Lexus NX: Oxygen (A/F) Sensor Pumping Current Circuit / Open (for A/F sensor) (Bank 1 Sensor 1) (P2237-P2239,P2252,P2253)

Lexus NX Service Manual / Engine & Hybrid System / 2ar-fxe (engine Control) / Sfi System / Oxygen (A/F) Sensor Pumping Current Circuit / Open (for A/F sensor) (Bank 1 Sensor 1) (P2237-P2239,P2252,P2253)

DESCRIPTION

Refer to DTC P2195.

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DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P2237	Oxygen (A/F) Sensor Pumping Current Circuit / Open (for A/F sensor) (Bank 1 Sensor 1)	An open in the circuit between terminals A1A+ and A1A- of the air fuel ratio sensor while the engine is running (2 trip detection logic).	Open in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P2238	Oxygen Sensor Pumping Current Circuit Low (for A/F sensor) (Bank 1 Sensor 1)	Case 1: Condition (a) or (b) is met for 5.0 seconds or more (2 trip detection logic): (a) Voltage at terminal A1A+ is 0.5 V or less (b) Voltage difference between terminals A1A+ and A1A- is 0.1 V or less Case 2: Air fuel ratio sensor admittance is less than 0.0054 1/Ω (2 trip detection logic).	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P2239	Oxygen Sensor Pumping Current Circuit High (for A/F sensor) (Bank 1 Sensor 1)	Condition (a) or (b) is met for 5.0 seconds or more (2 trip detection logic): (a) The A1A+ voltage is higher than 4.5 V (b) Voltage difference between terminals A1A+ and A1A- is higher than 0.8 V	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P2252	Oxygen Sensor Reference Ground Circuit Low (for A/F sensor) (Bank 1 Sensor 1)	The A1A- voltage is 0.5 V or less (2 trip detection logic).	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored
P2253	Oxygen Sensor Reference Ground Circuit High (for A/F sensor) (Bank 1 Sensor 1)	The A1A- voltage is higher than 4.5 V (2 trip detection logic).	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (sensor 1) ECM	Comes on	DTC stored

MONITOR DESCRIPTION

These DTCs are output when there is an open or short in the air fuel ratio sensor circuit, or if the air fuel ratio sensor output drops. To detect these problems, the voltage of the air fuel ratio sensor is monitored when turning the power switch on (IG), and the admittance (admittance is an electrical term that indicates the ease of flow of current) is checked while driving. If the voltage of the air fuel ratio sensor is between 0.5 V and 4.5 V, it is considered normal. If the voltage is out of the specified range, or the admittance is less than the standard value, the ECM determines that there is a malfunction in the air fuel ratio sensor. If the same malfunction is detected in the next driving cycle, the ECM will illuminate the MIL and store a DTC.

MONITOR STRATEGY

Related DTCs	P2237: Air fuel ratio sensor open circuit between A1A+ and A1A- P2238: Air fuel ratio sensor short circuit between A1A+ and A1A- P2238: Air fuel ratio sensor short circuit between A1A+ and GND P2238: Air fuel ratio sensor low admittance P2239: Air fuel ratio sensor short circuit between A1A+ and +B P2239: Air fuel ratio sensor short circuit between A1A+ and A1A- P2252: Air fuel ratio sensor short circuit between A1A- and GND P2253: Air fuel ratio sensor short circuit between A1A- and +B
Required Sensors/Components (Main)	Air fuel ratio sensor
Required Sensors/Components (Related)	Engine coolant temperature sensor Crankshaft position sensor
Frequency of Operation	Continuous
Duration	10 seconds: P2237 (open circuit) and P2238 (low admittance) 5 seconds: Others
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

P2237 and P2238

Monitor runs whenever the following DTCs are not stored

P0016 (VVT system - misalignment)

P0031, P0032, P101D (Air fuel ratio sensor heater)

P0102, P0103 (Mass air flow meter)

P0107, P0108 (Manifold absolute pressure)

P0112, P0113 (Intake air temperature sensor)

P0115, P0117, P0118 (Engine coolant temperature sensor)

P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle position sensor)

P0125 (Insufficient coolant temperature for closed loop fuel control)

P0128 (Thermostat)

P0171, P0172 (Fuel system)

P0300, P0301, P0302, P0303, P0304 (Misfire)

P0335 (Crankshaft position sensor)

P0340 (Camshaft position sensor)

P0401 (EGR system)

P0451, P0452, P0453 (EVAP system)

P0505 (Idle speed control)

P219A, P219C, P219D, P219E, P219F (Air-fuel ratio imbalance)

P2239, P2252 and P2253

Monitor runs whenever the following DTCs are not stored

None

P2237: Air Fuel Ratio Sensor Open Circuit Between A1A+ and A1A-

Estimated sensor temperature	450 to 550°C (842 to 1022°F)
Engine	Running
Auxiliary battery voltage	11 V or higher
Power switch	On (IG)
Time after power switch is off to on (IG)	5 seconds or more

P2238: Low Admittance

Estimated sensor temperature	700 to 800°C (1292 to 1472°F)
Engine coolant temperature	5°C (41°F) or higher (varies with engine coolant temperature at engine start)
Fuel cut	Not executed

Others

Auxiliary battery voltage	11 V or higher
Power switch	On (IG)
Time after power switch is off to on (IG)	5 seconds or more

TYPICAL MALFUNCTION THRESHOLDS

P2237: Open Circuit Between A1A+ and A1A-

Air fuel ratio sensor admittance

Less than 0.0018 1/Ω

P2238: Low Admittance

Air fuel ratio sensor admittance

Less than 0.0054 1/Ω

P2238: Short Circuit Between A1A+ and GND

A1A+ terminal voltage

0.5 V or less

P2238: Short Circuit Between A1A+ and A1A-

Difference between A1A+ and A1A- terminal voltage

0.1 V or less

P2239: Short Circuit Between A1A+ and +B

A1A+ terminal voltage

Higher than 4.5 V

P2239: Short Circuit Between A1A+ and A1A-

Difference between A1A+ and A1A- terminal voltage

Higher than 0.8 V

P2252: Short Circuit Between A1A- and GND

A1A- terminal voltage

0.5 V or less

P2253: Short Circuit Between A1A- and +B

A1A- terminal voltage

Higher than 4.5 V

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG) and turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off and wait for at least 30 seconds.
Turn the power switch on (IG) and turn the Techstream on.
Put the engine in inspection mode (maintenance mode).
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Start the engine and wait 5 minutes.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read the pending DTCs.
HINT:
- If a pending DTC is output, the system is malfunctioning.
- If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P2237, P2238, P2239, P2252 or P2253.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or N/A, idle the engine for 5 minutes and check the DTC judgment result again.

If no pending DTC is output, perform a universal trip and check for permanent DTCs.
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HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P2195.

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CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following procedure.

HINT:

Refer to "Data List / Active Test" [AFS Voltage B1S1].
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Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.
Read freeze frame data using the Techstream. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

(a) Disconnect the air fuel ratio sensor connector.

(b) Disconnect the ECM connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
C5-1 (HA1A) - C48-23 (HA1A)	Always	Below 1 Ω
C5-3 (A1A+) - C48-133 (A1A+)	Always	Below 1 Ω
C5-4 (A1A-) - C48-134 (A1A-)	Always	Below 1 Ω
C5-1 (HA1A) or C48-23 (HA1A) - Body ground	Always	10 kΩ or higher
C5-3 (A1A+) or C48-133 (A1A+) - Body ground	Always	10 kΩ or higher
C5-4 (A1A-) or C48-134 (A1A-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor.

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HINT:

Perform "Inspection After Repair" after replacing the air fuel ratio sensor.

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3.	CHECK WHETHER DTC OUTPUT RECURS

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(d) Clear the DTCs.

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Powertrain > Engine and ECT > Clear DTCs

(e) Turn the power switch off and wait for at least 30 seconds.

(f) Turn the power switch on (IG) and turn the Techstream on.

(g) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

(h) Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

Powertrain > Engine and ECT > Utility

Tester Display
All Readiness

(i) Input the DTC: P2237, P2238, P2239, P2252 or P2253.

(j) Check the DTC judgment result.

Result	Proceed to
NORMAL (DTCs are not output)	A
ABNORMAL (DTC P2237, P2238, P2239, P2252 or P2253 is output)	B

Result

Proceed to

NORMAL

(DTCs are not output)

ABNORMAL

(DTC P2237, P2238, P2239, P2252 or P2253 is output)

END

REPLACE ECM

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Lexus NX: Oxygen (A/F) Sensor Pumping Current Circuit / Open (for A/F sensor) (Bank 1 Sensor 1) (P2237-P2239,P2252,P2253)

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