P0037

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


DESCRIPTION

- Refer to DTC P0136 P0136.

HINT
- When any of these DTCs are set, 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 ignition 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 cylinder No. 1.
- Bank 2 refers to the bank that does not include cylinder No. 1.
- 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 above 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 sets a DTC.

If a malfunction is detected, the ECM cuts off the current applied to the heater.

Example:

The ECM sets DTC P0038 or P0058 when the current in the HO2 sensor heater is more than 2 A. Conversely, when the heater current is less than 0.3 A, DTC P0037 or P0057 is set.

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 above the threshold value, the ECM determines that there is a malfunction in the HO2 sensor heater and sets DTC P0141 or P0161.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

P0037 and P0057 (Case 1)





P0037 and P0057 (Case 2)





P0038 and P0058





P0141 and P0161 (Case 1)





P0141 and P0161 (Case 2)





TYPICAL MALFUNCTION THRESHOLDS

P0037 and P0057 (Case 1)





P0037 and P0057 (Case 2)





P0038 and P0058





P0141 and P0161





COMPONENT OPERATING RANGE





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the tester ON.

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

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

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

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

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

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

9. Check the DTC judgment result [E].





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.

10. If the test result is UNKNOWN, enter the following menus: Powertrain / Engine and ECT / Trouble Code / Pending.

11. Read Pending DTCs.

HINT
If a pending DTC is output, the system is malfunctioning.

12. If the test result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear.

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

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 E35 or B19 Heated Oxygen (HO2) sensor connector.

(b) Measure the resistance of the HO2 sensor connector.

Standard resistance:

Bank 1





Standard resistance:

Bank 2





(c) Reconnect the HO2 sensor connector.

NG -- REPLACE HEATED OXYGEN SENSOR
OK -- Continue to next step.

2. CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR)





(a) Disconnect the E35 or B19 HO2 sensor connector.

(b) Turn the ignition switch to ON.

(c) Measure the voltage between the terminal of the E35 or B19 HO2 sensor connector and body ground.

Standard voltage:





(d) Reconnect the HO2 sensor connector.

OK -- CHECK WIRE HARNESS (HO2 SENSOR - ECM)
NG -- Continue to next step.

3. INSPECT INTEGRATION RELAY (EFI MAIN RELAY)





(a) Remove the integration relay from the engine room No. 1 relay block.

(b) Inspect the EFI MAIN fuse.

(1) Remove the EFI MAIN fuse from the integration relay.

(2) Measure the EFI MAIN fuse resistance.

Standard resistance:

Below 1 Ohms

(3) Reinstall the EFI MAIN fuse

(c) Inspect the EFI MAIN relay.

(1) Measure the EFI MAIN relay resistance.

Standard resistance:





(d) Reinstall the integration relay.

NG -- REPLACE INTEGRATION RELAY
OK -- Continue to next step.

4. CHECK WIRE HARNESS (HO2 SENSOR - EFI RELAY)

(a) Check the EFI No. 1 fuse.





(b) Disconnect the E35 or B19 HO2 sensor connector.

(c) Remove the integration relay from the engine room No. 1 relay block.

(d) Measure the resistance.

Standard resistance:





(e) Reconnect the HO2 sensor connector.

(f) Reinstall the integration relay.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- CHECK ECM POWER SOURCE CIRCUIT

5. CHECK WIRE HARNESS (HO2 SENSOR - ECM)





(a) Disconnect the E35 or B19 HO2 sensor connector.

(b) Disconnect the B30 ECM connector.

(c) Measure the resistance.

Standard resistance:





(d) Reconnect the HO2 sensor connector.

(e) Reconnect the ECM connector.

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 ignition switch to ON.

(c) Turn the tester ON.

(d) Clear DTCs DTC Check / Clear.

(e) Start the engine.

(f) Allow the engine to idle for 2 minutes or more.

(g) Select the following menu items: Powertrain / Engine and ECT / Trouble Code.

(h) Read DTCs.

Result:





B -- REPLACE ECM

A -- CHECK FOR INTERMITTENT PROBLEMS