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

Refer to DTC P2195 (Click here).

DTC No.
DTC Detection Condition
Trouble Area
P2238
P2241
A/F sensor circuit low (bank 1 sensor 1)

HINT:
Main trouble area

  1. Open in A/F sensor circuit
Condition (a) continues for 5.0 sec. or more:
(a) AF+ voltage is 0.5 V or less
  1. Open or short in A/F sensor circuit
  2. A/F sensor
  3. A/F sensor heater
  4. A/F relay
  5. A/F sensor heater and A/F relay circuit
  6. ECM
Condition (a) continues for 5.0 sec. or more:
(b) (AF+) - (AF-) = 0.1 V or less
P2239
P2242
A/F sensor circuit high (bank 1 sensor 1)
(2 trip detection logic)

HINT:
Main trouble area

  1. Short in A/F sensor circuit
Condition (a) continues for 5.0 sec. or more:
AF+ voltage is greater than 4.5 V
  1. Open or short in A/F sensor circuit
  2. A/F sensor
  3. A/F sensor heater
  4. A/F heater relay
  5. A/F sensor heater and A/F relay circuit
  6. ECM
Condition (a) continues for 5.0 sec. or more:
(b) (AF+) - (AF-) = greater than 0.8 V
P2252
P2255
Condition (a) continues for 5.0 sec. or more:
AF- voltage is 0.5 V or less
(2 trip detection logic)
  1. Open or short in A/F sensor circuit
  2. A/F sensor
  3. A/F sensor heater
  4. A/F relay
  5. A/F sensor heater and A/F relay circuit
  6. ECM
P2253
P2256
Condition (a) continues for 5.0 sec. or more:
AF- voltage is greater than 4.5 V

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 the No. 1 cylinder.
  4. Bank 2 refers to the bank that includes the No. 2 cylinder.


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 (Click here).

INSPECTION PROCEDURE

HINT:
Intelligent tester only:
Malfunctioning areas can be found by performing the Active Test "Control the injection volume for A/F sensor" operation. The "Control the injection volume for A/F sensor" operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble areas are malfunctioning or not.
(a) Perform Active Test using the intelligent tester.

HINT:
"Control the injection volume for A/F sensor" is an Active Test which changes the injection volume to -12.5% or +25%.

(1) Control the intelligent tester to the DLC3.
(2) Start the engine and turn the tester ON.
(3) Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
(4) Enter the following menus on the intelligent tester: Powertrain / Engine and ECT / Active Test / Control the injection volume for A/F sensor.
(5) Enter the following monitor items: AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2.
(6) Perform the "Control the injection volume for A/F sensor" operation with the engine in an idling condition (press the right or left button).

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 B1S1 or AFS B2S1
(A/F)
+25%
Rich
Less than 3.0
AFS B1S1 or AFS B2S1
(A/F)
-12.5%
Lean
More than 3.35
O2S B1S2 or O2S B2S2
(heated oxygen sensor)
+25%
Rich
 More than 0.55
O2S B1S2 or O2S B2S2
(heated oxygen sensor)
-12.5%
Lean
Less than 0.4

NOTICE:
The A/F sensor output has a few seconds of delay and the heated oxygen sensor output has approximately 20 seconds of delay.


Case
A/F Sensor (Sensor 1)
Output Voltage
Heated Oxygen 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. Heated oxygen sensor
  2. Heated oxygen sensor heater
  3. Heated oxygen 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
The following A/F control procedure enables technician to check and graph the output voltages of both the A/F sensor and heated oxygen sensor.

HINT:
  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. These DTCs are related to the A/F sensor.
  3. These DTCs are recorded when A/F sensor has a malfunction, although the caption is heated oxygen sensor.

1.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
A085152E15

  1. Disconnect the A/F sensor connector.

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

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



NG
REPLACE AIR FUEL RATIO SENSOR
OK


2.INSPECT RELAY (Marking: A/F)
B060778E30

  1. Remove the A/F sensor heater relay from the engine room relay block.

  1. Measure the resistance of the relay.

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



NG
REPLACE RELAY
OK


3.CHECK WIRE HARNESS (A/F SENSOR - ECM)
A112437E01

A112696E01

  1. Disconnect the A18 or A25 A/F sensor connector.

  1. Disconnect the E6 ECM connector.

  1. Measure the resistance of the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    A18-1 (HT) - E16-2 (HA1A)
    		Below 1 Ω
    A18-3 (AF+) - E16-22 (A1A+)
    		Below 1 Ω
    A18-4 (AF-) - E16-30 (A1A-)
    		Below 1 Ω
    A25-1 (HT) - E16-1 (HA2A)
    		Below 1 Ω
    A25-3 (AF+) - E16-23 (A2A+)
    		Below 1 Ω
    A25-4 (AF-) - E16-31 (A2A-)
    		Below 1 Ω
    A18-1 (HT) or E16-2 (HA1A) - Body ground
    		10 kΩ or higher
    A18-3 (AF+) or E16-22 (A1A+) - Body ground
    		10 kΩ or higher
    A18-4 (AF-) or E16-30 (A1A-) - Body ground
    		10 kΩ or higher
    A25-1 (HT) or E16-1 (HA2A) - Body ground
    		10 kΩ or higher
    A25-3 (AF+) or E16-23 (A2A+) - Body ground
    		10 kΩ or higher
    A25-4 (AF-) or E16-31 (A2A-) - Body ground
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK

REPLACE ECM