P0037
1GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P0037,P0038,P0057,P0058,P0141,P0161: Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
CAUTION / NOTICE / HINT
HINT
Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
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.
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 position 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 HO2 sensor heater to check the heater for malfunctions.
If the heater current is outside the normal range, the signal transmitted by the HO2 sensor becomes inaccurate. When the current in the HO2 sensor heater is outside the normal operating range, the ECM interprets this as a malfunction in the sensor heater and stores a DTC.
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 will determine that there is a malfunction in the HO2 sensor heater and set DTC P0141 and P0161.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All
P0037 and P0057
P0038 and P0058
P0141 and P0161
TYPICAL MALFUNCTION THRESHOLDS
P0037 and P0057
P0038 and P0058
P0141 and P0161 (Heater Performance Monitor Check)
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 ignition switch to ON and turn the Techstream on.
3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).
4. Turn the ignition switch off and wait for at least 30 seconds.
5. Turn the ignition switch to ON 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 NORMAL, the system is normal.
* 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 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
NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.
HINT
* Read freeze frame data using the Techstream. Freeze frame data record 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.
* When the values for the Data List items O2 Heater Curr Val B1S2 and O2 Heater Curr Val B2S2 are not 0 A, the heater is on.
* Refer to Data List / Active Test [O2 Heater B1S2, O2 Heater B2S2, O2 Heater Curr Val B1S2 and O2 Heater Curr Val B2S2] Data List / Active List.
PROCEDURE
1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
(a) Disconnect the Heated Oxygen (HO2) sensor connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Bank 1 Sensor 2):
Standard Resistance (Bank 2 Sensor 2):
(c) Reconnect the HO2 sensor connector.
NG -- REPLACE HEATED OXYGEN SENSOR Removal
OK -- Continue to next step.
2. INSPECT EFI RELAY
(a) Remove the EFI relay from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
(c) Reinstall the EFI relay.
NG -- REPLACE EFI RELAY
OK -- Continue to next step.
3. INSPECT ECM (HT1B OR HT2B VOLTAGE)
(a) Turn the ignition switch to ON.
(b) Measure the voltage between the terminals of the ECM connectors.
Standard Voltage:
HINT
* The HT1B means the heated oxygen sensor bank 1 sensor 2.
* The HT2B means the heated oxygen sensor bank 2 sensor 2.
NG -- CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM, HO2 SENSOR - EFI RELAY)
OK -- REPLACE ECM Removal
4. CHECK HARNESS AND CONNECTOR (HO2 SENSOR - ECM, HO2 SENSOR - EFI RELAY)
(a) Check the harness and connector between the ECM and HO2 sensor.
(1) Disconnect the HO2 sensor connector.
(2) Disconnect the ECM connector.
(3) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(4) Reconnect the HO2 sensor connector.
(5) Reconnect the ECM connector.
(b) Check the harness and connector between the HO2 sensor and EFI relay.
(1) Inspect the EFI No. 2 fuse.
Remove the EFI No. 2 fuse from the engine room relay block.
Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Reinstall the EFI No. 2 fuse.
(2) Disconnect the HO2 sensor connector.
(3) Remove the EFI relay from the engine room relay block.
(4) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(5) Reconnect the HO2 sensor connector.
(6) Reinstall the EFI relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM Removal