Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)


DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

CHECK TERMINAL VOLTAGE (+B OF HEATED OXYGEN SENSOR)

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - NO. 1 INTEGRATION RELAY)

DTC P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

DTC P0038 Oxygen Sensor Heater Control Circuit High (Bank 1 Sensor 2)

DTC P0057 Oxygen Sensor Heater Control Circuit Low (Bank 2 Sensor 2)

DTC P0058 Oxygen Sensor Heater Control Circuit High (Bank 2 Sensor 2)

DTC P102D O2 Sensor Heater Circuit Performance Bank 1 Sensor 2 Stuck ON

DTC P105D O2 Sensor Heater Circuit Performance Bank 2 Sensor 2 Stuck ON


DESCRIPTION

Refer to DTC P0136 (LandCruiser RM000000WBY0LYX_01.html).

HINT:
  1. Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
  2. 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. The ECM continues operating in fail-safe mode until the engine switch is turned off.

  3. 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.


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)


DTC No.
DTC Detection Condition
Trouble Area
P0037
P0057
The heated oxygen sensor heater (bank 1, 2 sensor 2) current is below 0.3 A (1 trip detection logic).
  1. Open in heated oxygen sensor heater (bank 1, 2 sensor 2) circuit
  2. Heated oxygen sensor heater (bank 1, 2 sensor 2)
  3. EFI No. 2 fuse
  4. ECM
P0038
P0058
The heated oxygen sensor (bank 1, 2 sensor 2) current is higher than 2 A (1 trip detection logic).
  1. Short in heated oxygen sensor (bank 1, 2 sensor 2) circuit
  2. Heated oxygen sensor heater (bank 1, 2 sensor 2)
  3. EFI No. 2 fuse
  4. ECM
P102D
P105D
The heated oxygen sensor heater (bank 1, 2 sensor 2) current is higher than a specified value while the heater is not operating (1 trip detection logic).
ECM
HINT:
  1. Bank 1 refers to the bank that includes the No. 1 cylinder.
  2. Bank 2 refers to the bank that does not include the No. 1 cylinder.
  3. Sensor 1 refers to the sensor closest to the engine assembly.
  4. 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 ECM supplements the heat from the exhaust with heat from a heating element inside the sensor.
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 and stores a DTC.

WIRING DIAGRAM

Refer to DTC P0136 (LandCruiser RM000000WBY0LYX_08.html).

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 GTS. 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.
1.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

  1. Inspect the heated oxygen sensor (LandCruiser RM000002RV6020X_01_0001.html).



NG
REPLACE HEATED OXYGEN SENSOR (LandCruiser RM000002W9N013X.html)
OK


2.CHECK TERMINAL VOLTAGE (+B OF HEATED OXYGEN SENSOR)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.1Gr-Fe Engine Control.Sfi System. Dtc P0037 Oxygen Sensor Heater Control Circuit Low (Bank 1 Sensor 2)

  1. Disconnect the heated oxygen sensor connector.

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

    Standard Voltage:
    for Automatic Transmission
    Tester Connection
    		Switch Condition
    		Specified Condition
    C27-2 (+B) - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    C145-2 (+B) - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    for Manual Transmission
    Tester Connection
    		Switch Condition
    		Specified Condition
    C27-2 (+B) - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    C28-2 (+B) - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    Text in Illustration
    *A
    		for Manual Transmission
    *B
    		for Automatic Transmission
    *a
    		Front view of wire harness connector
    (to Heated Oxygen Sensor Bank 1)
    *b
    		Front view of wire harness connector
    (to Heated Oxygen Sensor Bank 2)
    *c
    		Front view of wire harness connector
    (to Heated Oxygen Sensor Bank 2)

  1. Reconnect the heated oxygen sensor connector.



NG
Go to step 4
OK


3.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

  1. Disconnect the heated oxygen sensor connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance (Check for Open):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-1 (HT1B) - C37-18 (HT1B)
    		Always
    		Below 1 Ω
    C145-1 (HT2B) - C37-13 (HT2B)
    		Always
    		Below 1 Ω
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-1 (HT1B) - C37-12 (HT1B)
    		Always
    		Below 1 Ω
    C28-1 (HT2B) - C37-13 (HT2B)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-1 (HT1B) or C37-18 (HT1B) - Body ground
    		Always
    		10 kΩ or higher
    C145-1 (HT2B) or C37-13 (HT2B) - Body ground
    		Always
    		10 kΩ or higher
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-1 (HT1B) or C37-12 (HT1B) - Body ground
    		Always
    		10 kΩ or higher
    C28-1 (HT2B) or C37-13 (HT2B) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the ECM connector.

  1. Reconnect the heated oxygen sensor connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (LandCruiser RM00000329203TX.html)

4.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - NO. 1 INTEGRATION RELAY)

  1. Disconnect the heated oxygen sensor connector.

  1. Remove the No. 1 integration relay from the engine room relay block.

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

    Standard Resistance (Check for Open):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-2 (+B) - 1B-4
    		Always
    		Below 1 Ω
    C145-2 (+B) - 1B-4
    		Always
    		Below 1 Ω
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-2 (+B) - 1B-4
    		Always
    		Below 1 Ω
    C28-2 (+B) - 1B-4
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    for Automatic Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-2 (+B) or 1B-4 - Body ground
    		Always
    		10 kΩ or higher
    C145-2 (+B) or 1B-4 - Body ground
    		Always
    		10 kΩ or higher
    for Manual Transmission
    Tester Connection
    		Condition
    		Specified Condition
    C27-2 (+B) or 1B-4 - Body ground
    		Always
    		10 kΩ or higher
    C28-2 (+B) or 1B-4 - Body ground
    		Always
    		10 kΩ or higher

  1. Reinstall the No. 1 integration relay.

  1. Reconnect the heated oxygen sensor connector.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

CHECK ECM POWER SOURCE CIRCUIT (LandCruiser RM000001DN80BOX.html)