- Open or short in A/F sensor circuit (for bank 1)
- A/F sensor (for bank 1)
- ECM
| Last Modified: 11-29-2007 | 1.6 C | |
| Service Category: Engine/Hybrid System | Section: Engine Control | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM0000013H801XX |
| Title: 2UZ-FE ENGINE CONTROL: SFI SYSTEM: CAUTION / NOTICE / HINT (2008 Sequoia) | ||
|
DTC |
P2A00 |
A/F Sensor Circuit Slow Response (Bank 1 Sensor 1) |
|
DTC |
P2A03 |
A/F Sensor Circuit Slow Response (Bank 2 Sensor 1) |
CAUTION / NOTICE / HINT
DESCRIPTION
Refer to DTC P2195
.
|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P2A00 |
Calculated value of air-fuel ratio (A/F) sensor response rate deterioration level less than threshold (2 trip detection logic) |
|
|
P2A03 |
Calculated value of air-fuel ratio (A/F) sensor response rate deterioration level less than threshold (2 trip detection logic) |
|
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 control is performed for approximately 10 seconds after the preconditions are met in order to measure the A/F sensor response rate. During active A/F control, the ECM forcibly increases and decreases the injection volume 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 control and uses it to calculate the A/F sensor response rate deterioration level.
If the A/F sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and stores the DTC.
CONFIRMATION DRIVING PATTERN
HINT:
Performing this confirmation pattern will activate the A/F sensor response monitor.
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Warm-up the engine until the engine coolant temperature is 75°C (167°F) or higher [A].
(d) Drive the vehicle at between 60 km/h and 120 km/h (40 mph and 75 mph) for at least 10 minutes [B].
(e) Drive the vehicle at 60 km/h (40 mph) or more and decelerate the vehicle for 5 seconds or more. Perform this 3 times [C].
(f) Turn the Techstream ON.
(g) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
(h) Input DTCs: P2A00 and P2A03.
(i) Check the DTC monitor is NORMAL. If the DTC monitor is INCOMPLETE, perform the drive pattern adding the vehicle speed and using the second gear to decelerate the vehicle.
MONITOR STRATEGY
|
Related DTCs |
P2A00: Air-Fuel Ratio (A/F) sensor slow response (bank 1) P2A03: Air-Fuel Ratio (A/F) sensor slow response (bank 2) |
|
Required Sensors/Components (Main) |
A/F sensor |
|
Required Sensors/Components (Related) |
Vehicle speed sensor, Crankshaft position sensor |
|
Frequency of Operation |
Once per driving cycle |
|
Duration |
10 to 15 seconds |
|
MIL Operation |
2 driving cycles |
|
Sequence of Operation |
None |
TYPICAL ENABLING CONDITIONS
|
Monitor runs whenever following DTCs not present |
P0031, P0032, P0051, P0052 (A/F Sensor Heater - Sensor 1) P0102 - P0103 (MAF meter) P0110 - P0113 (IAT sensor) P0115 - P0118 (ECT sensor) P0120 - P0223, P2135 (TP sensor) P0125 (Insufficient ECT for Closed Loop) P0171, P0172 (Fuel system) P0300 - P0308 (Misfire) P0335 (CKP sensor) P0455, P0456 (EVAP system) P0500 (VSS) P2196, P2198 (A/F sensor - rationality) P2237, P2240 (A/F sensor - open) P2440 (AIR control valve stuck open) P2441 (AIR control valve stuck close) P2444 (AIP stuck On) P2445 (AIP stuck Off) |
|
Active A/F control |
Performing |
|
Active A/F control performed when following conditions met |
- |
|
Engine coolant temperature |
75°C (167°F) or more |
|
Battery voltage |
11 V or more |
|
Idle |
OFF |
|
Engine RPM |
Less than 4000 rpm |
|
A/F sensor status |
Activated |
|
Fuel-cut |
OFF |
|
Engine load |
10 to 70% |
|
Shift position |
2 or more |
|
Catalyst monitor |
Not yet |
|
Intake air amount |
2.5 to 14 g/sec. |
TYPICAL MALFUNCTION THRESHOLDS
|
Response rate deterioration level |
Less than 0.12 V |
MONITOR RESULT
Refer to Checking Monitor Status
.
WIRING DIAGRAM
Refer to DTC P2195
.
INSPECTION PROCEDURE
HINT:
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 the Techstream.
(a) Connect the Techstream to the DLC3.
(b) Start the engine.
(c) Turn the Techstream ON.
(d) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
(e) Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/ F sensor.
(f) Perform the Active Test operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume.)
(g) 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 Techstream.
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:
Tester Display
(Sensor)
Injection Volume
Status
Voltage
AFS B1 S1
(A/F)
+25%
Rich
Less than 3.0
-12.5%
Lean
More than 3.35
O2S B1 S2
(HO2)
+25%
Rich
More than 0.55
-12.5%
Lean
Less than 0.4
AFS B2 S1
(A/F)
+25%
Rich
Less than 3.0
-12.5%
Lean
More than 3.35
O2S B2 S2
(HO2)
+25%
Rich
More than 0.55
-12.5%
Lean
Less than 0.4
NOTICE:
The A/F sensor has an output delay of a few seconds and the HO2 sensor has a maximum output delay of approximately 20 seconds.
|
Case |
A/F Sensor (Sensor 1) Output Voltage |
HO2 Sensor (Sensor 2) Output Voltage |
Main Suspected Trouble Area |
|---|---|---|---|
|
1 |
|
|
- |
|
2 |
|
|
|
|
3 |
|
|
|
|
4 |
|
|
|
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, enter the following menus using the Techstream: Powertrain / Engine / Active Test / Control the Injection Volume for A/ F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2, then press the graph button on the Data List view.
HINT:
- Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.
- DTC P2A00 indicates malfunctions related to the bank 1 A/F sensor.
- DTC P2A03 indicates malfunctions related to the bank 2 A/F sensor.
- For Bank 1 refers to the bank that includes No. 1 cylinder.
- For Bank 2 refers to the bank that includes No. 2 cylinder.
- DTC P2A00 or P2A03 may 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 Techstream. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.
PROCEDURE
|
1. |
CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream ON.
(d) Enter the following menus: Powertrain / Engine / Trouble Codes.
(e) Read DTCs.
Result
|
Result |
Proceed to |
|---|---|
|
P2A00 and/or P2A03 are output |
A |
|
P2A00 and/or P2A03 and other DTCs are output |
B |
HINT:
If any DTCs relating to the A/F sensor (DTCs for the A/F sensor heater or A/F sensor admittance) are output, troubleshoot those DTCs first.
|
|
2. |
INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
|
|
|
3. |
CHECK HARNESS AND CONNECTOR (ECM - AIR-FUEL RATIO SENSOR)
|
|
|
4. |
PERFORM CONFIRMATION DRIVING PATTERN |
|
|
5. |
CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream ON.
(d) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
(e) Read pending DTCs.
Result
|
Result |
Proceed to |
|---|---|
|
P2A00 and/or P2A03 is output |
A |
|
No DTC is output |
B |
|
|
6. |
REPLACE AIR FUEL RATIO SENSOR |
(a) Replace the air fuel ratio sensor
.
|
|
7. |
PERFORM CONFIRMATION DRIVING PATTERN |
|
|
8. |
CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03) |
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream ON.
(d) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.
(e) Read pending DTCs.
Result
|
Result |
Proceed to |
|---|---|
|
No DTC is output |
A |
|
P2A00 and/or P2A03 are output |
B |
|
|
|