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    P2241    Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 2 Sensor 1)

DTC    P2242    Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 2 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)

DTC    P2255    Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 2 Sensor 1)

DTC    P2256    Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 2 Sensor 1)

for Preparation Click here


DESCRIPTION

HINT:
  1. Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
  2. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

Refer to DTC P2195 on page Click here.

DTC No.
DTC Detection Condition
Trouble Area
P2238
P2241
  1. Case 1:
Condition (a) or (b) continues for 5.0 seconds or more
(1 trip detection logic):
(a) AF+ voltage 0.5 V or less
(b) (AF+) - (AF-) = 0.1 V or less
  1. Case 2:
A/F sensor admittance: Less than 0.022 1/Ω
(2 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F relay
  5. A/F sensor heater and relay circuits
  6. ECM
P2239
P2242
AF+ voltage more than 4.5 V for 5.0 seconds or more
(2 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F relay
  5. A/F sensor heater and relay circuits
  6. ECM
P2252
P2255
AF- voltage 0.5 V or less for 5.0 seconds or more
(2 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F relay
  5. A/F sensor heater and relay circuits
  6. ECM
P2253
P2256
AF- voltage more than 4.5 V for 5.0 seconds or more
(2 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F relay
  5. A/F sensor heater and relay circuits
  6. ECM

HINT:
  1. DTCs P2238, P2239, P2252 and P2253 indicate malfunctions related to bank 1 A/F sensor circuit.
  2. DTCs P2241, P2242, P2255 and P2256 indicate malfunctions related to bank 2 A/F sensor circuit.
  3. Bank 1 refers to the bank that includes cylinder No. 1.
  4. Bank 2 refers to the bank that includes cylinder No. 2.


MONITOR DESCRIPTION

The Air-Fuel Ratio (A/F) sensor varies its output voltage in proportion to the air-fuel ratio. If the A/F sensor impedance (alternating current resistance) or output voltage deviates greatly from the standard range, the ECM determines that there is an open or short malfunction in the A/F sensor circuit.

WIRING DIAGRAM

Refer to DTC P2195 on page Click here.

INSPECTION PROCEDURE

HINT:
Intelligent tester only:
Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor function provided in the Active Test. The Control the Injection Volume for A/F Sensor function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F Sensor operation using the intelligent tester.
  1. Connect the intelligent tester to the DLC3.
  2. Start the engine and turn the tester ON.
  3. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
  4. On the tester, enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor.
  5. Perform the A/F Control operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
  6. Monitor the output voltages of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) displayed on the tester.

HINT:
  1. The Control the Injection Volume for A/F Sensor operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.
  1. Each sensor reacts in accordance with increases and decreases in the fuel injection volume.


Standard:

Tester Display
(Sensor)
Injection Volume
Status
Voltage
AFS B1 S1 or AFS B2 S1
(A/F)
+25 %
Rich
Less than 3.0
AFS B1 S1 or AFS B2 S1
(A/F)
-12.5 %
Lean
More than 3.35
O2S B1 S2 or O2S B2 S2
(HO2)
+25 %
Rich
 More than 0.55
O2S B1 S2 or O2S B2 S2
(HO2)
-12.5 %
Lean
Less than 0.4

NOTICE:
The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.


Case
A/F Sensor (Sensor 1)
Output Voltage
HO2 Sensor (Sensor 2)
Output Voltage
Main Suspected Trouble Areas
1
Injection Volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
-
Output Voltage
More than 3.35 V
Less than 3.0 V
A107708
Output Voltage
More than 0.55 V
Less than 0.4 V
A103186
2
Injection Volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
  1. A/F sensor
  2. A/F sensor heater
  3. A/F sensor circuit
Output Voltage
Almost
no reaction
A103185
Output Voltage
More than 0.55 V
Less than 0.4 V
A103186
3
Injection Volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
  1. HO2 sensor
  2. HO2 sensor heater
  3. HO2 sensor circuit
Output Voltage
More than 3.35 V
Less than 3.0 V
A107708
Output Voltage
Almost
no reaction
A103185
4
Injection volume
+25 %
-12.5 %
A103184
Injection Volume
+25 %
-12.5 %
A103184
  1. Injector
  2. Fuel pressure
  3. Gas leakage from exhaust system
    (Air-fuel ratio extremely lean or rich)
Output Voltage
Almost
no reaction
A103185
Output Voltage
Almost
no reaction
A103185
  1. Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the output voltages of both the A/F and HO2 sensors.
  2. To display the graph, enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2.

HINT:
  1. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when malfunctions are 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 ich, and other data from the time the malfunction occurred.

1.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
A085152E10

  1. Disconnect the E68 or E65 Air-Fuel Ratio (A/F) sensor connector.

  1. Measure the resistance between the terminals of the A/F sensor connector.

    Standard resistance (Bank 1 sensor 1):
    Tester Connection
    		Specified Condition
    HA1A (1) - +B (2)
    		1.8 to 3.4 Ω at 20°C (68°F)
    HA1A (1) - A1A- (4)
    		10 kΩ or higher

    Standard resistance (Bank 2 sensor 1):
    Tester Connection
    		Specified Condition
    HA2A (1) - +B (2)
    		1.8 to 3.4 Ω at 20°C (68°F)
    HA2A (1) - A2A- (4)
    		10 kΩ or higher

  1. Reconnect the A/F sensor connector.



NG
REPLACE AIR FUEL RATIO SENSOR
OK


2.INSPECT A/F RELAY
B016200E02

  1. Remove the A/F relay from the engine room No. 2 relay block.

  1. Measure the resistance of the A/F relay.

    Standard resistance:
    Tester Connection
    		Specified Condition
    3 - 5
    		10 kΩ or higher
    3 - 5
    		Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)

  1. Reinstall the A/F relay.



NG
REPLACE A/F RELAY
OK


3.CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
A107711E03

  1. Disconnect the E68 and E65 A/F sensor connector.

  1. Turn the engine switch on (IG).

  1. Measure the voltage between the +B terminal of the A/F sensor connector and body ground.

    Standard voltage:
    Tester Connection
    		Specified Condition
    +B (E68-2) - Body ground
    		9 to 14 V
    +B (E65-2) - Body ground
    		9 to 14 V

  1. Turn the engine switch off.

  1. Disconnect the E45 ECM connector.

  1. Measure the resistance.

    Standard resistance (Check for open):
    Tester Connection
    		Specified Condition
    HA1A( E68-1) - HA1A (E45-6)
    		Below 1 Ω
    A1A+ (E68-3) - A1A+ (E45-18)
    		Below 1 Ω
    A1A- (E68-4) - A1A- (E45-17)
    		Below 1 Ω
    HA2A (E65-1) - HA2A (E45-4)
    		Below 1 Ω
    A2A+ (E65-3) - A2A+ (E45-28)
    		Below 1 Ω
    A2A- (E65-4) - A2A- (E45-27)
    		Below 1 Ω

    Standard resistance (Check for short):
    Tester Connection
    		Specified Condition
    HA1A( E68-1) or HA1A (E45-6) - Body ground
    		10 kΩ or higher
    A1A+ (E68-3) or A1A+ (E45-18) - Body ground
    		10 kΩ or higher
    A1A- (E68-4) or A1A- (E45-17) - Body ground
    		10 kΩ or higher
    HA2A (E65-1) or HA2A (E45-4) - Body ground
    		10 kΩ or higher
    A2A+ (E65-3) or A2A+ (E45-28) - Body ground
    		10 kΩ or higher
    A2A- (E650-4) or A2A- (E45-27) - Body ground
    		10 kΩ or higher

  1. Reconnect the ECM connector.



  1. Reconnect the A/F sensor connector.


    A103833E08



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE ECM