Toyota Sienna Service Manual: A/F Sensor Circuit Slow Response
DTC P2A00 A/F Sensor Circuit Slow Response (Bank 1
Sensor 1)
DTC P2A03 A/F Sensor Circuit Slow Response (Bank 2
Sensor 1)
HINT:
- DTC P2A00 indicates malfunctions related to the bank 1 A/F sensor.
- DTC P2A03 indicates malfunctions related to the bank 2 A/F sensor.
- Bank 1 refers to the bank that includes cylinder No. 1.
- Bank 2 refers to the bank that includes cylinder No. 2.
- Sensor 1 refers to the sensor mounted in front of the Three-Way
Catalytic Converter (TWC) and
located near the engine assembly.
DESCRIPTION
Refer to DTC P2195
MONITOR DESCRIPTION
After the engine is warmed up, the ECM performs air-fuel ratio feedback
control to maintain the air-fuel
ratio at the stoichiometric level. In addition, active A/F ratio control is
performed for approximately 10
seconds after preconditions are met in order to measure the A/F sensor response
rate. During active A/F
ratio control, the ECM forcibly increases and decreases the injection volume to
a certain amount, based
on the stoichiometric air-fuel ratio learned during normal air-fuel ratio
control, and measures the A/F
sensor response rate. The ECM receives a signal from the A/F sensor while
performing active A/F ratio
control and uses it to calculate the A/F sensor response rate deterioration
level.
If the value for A/F sensor response rate deterioration level is less than the
threshold, the ECM interprets
this as a malfunction and sets the DTC.
CONFIRMATION DRIVING PATTERN
HINT:
Performing this confirmation driving pattern will activate the A/F sensor
response monitor.
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to the ON position.
- Turn the tester on.
- Clear the DTCs (where set).
- Select the following menu items: DIAGNOSIS / ENHANCED OBD II / MONITOR
INFO / MONITOR
RESULT.
- Check that RES RATE B1S1 and RES RATE B2S1 is INCOMPL.
- Start the engine and warm it up (Procedure "A").
- Drive the vehicle at between 25 mph and 75 mph (40 km/h and 120 km/h)
for 3 minutes. However, the
vehicle should be driven at a constant speed (Procedure "B").
- Check the monitor result values on the intelligent tester by selecting
the following menu items:
DIAGNOSIS / ENHANCED OBD II / MONITOR INFO / MONITOR RESULT /RES RATE B1S1
and
RES RATE B2S1 / Enter.
- If the values indicated on the tester do not change, perform
READINESS MONITOR DRIVE
PATTERN for the A/F sensor and the heated oxygen sensor.
HINT:
Completion of all A/F sensor monitors is required to change the value in
test result.
- Note the value of the Monitor Result.
- Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / PENDING CODES.
- Check if any DTCs (any pending DTCs) are set.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
TYPICAL MALFUNCTION THRESHOLDS
MONITOR RESULT
Refer to CHECKING MONITOR STATUS.
WIRING DIAGRAM
Refer to DTC P2195.
INSPECTION PROCEDURE
HINT:
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 an 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 2500 rpm for
approximately 90 seconds.
- Select the following menu items on the tester: 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 voltage outputs of the A/F and HO2 sensors (AFS B1S1
and O2S B1S2 or AFS B2S1 and
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
NOTICE:
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, select the following menu items on the tester:
DIAGNOSIS / ENHANCED OBD II
/ ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and
O2S
B2S2. Press the YES button and then the ENTER button. Then press the F4 button.
HINT:
- DTC P2A00 or P2A03 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.
1 CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03)
- Connect the intelligent tester to the DLC3.
- Turn the ignition switch to the ON position.
- Turn the tester on.
- Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DTC INFO / CURRENT CODES.
- Read the DTCs.
Result
HINT:
If any DTCs other than P2A00 or P2A03 are output,
troubleshoot those DTCs first.
2 INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
- Disconnect the A5 or A6 A/F sensor connector.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance:
Bank 1
Bank 2
- Reconnect the A/F sensor connector.
Result
3 CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
- Disconnect the A5 or A6 A/F sensor connector.
- Turn the ignition switch to the ON position.
- Measure the voltage according to the value(s) in the
table below.
Standard voltage
- Turn the ignition switch off.
- Disconnect the E10 ECM connector.
- Measure the resistance according to the value(s) in the
table below.
Standard resistance:
Check for open
Check for short
- Reconnect the ECM connector.
- Reconnect the A/F sensor connector.
4 PERFORM CONFIRMATION DRIVING PATTERN
5 CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)
- Read the DTCs using the intelligent tester.
- Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DTC INFO / PENDING CODES.
Result
6 REPLACE AIR FUEL RATIO SENSOR
- Replace the air fuel ratio sensor (for 2WD model or 4WD model
7 PERFORM CONFIRMATION DRIVING PATTERN
8 CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)
- Read the DTCs using the intelligent tester.
- Select the following menu items: DIAGNOSIS /
ENHANCED OBD II / DTC INFO / PENDING CODES.
Result
END
DTC P2610 ECM / PCM Internal Engine Off Timer Performance
DTC SUMMARY
DESCRIPTION
To ensure the accuracy of the EVAP (Evaporative Emission) monitor values, the
soak timer, which is built
int ...
DESCRIPTION
LOCATION
The Active Control Engine Mount (ACM) system decreases engine vibration at
engine idling using the
ACM VSV. The VSV is controlled by a pulse signal transmitted to the VSV ...
Other materials:
TC and CG Terminal Circuit
DESCRIPTION
Connecting terminals TC and CG of the DLC3 causes the system to enter the
self-diagnostic mode. If a
malfunction is present, DTCs will be output.
HINT:
When a particular warning light remains blinking, a ground short in the wiring
of terminal TC of the DLC3
or an internal ground ...
Inspection
1. INSPECT SPIDER BEARING
(a) Check that the spider bearing moves smoothly by
turning the flange.
(b) Check for the looseness around the joint by strongly
moving the flange in the axial and radial directions.
HINT:
If necessary, replace the shaft.
2. INSPECT INTERMEDIATE SHAFT
(a) Usin ...
Removal
1. REMOVE REAR WINDOW SIDE GARNISH
ASSEMBLY
2. REMOVE REAR DOOR WINDOW FRAME SUBASSEMBLY
3. REMOVE SIDE TRIM BOARD COVER REAR
4. REMOVE REAR DOOR TRIM BOARD SUBASSEMBLY
5. REMOVE REAR DOOR GLASS RUN
6. REMOVE SLIDE DOOR WINDOW ASSEMBLY
7. REMOVE REAR DOOR GLASS WEATHERSTRIP
Put pro ...