P0037
2AZ-FXE ENGINE CONTROL: SFI SYSTEM: P0037, P0038, P0141, P102D: Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)
DESCRIPTION
Refer to DTC P0136 P0136.
HINT
- Sensor 2 refers to the sensor mounted behind the three-way catalytic converter and located far from the engine assembly.
- When any of these DTCs are set, the hybrid vehicle control ECU enters fail-safe mode. The hybrid vehicle control ECU turns off the heated oxygen sensor heater in fail-safe mode. Fail-safe mode continues until the power switch is turned off.
- The hybrid vehicle control ECU uses pulse width modulation to adjust the current through the heater. The heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.
HINT
- Bank 1 sensor 1 refers to the sensor closest to the engine assembly.
- Bank 1 sensor 2 refers to the sensor farthest away from the engine assembly.
MONITOR DESCRIPTION
The sensing portion of the heated oxygen 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 hybrid vehicle control ECU supplements the heat from the exhaust with heat from a heating element inside the sensor.
Heated Oxygen Sensor Heater Range Check (P0037, P0038 and P102D)
The hybrid vehicle control ECU monitors the current applied to the heated oxygen sensor heater to check the heater for malfunctions.
If the heater current is outside the normal range, the signal transmitted by the heated oxygen sensor becomes inaccurate. When the current in the heated oxygen sensor heater is outside the normal operating range, the hybrid vehicle control ECU interprets this as a malfunction in the sensor heater and stores a DTC.
Heated Oxygen Sensor Heater Performance (P0141)
After the accumulated heater ON time exceeds 100 seconds, the hybrid vehicle control ECU calculates the heater resistance using auxiliary battery voltage and the current applied to the heater. If the resistance is above the threshold value, the hybrid vehicle control ECU determines that there is a malfunction in the heated oxygen sensor heater and stores DTC P0141.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All
P0037 (Case 1)
P0037 (Case 2)
P0038
P0141
P102D
TYPICAL MALFUNCTION THRESHOLDS
P0037 (Case 1)
P0037 (Case 2)
P0038
P0141
P102D
MONITOR RESULT
- Refer to Checking Monitor Status Mode 6 Data.
CONFIRMATION DRIVING PATTERN
1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG) and turn the Techstream on.
3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Reading and Clearing Diagnostic Trouble Codes.
4. Turn the power switch off and wait for 30 seconds.
5. Turn the power switch on (IG) and turn the Techstream on [A].
6. Put the engine in inspection mode (maintenance mode) Component Tests and General Diagnostics.
7. Start the engine and idle it for 5 minutes or more [B].
8. With the vehicle stationary, depress the accelerator pedal and maintain an engine speed of 2500 rpm for 1 minute [C].
HINT
During charging 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 charging control has completed.
9. Idle the engine for 5 minutes or more [D].
10. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [E].
11. 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.
12. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
13. Input the DTC: P0037, P0038, P0141 or P102D.
14. 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 N/A, perform step [B] through [E] again.
15. 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
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. The hybrid vehicle control ECU 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.
- Change the fuel injection volume using the Control the Injection Volume function provided in the Active Test and monitor the heated oxygen sensor output voltage P0136. If the sensor output voltage does not change (almost no reaction) while performing the Active Test, the sensor may be malfunctioning.
PROCEDURE
1. INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
(a) Inspect the heated oxygen sensor Heated Oxygen Sensor.
NG -- REPLACE HEATED OXYGEN SENSOR Removal
OK -- Continue to next step.
2. CHECK TERMINAL VOLTAGE (POWER SOURCE)
(a) Disconnect the heated oxygen sensor connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Text in Illustration
(d) Reconnect the heated oxygen sensor connector.
NG -- INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN RELAY)
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - HYBRID VEHICLE CONTROL ECU)
(a) Disconnect the heated oxygen sensor connector.
(b) Disconnect the hybrid vehicle control ECU connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(d) Reconnect the heated oxygen sensor connector.
(e) Reconnect the hybrid vehicle control ECU connector.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK WHETHER DTC OUTPUT RECURS (DTC P0037, P0038, P0141 OR P0102D)
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG).
(c) Turn the Techstream on.
(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(e) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.
(f) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
(g) Read the pending DTCs.
Result:
B -- REPLACE HYBRID VEHICLE CONTROL ECU Removal
A -- CHECK FOR INTERMITTENT PROBLEMS Check for Intermittent Problems
5. INSPECT NO. 1 INTEGRATION RELAY (EFI MAIN RELAY)
(a) Inspect the No. 1 integration relay Inspection.
NG -- REPLACE NO. 1 INTEGRATION RELAY Removal
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - HEATED OXYGEN SENSOR)
(a) Remove the No. 1 integration relay from engine room relay block.
(b) Disconnect the No. 1 integration relay connector.
(c) Disconnect the heated oxygen sensor connector.
(d) Measure the resistance according to the value(s) in the table below.
Standard Resistance (Check for Open):
Standard Resistance (Check for Short):
(e) Reconnect the heated oxygen sensor connector.
(f) Reconnect the No. 1 integration relay connector.
(g) Reinstall the No. 1 integration relay.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - IGCT RELAY) P0031
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
8. CHECK HARNESS AND CONNECTOR (EFI MAIN RELAY - BODY GROUND) P0031
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (AUXILIARY BATTERY - EFI MAIN RELAY)