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    P0141    Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

DTC    P0161    Oxygen Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

для подготовки Нажмите здесь


DESCRIPTION

The heated oxygen sensor is used to monitor oxygen concentration in the exhaust gas. For optimum catalytic converter operation, the air-fuel mixture must be maintained near the ideal stoichiometric air-fuel ratio. The heated oxygen sensor output voltage changes suddenly in the vicinity of the stoichiometric air-fuel ratio. The ECM adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The heated oxygen sensor generates a voltage between 0.1 and 0.9 V in response to oxygen concentration in the exhaust gas.
If the oxygen concentration in the exhaust gas increases, the air-fuel ratio is called LEAN. The heated oxygen sensor voltage drops below 0.45 V and the heated oxygen sensor informs the ECM of the LEAN condition.
If oxygen is not in the exhaust gas, the air-fuel ratio is called RICH. The heated oxygen sensor voltage increases above 0.45 V and the heated oxygen sensor informs the ECM of the RICH condition.

A088111E02

УКАЗАНИЕ:
  1. Sensor 2 refers to the sensor mounted behind the Three-Way Catalytic Converter (TWC) and located far from the engine assembly.
  2. The ECM has a pulse width modulated control circuit to adjust current through the heater. The heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.
  3. 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 engine switch is turned off.


A149597E02


DTC No.
DTC Detection Condition
Trouble Area
P0037
P0057
Heated oxygen sensor heater current is below 0.25 A when heater operates with +B greater than 11.5 V
(1 trip detection logic)
  1. Open or short in heated oxygen sensor heater circuit
  2. Heated oxygen sensor heater
  3. EFI MAIN 2 relay
  4. ECM
P0038
P0058
Heater current exceeds 2 A when heater operates
(1 trip detection logic)
  1. Open or short in heated oxygen sensor heater circuit
  2. Heated oxygen sensor heater
  3. EFI MAIN 2 relay
  4. ECM
P0141
P0161
Cumulative heater resistance correction value exceeds threshold
(2 trip detection logic)
  1. Open or short in HO2 sensor heater circuit
  2. HO2 sensor heater
  3. EFI MAIN 2 relay
  4. 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. If the zirconia element is at the proper temperature and the difference of the oxygen concentration between the inside and outside surface of the sensor is large, the zirconia element will generate voltage signals. In order to increase the oxygen concentration detecting capacity in the zirconia element, the ECM supplements the heat from the exhaust with heat from a heating element inside the sensor. When the current in the heated oxygen sensor heater is out of the standard operating range, the ECM interprets this as a fault in the heated oxygen sensor heater. The ECM illuminates the MIL and sets a DTC.
Normally, the heated oxygen sensor heater current is 0.4 to 1.0 A.
Example:
The ECM will set a high current DTC if the current in the sensor is more than 2 A. Similarly, the ECM will set a low current DTC if the current is less than 0.25 A.
The monitor runs if the engine is started and run at idle for 9 minutes or more.

WIRING DIAGRAM


A152752E01


INSPECTION PROCEDURE

УКАЗАНИЕ:
  1. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.
  2. Bank 1 refers to the bank that includes No. 1 cylinder.
  3. Bank 2 refers to the bank that does not include No. 1 cylinder.
  4. No. 1 cylinder is located in the front part of the engine, opposite the transmission.
  5. Sensor 1 refers to the sensor closest to the engine body.
  6. Sensor 2 refers to the sensor farthest away from the engine body.

1.INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
A117841E18

  1. Disconnect the L49 and L50 sensor connectors.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 (HT1B) - 2 (+B)
    		Always
    		11 to 16 Ω
    1 (HT2B) - 2 (+B)
    		Always
    		11 to 16 Ω
    1 (HT1B) - 4 (E2)
    		Always
    		10 kΩ or higher
    1 (HT2B) - 4 (E2)
    		Always
    		10 kΩ or higher



NG
REPLACE HEATED OXYGEN SENSOR (Нажмите здесь)
OK


2.CHECK TERMINAL VOLTAGE (+B OF HO2 SENSOR)
A149595E01

  1. Disconnect the L49 or L50 sensor connector.

  1. Turn the engine switch on (IG).

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

    Standard voltage:
    Terminal Connections
    		Switch Condition
    		Specified Condition
    L50-2 (+B) - Body ground
    		Engine switch on (IG)
    		11 to 14 V
    L49-2 (+B) - Body ground
    		Engine switch on (IG)
    		11 to 14 V



NG
Перейдите к шагу 4
OK


3.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
A107687E32

  1. Disconnect the L49 and L50 sensor connectors.

  1. Disconnect the A13 ECM connector.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    L50-1 (HT1B) - A13-4 (HT1B)
    		Always
    		Below 1 Ω
    L49-1 (HT2B) - A13-3 (HT2B)
    		Always
    		Below 1 Ω
    L50-1 (HT1B) or A13-4 (HT1B) - Body ground
    		Always
    		10 kΩ or higher
    L49-1 (HT2B) or A13-3 (HT2B) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Нажмите здесь)  

4.CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - EFI MAIN 2 RELAY)
A149598E02

  1. Disconnect the L49 and L50 sensor connectors.

  1. Remove the EFI MAIN 2 relay from the engine room No. 2 relay block.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    EFI MAIN2 relay (3) - L50-2 (+B)
    		Always
    		Below 1 Ω
    EFI MAIN2 relay (3) - L49-2 (+B)
    		Always
    		Below 1 Ω
    EFI MAIN2 relay (3) or L50-2 (+B) - Body ground
    		Always
    		10 kΩ or higher
    EFI MAIN2 relay (3) or L49-2 (+B) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

CHECK ECM POWER SOURCE CIRCUIT (Нажмите здесь)