Toyota Venza manuals

Toyota Venza: Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2) (P0037,P0038,P0141,P102D)

Toyota Venza Service Manual / 1ar-fe Engine Control / Sfi System / Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2) (P0037,P0038,P0141,P102D)

DESCRIPTION

Refer to DTC P0136 (See page ).


HINT:

  • When any of these DTCs are stored, the ECM enters fail-safe mode. The ECM turns off the heated oxygen 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 heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.

DTC No.

DTC Detection Condition

Trouble Area

P0037

The heater current less than the specified value while the heater is operating (1 trip detection logic).

  • Open in heated oxygen sensor (bank 1 sensor 2) heater circuit
  • Heated oxygen sensor (bank 1 sensor 2)
  • EFI MAIN No. 2 relay
  • ECM

P0038

Heated oxygen sensor heater current reaches high limit (1 trip detection logic).

  • Short in heated oxygen sensor (bank 1 sensor 2) heater circuit
  • Heated oxygen sensor (bank 1 sensor 2)
  • EFI MAIN No. 2 relay
  • ECM

P0141

The cumulative heater resistance correction value exceeds the threshold (2 trip detection logic).

  • Open or short in heated oxygen sensor (bank 1 sensor 2) heater circuit
  • Heated oxygen sensor (bank 1 sensor 2) heater
  • EFI MAIN No. 2 relay
  • ECM

P102D

The heater current is higher than the specified value while the heater is not operating (1 trip detection logic).

ECM

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 ECM 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 ECM 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 ECM 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 ECM calculates the heater resistance using 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 heated oxygen sensor heater and stores DTC P0141.

MONITOR STRATEGY

Related DTCs

P0037: Heated Oxygen Sensor Heater (Bank 1 Sensor 2) range check (Low Current)

P0038: Heated Oxygen Sensor Heater (Bank 1 Sensor 2) range check (High Current)

P0141: Heated Oxygen Sensor Heater (Bank 1 Sensor 2) Performance

P102D: Heated Oxygen Sensor Heater (Bank 1 Sensor 2) Performance

Required Sensors/Components (Main)

Heated oxygen sensor heater (bank 1 sensor 2)

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous: P0037, P0038, P102D

Once per driving cycle: P0141

Duration

0.5 seconds: P0037

Within 3 seconds: P0038

10 seconds: P0141

0.5 seconds: P102D

MIL Operation

Immediate: P0037, P0038, P102D

2 driving cycles: P0141

Sequence of Operation

None

TYPICAL ENABLING CONDITIONS

P0037 (Case 1)

Monitor runs whenever the following DTCs are not stored

None

All of the following conditions are met

-

Battery voltage

10.5 V or higher

Engine

Running

Starter

OFF

Catalyst active air fuel ratio control

Not operating

Time after heater on

10 seconds or more

Learned heater off current operation

Completed

Learned heater off current operation

Succeeded

Heated oxygen sensor heater high current fail (P0038)

Not detected

Heater on current - learned heater off current

0.3 A or less

Command to heater output

ON

P0037 (Case 2)

Monitor runs whenever the following DTCs are not stored

None

All of the following conditions are met

-

Battery voltage

10.5 V or higher

Engine

Running

Starter

OFF

Catalyst active air fuel ratio control

Not operating

Time after heater on

10 seconds or more

Learned heater off current operation

Completed

Heater off current

Higher than 3.5 A

Heater current detected by heater monitor IC

4 A or higher

Heated oxygen sensor heater high current fail (P0038)

Not detected

P0038

Monitor runs whenever the following DTCs are not stored

None

All of the following conditions are met

-

Battery voltage

10.5 V or higher

Engine

Running

Starter

OFF

Catalyst active air fuel ratio control

Not operating

Time after heater on

10 seconds or more

Learned heater off current operation

Completed

Heater current detected by heater monitor IC

4 A or higher

Command to heater output

ON

P0141

Monitor runs whenever the following DTCs are not stored

None

All of the following conditions are met

-

Heated oxygen sensor heater circuit fail (P0037, P0038 and P101D)

Not detected

Battery voltage

10.5 V or higher

Fuel cut

OFF

Time after fuel cut on to off

30 seconds or more

Accumulated heater on time

100 seconds or more

Learned heater off current operation

Completed

Duration that rear heated oxygen sensor impedance is less than 15 kΩ

2 seconds or more

P102D

Monitor runs whenever the following DTCs are not stored

None

All of the following conditions are met

-

Battery voltage

10.5 V or higher

Engine

Running

Starter

OFF

Catalyst active air fuel ratio control

Not operating

Time after heater on

10 seconds or more

Learned heater off current operation

Completed

Oxygen sensor heater low current fail (P0037)

Not detected

Oxygen sensor heater high current fail (P0038)

Not detected

Command to heater output

OFF

Heater off current

Higher than 3.5 A

Heater current detected by heater monitor IC

4 A or higher

TYPICAL MALFUNCTION THRESHOLDS

P0037 (Case 1)

Heater on current - Learned heater off current

0.3 A or less

P0037 (Case 2)

Heater on current

1 A or less

P0038

Heater current detected by heater monitor IC

4 A or higher

Command to heater output

ON

P0141

Heater resistance

Varies with sensor element temperature (Example: Higher than 23 Ω)

P102D

Heater on current

Higher than 1 A

MONITOR RESULT

  • Refer to Checking Monitor Status (See page ).

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 procedure) (See page ).

  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 / Trouble Codes [E].
  10. Read 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 / Utility / All Readiness.
  12. Input the DTC: P0037, P0038, P0141 or P102D.
  13. Check the DTC judgment result.

    Techstream Display

    Description

    NORMAL

    • DTC judgment completed
    • System normal

    ABNORMAL

    • DTC judgment completed
    • System abnormal

    INCOMPLETE

    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A

    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
  14. If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [E] again.
  15. If no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    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 (See page ).


CAUTION / NOTICE / HINT

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 ECM 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.
  • Sensor 1 refers to the sensor closest to the engine assembly.
  • Sensor 2 refers to the sensor farthest away from the engine assembly.
  • 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 (See page ). 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 (See page ).


HINT:

Perform "Inspection After Repair" after replacing the heated oxygen sensor (See page ).



NG

REPLACE HEATED OXYGEN SENSOR


OK

2.

CHECK TERMINAL VOLTAGE (POWER SOURCE)

(a) Disconnect the heated oxygen sensor connector.


(b) Turn the ignition switch to ON.

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

B57-2 (+B) - Body ground

Ignition switch ON

11 to 14 V

Text in Illustration

*a

Front view of wire harness connector

(to Heated Oxygen Sensor)


NG

GO TO STEP 5


OK

3.

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

(a) Disconnect the heated oxygen sensor connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

B57-1 (HT1B) - B58-41 (HT1B)

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

B57-1 (HT1B) or B58-41 (HT1B) - Body ground

Always

10 kΩ or higher


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR


OK

4.

CHECK WHETHER DTC OUTPUT RECURS (DTC P0037, P0038, P0141 OR P102D)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear the DTCs (See page ).


(e) Turn the ignition switch off and wait for at least 30 seconds.

(f) Allow the vehicle to drive in accordance with the driving pattern described in the Confirmation Driving Pattern.

(g) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.

(h) Read the Pending DTCs.

Result

Proceed to

DTC P0037, P0038, P0141 or P102D is output

A

DTC is not output

B


A

REPLACE ECM


B

CHECK FOR INTERMITTENT PROBLEMS

5.

INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY (EFI MAIN NO. 2 RELAY)

(a) Inspect the EFI MAIN No. 2 relay (See page ).



NG

REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY


OK

6.

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - EFI MAIN NO. 2 RELAY)

(a) Disconnect the heated oxygen sensor connector.

(b) Remove the engine room junction block assembly from the engine room relay block.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance (Check for Open):

Tester Connection

Condition

Specified Condition

B57-2 (+B) - 1F-9

Always

Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection

Condition

Specified Condition

B57-2 (+B) or 1F-9 - Body ground

Always

10 kΩ or higher


OK

REPAIR OR REPLACE HARNESS OR CONNECTOR (BATTERY - EFI MAIN NO. 2 RELAY)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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