P0037

3UR-FE ENGINE CONTROL: SFI SYSTEM: P0037, P0038, P0057, P0058, P0141, P0161: Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
P0161 - Oxygen Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

DESCRIPTION

- Refer to DTC P0136 P0136.

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.










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 (Case 1):





P0038 and P0058 (Case 2):





P0141 or P0161:





COMPONENT OPERATING RANGE





MONITOR RESULT

Refer to CHECKING MONITOR STATUS Mode 6 Data.

CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the engine switch on (IG) and turn the Techstream on.

3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

4. Turn the engine switch off and wait for at least 30 seconds.

5. Turn the engine switch on (IG) and turn the Techstream on [A].

6. Start the engine and idle it for 5 minutes or more [B].

7. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 3000 rpm for 1 minute [C].

8. Idle the engine for 5 minutes or more [D].

9. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [E].

10. Read the Pending DTCs.

HINT
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.

11. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

12. Input the DTC: P0037, P0038, P0057, P0058, P0141, or P0161.

13. Check the DTC judgment result.





HINT
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result shows INCOMPLETE or UNKNOWN, perform steps [B] through [E] again.

14. If no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0136 P0136.

INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following 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.
- 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.

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 Removal
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 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 Reading and Clearing Diagnostic Trouble Codes.

(e) Start the engine.

(f) Refer to the confirmation driving pattern.

(g) Read the output pending DTCs.

Result





B -- REPLACE ECM Removal

A -- CHECK FOR INTERMITTENT PROBLEMS Check For Intermittent Problems