E6-1) A+ (A41-3) - A1A+ (E6-22) A+ (A42-3) - A2A+ (E6-23) A- (A41-*) - A1A- (E6-30) A- (A42-4) - A2A- (E6-31) Standard resistance (Check for short)
RESISTANCE SPECIFICATIONTester Connection Specified Condition HT (A41-1) or HA1A (E6-2) - Body ground 10 kΩ or higher HT (A42-1) or HA2A (E6-1) - Body ground A+ (A41-3) or A1A+ (E6-22) - Body ground A+ (A42-3) or A2A+ (E6-23) - Body ground A- (A41-4) or A1A- (E6-30) - Body ground A- (A42-4) or A2A- (E6-31) - Body ground - Reconnect the A/F sensor connector.
- Reconnect the ECM connector.
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
- PERFORM CONFIRMATION DRIVING PATTERN
- CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)
- Read the DTCs using the intelligent tester.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / PENDING CODES.
Result
RESULT REFERENCEDisplay (DTC Output) Proceed to P2A00 and/or P2A03 A No output B B: CHECK FOR INTERMITTENT PROBLEMS
A: Go to next step
- REPLACE AIR FUEL RATIO SENSOR
- PERFORM CONFIRMATION DRIVING PATTERN
- CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)
- Read the DTCs using the intelligent tester.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / PENDING CODES.
Result
RESULT REFERENCEDisplay (DTC Output) Proceed to P2A00 and/or P2A03 A No output B
A: CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (REFER TO DTC P0171 PROCEDURE)
B: END