DTC P2A00: A/F Sensor Circuit Slow Response (Bank 1 Sensor 1); DTC P2A03: A/F Sensor Circuit Slow Response (Bank 2 Sensor 1): Wiring Diagram
Refer to DTC P2195 .
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.
- 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 B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) 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 in the fuel injection volume.
FUEL INJECTION VOLUME SPECIFICATIONS
| Tester Display (Sensor) | Injection Volume | Status | Voltage |
|---|---|---|---|
| AFS B1 S1 or AFS B2 S1 (A/F) | +25 % | Rich | Less than 3.0 V |
| AFS B1 S1 or AFS B2 S1 (A/F) | -12.5 % | Lean | More than 3.35 V |
| O2S B1 S2 or O2S B2 S2 (HO2) | +25 % | Rich | More than 0.55 V |
| O2S B1 S2 or O2S B2 S2 (HO2) | -12.5 % | Lean | Less than 0.4 V |
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 AND HEATED OXYGEN SENSOR OUTPUT DELAY
| Case | A/F Sensor (Sensor 1) Output Voltage | HO2 Sensor (Sensor 2) Output Voltage | Main Suspected Trouble Area | ||
|---|---|---|---|---|---|
| 1 | Injection Volume +25 % -12.5 % | Injection Volume +25 % -12.5 % | - | ||
| Output Voltage More than 3.35 V Less than 3.0 V | Output Voltage More than 0.55 V Less than 0.4 V | ||||
| 2 | Injection Volume +25 % -12.5 % | Injection Volume +25 % -12.5 % |
|
||
| Output Voltage Almost no reaction | Output Voltage More than 0.55 V Less than 0.4 V | ||||
| 3 | Injection Volume +25 % -12.5 % | Injection Volume +25 % -12.5 % |
|
||
| Output Voltage More than 3.35 V Less than 3.0 V | Output Voltage Almost no reaction | ||||
| 4 | Injection volume +25 % -12.5 % | Injection Volume +25 % -12.5 % |
|
||
| Output Voltage Almost no reaction | Output Voltage Almost no reaction | ||||
- 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 B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2, and press the YES button and then the ENTER button followed by the F4 button.
HINT:
- DTC P2A00 or P2A03 may also 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 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 (See FREEZE FRAME DATA ).
- CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03)
- Connect the intelligent tester to the DLC3.
- Turn the engine switch on (IG).
- Turn the tester on.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read DTCs.
Result
RESULTDisplay (DTC Output) Proceed to P2A00 and/or P2A03 A P2A00 and/or P2A03 and other DTCs B HINT:
If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.
B : GO TO DTC CHART
A : Go To Next Step
- INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
- Disconnect the E42 or E38 A/F sensor connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance (Bank 1 sensor 1)
Standard resistance (Bank 2 sensor 1)
- Reconnect the A/F sensor connector.
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
STANDARD RESISTANCE (BANK 1 SENSOR 1)Tester Connection Condition Specified Condition HA1A (1) - +B (2) 20°C (68°F) 1.8 Ω to 3.4 Ω HA1A (1) - A1A- (4) - 10 kΩ or higher STANDARD RESISTANCE (BANK 2 SENSOR 1)Tester Connection Condition Specified Condition HA2A (1) - +B (2) 20°C (68°F) 1.8 Ω to 3.4 Ω HA2A (1) - A2A- (4) - 10 kΩ or higher NG : REPLACE AIR FUEL RATIO SENSOR
OK : Go To Next Step
- CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
- Disconnect the E42 or E38 A/F sensor connector.
- Turn the engine switch on (IG).
- Measure the voltage according to the value(s) in the table below.
Standard voltage
STANDARD VOLTAGETester Connection Specified Condition +B (E42-2) - Body ground 9 to 14 V +B (E38-2) - Body ground 9 to 14 V - Turn the engine switch off.
- Disconnect the E6 ECM connector.
- Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for open)
STANDARD RESISTANCE (CHECK FOR OPEN)Tester Connection Specified Condition HA1A(E42-1) - HA1A (E6-6) Below 1 Ω A1A+ (E42-3) - A1A+ (E6-18) Below 1 Ω A1A- (E42-4) - A1A- (E6-17) Below 1 Ω HA2A (E38-1) - HA2A (E6-4) Below 1 Ω A2A+ (E38-3) - A2A+ (E6-28) Below 1 Ω A2A- (E38-4) - A2A- (E6-27) Below 1 Ω Standard resistance (Check for short)
STANDARD RESISTANCE (CHECK FOR SHORT)Tester Connection Specified Condition HA1A(E42-1) or HA1A (E6-6) - Body ground 10 kΩ or higher A1A+ (E42-3) or A1A+ (E6-18) - Body ground 10 kΩ or higher A1A- (E42-4) or A1A- (E6-17) - Body ground 10 kΩ or higher HA2A (E38-1) or HA2A (E6-4) - Body ground 10 kΩ or higher A2A+ (E38-3) or A2A+ (E6-28) - Body ground 10 kΩ or higher A2A- (E38-4) or A2A- (E6-27) - Body ground 10 kΩ or higher - Reconnect the ECM connector.
- Reconnect the A/F sensor connector.
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 DTCs using the intelligent tester.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
Result
RESULTDisplay (DTC Output) Proceed to P2A00 and/or P2A03 A No output B B : REPLACE ECM
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 DTCs using the intelligent tester.
- Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
Result
RESULTDisplay (DTC Output) Proceed to No output A P2A00 and/or P2A03 B B : REPLACE ECM
A : Go to next step.
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