DTC P2237, DTC P22378, DTC P2239, DTC P2252, DTC P2253

DTC P2237 Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)

DTC P2238 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)

DTC P2239 Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 1 Sensor 1)

DTC P2252 Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 1 Sensor 1)

DTC P2253 Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 1 Sensor 1)

 

Description

 

HINT:

  1. For more information on the A/F sensor and TOYOTA D-CAT*, refer to the following procedures.
  2. These DTCs are related to the A/F sensor, although the titles say oxygen sensor.
  3. If P2237, P2238 and/or P2239 is present, refer to the DTC table for TOYOTA D-CAT system.
  4. These DTCs are recorded when A/F sensor has malfunction, although the titles say oxygen sensor.

*: Diesel Clean Advanced Technology.

 

The A/F sensor has the characteristic of providing output voltage which is proportional to the existing air- fuel ratio. The A/F sensor output voltage*1 is used to provide the ECM with feedback to control the air-fuel ratio.
The A/F sensor is located after the DPNR*2 catalytic converter. This sensor has been developed based on the structure and technology of the sensor used for gasoline engines. The cover portion of the sensor has been changed for use in the diesel engine with TOYOTA D-CAT in order to eliminate the influence of the sensor temperature and particulate matter (PM).
In order to reduce both PM and nitrogen oxides (NOx), the ECM adjusts the air-fuel ratio to slightly RICH (LEAN compared with a stoichiometric air-fuel ratio) based on signals from the A/F sensor. When the ECM exercises DPNR catalyst regeneration by adding fuel using the exhaust fuel addition injector, the air-fuel ratio is also properly adjusted through the sensor.
*1: The voltage value changes inside the ECM only.
*2: Diesel Particulate-NOx Reduction system.


Description DTC P2237, DTC P22378, DTC P2239, DTC P2252, DTC P2253

HINT:

The ECM provides a pulse width modulated control circuit to adjust current through the heater. The A/F sensor heater circuit uses a relay on the B+ side of the circuit.

 


Description DTC P2237, DTC P22378, DTC P2239, DTC P2252, DTC P2253

Toyota fault code list 2AD-FHV DTC P2237, DTC P22378, DTC P2239, DTC P2252, DTC P2253

DTC No. DTC Detection Condition Trouble Area
P2237 ECM internal error (5.0 seconds)
(1 trip detection logic)		 ECM
P2238
P2252		 A/F sensor circuit low (bank 1 sensor 1)
AF+ is less than 1.0 V for 5.0 seconds or more
(1 trip detection logic)		 Main trouble area: Open in A/F sensor circuit
  1. Open or short in A/F sensor circuit
  2. A/F sensor
  3. A/F sensor heater
  4. A/F sensor heater relay
  5. A/F sensor heater and relay circuit
  6. ECM
P2239
P2253		 A/F sensor circuit high (bank 1 sensor 1)
AF+ is more than 4.0 V for 5.0 seconds or more
(1 trip detection logic)		 Main trouble area: Short in A/F sensor circuit
  1. Open or short in A/F sensor circuit
  2. A/F sensor
  3. A/F sensor heater
  4. A/F sensor heater relay
  5. A/F sensor heater and relay circuit
  6. ECM

 

Monitor description

The A/F sensor varies its voltage output in proportion to the air-fuel ratio. If impedance (alternating current resistance) or voltage output of the sensor deviates greatly from the standard range, the ECM interprets this as an open or short malfunction of the A/F sensor circuit.

Wiring diagram

Refer to DTC P0031.

Inspection procedure

 

NOTICE:

 

After replacing the ECM, the new ECM needs registration and initialization.

 

1.CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P2237)

 

  1. Connect the intelligent tester to the DLC3.

  2. Turn the ignition switch on (IG) and turn the tester ON.

  3. Enter the following menus: Powertrain / Engine and ECT / DTC.

  4. Read DTCs.

     

    Result:
    Display (DTC Output) Proceed to
    P2237 and P2238, P2239, P2252 and/or P2253 A
    P2237 B

 

  B  
REPLACE ECM
 
A  
   
2.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

Inspect air fuel ratio sensor (heater resistance). DTC P2237, DTC P22378, DTC P2239, DTC P2252, DTC P2253

  1. Disconnect the B62 A/F sensor connector.

  2. Measure the resistance of the terminals of the A/F sensor.

     

    Standard resistance:

    Tester Connection Condition Specified Condition
    B62-1 (HAF2) - B62-2 (+B) 20°C (68°F) 1.8 to 3.4 ?

  3. Reconnect the A/F sensor connector.

 

  NG  
REPLACE AIR FUEL RATIO SENSOR
 
OK  
   
3.INSPECT INTEGRATION RELAY (A/F RELAY)

Inspect integration relay (a/f relay). DTC P2237, DTC P22378, DTC P2239, DTC P2252, DTC P2253

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

  2. Inspect the A/F fuse.

    1. Remove the A/F fuse from the integration relay.

    2. Measure the resistance of the fuse.

       

      Standard resistance:

      Below 1 ?

    3. Reinstall the A/F fuse.

     

  3. Inspect the A/F relay.

    1. Measure the A/F relay resistance.

       

      Standard resistance:

      Tester Connection Specified Condition
      1B-8 - 1C-1 10 k? or higher
      1B-8 - 1C-1 Below 1 ? (Apply battery voltage to terminals 1B-6 and 1B-7)

    2. Reinstall the integration relay.

 

  NG  
REPLACE INTEGRATION RELAY
 

 

OK  
   
4.CHECK WIRE HARNESS (A/F SENSOR - ECM)

Check wire harness (a/f sensor - ecm). DTC P2237, DTC P22378, DTC P2239, DTC P2252, DTC P2253

  1. Disconnect the B62 A/F sensor connector.

  2. Disconnect the B32 ECM connector.

  3. Measure the resistance of the wire harness side connector.

     

    Standard resistance:

    Tester Connection Specified Condition
    B62-1 (HAF2) - B32-104 (HAF2) Below 1 ?
    B62-1 (HAF2) or B32-104 (HAF2) - Body ground 10 k? or higher

  4. Reconnect the A/F sensor connector.

  5. Reconnect the ECM connector.

 

  NG  
REPAIR OR REPLACE HARNESS AND CONNECTOR
 
OK  
   
REPLACE ECM