P0057
3UR-FE ENGINE CONTROL: SFI SYSTEM: P0037: Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
DTC P0037 - Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
DTC P0038 - Oxygen Sensor Heater Control Circuit High (Bank 1 Sensor 2)
DTC P0057 - Oxygen Sensor Heater Control Circuit Low (Bank 2 Sensor 2)
DTC P0058 - Oxygen Sensor Heater Control Circuit High (Bank 2 Sensor 2)
DTC P0141 - Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
DTC P0161 - Oxygen Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)
DESCRIPTION
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 TWC is used. For the most efficient use of the TWC, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel level. For the purpose of helping the ECM to deliver accurate air-fuel ratio control, a Heated Oxygen (HO2) sensor is used.
The HO2 sensor is located behind the TWC, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).
When the air-fuel ratio becomes lean, the oxygen concentration in the exhaust gas is rich. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is lean (low voltage, i.e. below 0.45 V).
Conversely, when the air-fuel ratio is richer than the stoichiometric air-fuel level, the oxygen concentration in the exhaust gas becomes lean. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is rich (high voltage, i.e. higher than 0.45 V). The HO2 sensor has the property of changing its output voltage drastically when the air-fuel ratio is close to the stoichiometric level.
The ECM uses the supplementary information from the HO2 sensor to determine whether the air-fuel ratio after the TWC is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the HO2 sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air-fuel ratio control.
HINT:
- When any of these DTCs is stored, the ECM enters fail-safe mode. The ECM turns off the Heated Oxygen (HO2) Sensor heater in fail-safe mode. Fail-safe mode continues until the engine switch is turned off.
- The ECM provides a pulse width modulated control circuit to adjust the current through the heater. The HO2 sensor heater circuit uses a relay on the +B side of the circuit.
HINT:
- Bank 1 refers to the bank that includes the No. 1 cylinder.
- 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.
MONITOR DESCRIPTION
The sensing portion of the Heated Oxygen (HO2) sensor has a zirconia element which is used to detect the oxygen concentration in the exhaust gas. If the zirconia element is at the appropriate temperature, and the difference between the oxygen concentrations surrounding the inside and outside surfaces of the sensor is large, the zirconia element generates voltage signals. In order to increase the oxygen concentration detecting capacity of the zirconia element, the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor.
Heated oxygen sensor heater range check (P0037, P0038, P0057 and P0058):
The ECM monitors the current applied to the O2 sensor heater to check the heater for malfunctions. If the current is below the threshold value, the ECM determines that there is an open circuit in the heater. If the current is higher than the threshold value, the ECM determines that there is a short circuit in the heater.
The ECM constantly monitors the current applied to the heater. If the ECM detects an open or short circuit, the ECM turns the MIL on and stores a DTC.
If a malfunction is detected, the ECM cuts off the current applied to the heater.
Example:
The ECM stores DTC P0038 or P0058 when the current in the HO2 sensor heater is higher than 2 A. Conversely, when the heater current is below 0.3 A, DTC P0037 or P0057 is stored.
Heated oxygen sensor heater performance (P0141 and P0161):
After the accumulated heater ON time exceeds 100 seconds, the ECM calculates the heater resistance using the battery voltage and the current applied to the heater.
If the resistance is higher than the threshold value, the ECM determines that there is a malfunction in the HO2 sensor heater and stores DTC P0141 or P0161.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All:
P0037 and P0057:
P0038 and P0058 (Condition A):
P0038 and P0058 (Condition B):
P0141 or P0161 (Condition A):
P0141 or P0161 (Condition B):
TYPICAL MALFUNCTION THRESHOLDS
P0037 and P0057:
P0038 and P0058 (Criteria A):
P0038 and P0058 (Criteria B):
P0141 or P0161:
COMPONENT OPERATING RANGE
WIRING DIAGRAM
CONFIRMATION DRIVING PATTERN
HINT:
- This confirmation driving pattern is used in the "Perform Confirmation Driving Pattern" procedure of the following diagnostic troubleshooting procedure.
- Performing this confirmation driving pattern will activate the Heated Oxygen (HO2) sensor monitor (the catalyst monitor is performed simultaneously). This is very useful for verifying the completion of a repair.
NOTE:
This test will not be completed if the vehicle is driven under absolutely constant speed conditions such as with cruise control activated.
1 Connect the Techstream to the DLC3.
2 Turn the engine switch on (IG).
3 Warm-up the engine until the engine coolant temperature is 75°C (167°F) or higher [A].
4 Drive the vehicle at between 60 km/h and 120 km/h (40 mph and 75 mph) for at least 10 minutes [B].
5 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].
6 Turn the Techstream on.
7 Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
8 Input DTCs: P0136, P0137, P0138, P0139, P0156, P0157, P0158 and P0159.
9 Check the DTC monitor is NORMAL. If DTC monitor is INCOMPLETE, perform the drive pattern adding the vehicle speed and using the second gear to decelerate the vehicle.
INSPECTION PROCEDURE
HINT:
- Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
- 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. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
(a) Disconnect the C17 or C18 heated oxygen (HO2) sensor connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE HEATED OXYGEN SENSOR
OK -- Continue to next step.
2. CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR)
(a) Disconnect the C17 or C18 HO2 sensor connector.
(b) Turn the engine switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Result
B -- CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM)
A -- Continue to next step.
3. INSPECT INTEGRATION RELAY (EFI)
(a) Remove the integration relay from the engine room relay block.
(b) Inspect the EFI MAIN fuse.
(1) Remove the EFI MAIN fuse from the integration relay.
(2) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(3) Reinstall the EFI MAIN fuse.
(c) Inspect the EFI relay.
(1) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPLACE INTEGRATION RELAY (EFI)
OK -- Continue to next step.
4. CHECK HARNESS AND CONNECTOR (HO2 SENSOR - INTEGRATION RELAY)
(a) Check the EFI NO. 2 fuse.
(1) Remove the EFI NO. 2 fuse from the engine room relay block.
(2) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(3) Reinstall the EFI NO. 2 fuse.
(b) Disconnect the C17 or C18 HO2 sensor connector.
(c) Remove the integration relay from the engine room relay block.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- CHECK ECM POWER SOURCE CIRCUIT
5. CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM)
(a) Disconnect the C17 or C18 HO2 sensor connector.
(b) Disconnect the C53 ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. CHECK WHETHER DTC OUTPUT RECURS
(a) Connect the Techstream to the DLC3.
(b) Turn the engine switch on (IG).
(c) Turn the Techstream on.
(d) Clear DTCs DTC Check / Clear.
(e) Start the engine.
(f) Allow the engine to idle for 2 minutes or more.
(g) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(h) Read DTCs.
Result
B -- REPLACE ECM
A -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems