| DTC Code | DTC Name |
|---|---|
| P003012 | HO2S Heater Control Bank 1 Sensor 1 Circuit Short to Battery |
| P003013 | HO2S Heater Control Bank 1 Sensor 1 Circuit Open |
| P005012 | HO2S Heater Control Bank 2 Sensor 1 Circuit Short to Battery |
| P005013 | HO2S Heater Control Bank 2 Sensor 1 Circuit Open |
| P101A9E | A/F Sensor Heater Performance Bank 1 Sensor 1 Stuck On |
| P103A9E | A/F Sensor Heater Performance Bank 2 Sensor 1 Stuck On |
DESCRIPTION
The air fuel ratio sensor (sensor 1) generates voltage* that corresponds to the actual air fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air fuel ratio. The ECM determines the deviation from the stoichiometric air fuel ratio level, and regulates the fuel injection time. If the air fuel ratio sensor (sensor 1) malfunctions, the ECM is unable to control the air fuel ratio accurately.
The air fuel ratio sensor (sensor 1) is a planar type and integrated with a heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), current flows to the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are a narrow type. The heat generated by the heater is conducted to the solid electrolyte through alumina, therefore sensor activation is accelerated.
In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a three-way catalytic converter is used. For the most efficient use of the three-way catalytic converter, the air fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.
*: Value changes inside the ECM. Since the air fuel ratio sensor is a current output element, the current is converted into a voltage inside the ECM. Any measurements taken at the air fuel ratio sensor or ECM connectors will show a constant voltage.
Tech Tips
When any of these DTCs are stored, the ECM enters fail-safe mode. The ECM turns off the air fuel ratio sensor (sensor 1) heater in fail-safe mode. Fail-safe mode continues until the power switch is turned off.
Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
The ECM has a pulse width modulated control circuit to adjust the current through the heater. The air fuel ratio sensor (sensor 1) heater circuit uses a relay on the +B side of the circuit.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| P003012 | HO2S Heater Control Bank 1 Sensor 1 Circuit Short to Battery | Air fuel ratio sensor (bank 1 sensor 1) heater current reaches the high limit (1 trip detection logic). |
|
Comes on | DTC stored | SAE: P0032 |
| P003013 | HO2S Heater Control Bank 1 Sensor 1 Circuit Open | Air fuel ratio sensor (bank 1 sensor 1) heater current is less than 0.8 A, even when the air fuel ratio sensor heater duty cycle is 30% or higher (1 trip detection logic). |
|
Comes on | DTC stored | SAE: P0031 |
| P005012 | HO2S Heater Control Bank 2 Sensor 1 Circuit Short to Battery | Air fuel ratio sensor (bank 2 sensor 1) heater current reaches the high limit (1 trip detection logic). |
|
Comes on | DTC stored | SAE: P0052 |
| P005013 | HO2S Heater Control Bank 2 Sensor 1 Circuit Open | Air fuel ratio sensor (bank 2 sensor 1) heater current is less than 0.8 A, even when the air fuel ratio sensor heater duty cycle is 30% or higher (1 trip detection logic). |
|
Comes on | DTC stored | SAE: P0051 |
| P101A9E | A/F Sensor Heater Performance Bank 1 Sensor 1 Stuck On | Air fuel ratio sensor (bank 1 sensor 1) heater current is higher than the specified value while the heater is not operating (1 trip detection logic). |
|
Comes on | DTC stored | SAE: P101D |
| P103A9E | A/F Sensor Heater Performance Bank 2 Sensor 1 Stuck On | Air fuel ratio sensor (bank 2 sensor 1) heater current is higher than the specified value while the heater is not operating (1 trip detection logic). |
|
Comes on | DTC stored | SAE: P103D |
MONITOR DESCRIPTION
The ECM uses information from the air fuel ratio sensor (sensor 1) to regulate the air fuel ratio and keep it close to the stoichiometric level. This maximizes the ability of the three-way catalytic converter to purify the exhaust gases.
The air fuel ratio sensor (sensor 1) detects oxygen levels in the exhaust gas and transmits the information to the ECM. The inner surface of the sensor element is exposed to the outside air. The outer surface of the sensor element is exposed to the exhaust gas. The sensor element is made of platinum-coated zirconia and includes an integrated heating element.
The zirconia element generates a small voltage when there is a large difference in the oxygen concentrations between the exhaust gas and outside air. The platinum coating amplifies this voltage generation.
The air fuel ratio sensor (sensor 1) is more efficient when heated. When the exhaust gas temperature is low, the sensor cannot generate useful voltage signals without supplementary heating. The ECM regulates the supplementary heating using a duty-cycle approach to adjust the average current in the sensor heater element. If the heater current is outside the normal range, the signal transmitted by the air fuel ratio sensor (sensor 1) becomes inaccurate. As a result, the ECM is unable to regulate the air fuel ratio properly.
When the current in the air fuel ratio sensor (sensor 1) heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and stores a DTC.
MONITOR STRATEGY
| Frequency of Operation | Continuous |
TYPICAL ENABLING CONDITIONS
| Output duty cycle | 30% or higher |
| Output duty cycle | Higher than 0% |
| Output duty cycle | Less than 60% |
CONFIRMATION DRIVING PATTERN
Connect the GTS to the DLC3.
Turn the power switch on (IG) and turn the GTS on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG) and turn the GTS on [A].
Put the engine in Inspection Mode (2WD for measuring Exhaust Gas).
Start the engine and idle it for 5 minutes or more [B].
With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 2500 rpm for 1 minute [C].
Tech Tips
During charge control, the engine speed is set at idle. Therefore, the engine speed does not increase when depressing the accelerator pedal. In this case, perform steps [C] and [D] after charge control has completed.
Idle the engine for 5 minutes or more [D].
Enter the following menus: Powertrain / Engine / Trouble Codes [E].
Read the pending DTCs.
Tech Tips
If a pending DTC is output, the system is malfunctioning.
If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine / Utility / All Readiness.
Input the DTC: P003012, P003013, P005012, P005013, P101A9E or P103A9E.
Check the DTC judgment result.
| GTS Display | Description |
|---|---|
| NORMAL |
|
| ABNORMAL |
|
| INCOMPLETE |
|
Tech Tips
If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE, perform steps [B] through [E] again.
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Note
Inspect the fuses for circuits related to this system before performing the following procedure.
Vehicle Control History may be stored in the hybrid vehicle control ECU if the engine is malfunctioning. Certain vehicle condition information is recorded when Vehicle Control History is stored. Reading the vehicle conditions recorded in both the freeze frame data and Vehicle Control History can be useful for troubleshooting.
(Select Powertrain in Health Check and then check the time stamp data.)
If any "Engine Malfunction" Vehicle Control History item has been stored in the hybrid vehicle control ECU, make sure to clear it. However, as all Vehicle Control History items are cleared simultaneously, if any Vehicle Control History items other than "Engine Malfunction" are stored, make sure to perform any troubleshooting for them before clearing Vehicle Control History.
Tech Tips
Refer to "Data List / Active Test" [A/F (O2) Sensor Heater Duty Ratio B1S1 and A/F (O2) Sensor Heater Duty Ratio B2S1].
Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.
Bank 2 refers to the bank that does not include the No. 1 cylinder.
Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
Change the fuel injection volume using the Control the Injection Volume for A/F Sensor function provided in the Active Test and monitor the air fuel ratio sensor (sensor 1) output voltage Click here. If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.
Read freeze frame data using the GTS. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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
INSPECT AIR FUEL RATIO SENSOR (SENSOR 1) (HEATER RESISTANCE)
Inspect the air fuel ratio sensor (sensor 1).
Tech Tips
Perform "Inspection After Repair" after replacing the air fuel ratio sensor (sensor 1).
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE AIR FUEL RATIO SENSOR (SENSOR 1) Click here |
| OK |
|
CHECK TERMINAL VOLTAGE (POWER SOURCE OF AIR FUEL RATIO SENSOR (SENSOR 1))
Disconnect the air fuel ratio sensor (sensor 1) connector.
Turn the power switch on (IG).
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | |||||||||
|---|---|---|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
CHECK HARNESS AND CONNECTOR (A/F HTR RELAY - AIR FUEL RATIO SENSOR (SENSOR 1)) Click here |
| OK |
|
CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR (SENSOR 1) - ECM)
Disconnect the air fuel ratio sensor (sensor 1) connector.
Disconnect the ECM connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
CLEAR DTC
Connect the GTS to the DLC3.
Turn the power switch on (IG).
Turn the GTS on.
Clear the DTCs.
Turn the power switch off and wait for at least 30 seconds.
| Result | ||
|---|---|---|
|
| NEXT |
|
CHECK WHETHER DTC OUTPUT RECURS (DTC P003012, P003013, P005012, P005013, P101A9E OR P103A9E)
Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
Enter the following menus: Powertrain / Engine / Trouble Codes.
Read the DTCs.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| A |
|
CHECK FOR INTERMITTENT PROBLEMS Click here |
| B |
|
REPLACE ECM Click here |
CHECK HARNESS AND CONNECTOR (A/F HTR RELAY - AIR FUEL RATIO SENSOR (SENSOR 1))
Remove the A/F HTR relay from the No. 1 engine room relay block and junction block assembly.
Disconnect the air fuel ratio sensor (sensor 1) connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
INSPECT A/F HTR RELAY
Inspect the A/F HTR relay.
| Result | |||
|---|---|---|---|
|
| NG |
|
REPLACE A/F HTR RELAY |
| OK |
|
CHECK TERMINAL VOLTAGE (POWER SOURCE OF A/F HTR RELAY)
| *1 | No. 1 Engine Room Relay Block and Junction Block Assembly |
| *2 | A/F HTR Relay |
Remove the A/F HTR relay from the No. 1 engine room relay block and junction block assembly.
Measure the voltage according to the value(s) in the table below.
| Standard Voltage | ||||||
|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (A/F HTR RELAY - AUXILIARY BATTERY) |
| OK |
|
CHECK HARNESS AND CONNECTOR (A/F HTR RELAY - BODY GROUND)
Remove the A/F HTR relay from the No. 1 engine room relay block and junction block assembly.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance | ||||||
|---|---|---|---|---|---|---|
|
| Result | |||
|---|---|---|---|
|
| OK |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR (A/F HTR RELAY - EFI-MAIN NO. 1 RELAY) |
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |