1Nz-Fe Engine Control. Dtc P2237 Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)

Although the DTC titles say oxygen sensor, these DTCs relate to the air fuel ratio sensor.
Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.
Refer to DTC P2195 (YARIS_NCP93 RM000000WC40LQX_01.html).

DTC No.	DTC Detection Condition	Trouble Area
P2237	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 (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2238	Case 1 Condition (a) or (b) continues 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: Less than 0.0074 1/Ω (2 trip detection logic)	Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2239	The A1A+ voltage is higher than 4.5 V (2 trip detection logic).	Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2252	The A1A- voltage is 0.5 V or less (2 trip detection logic).	Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM
P2253	The A1A- voltage is higher than 4.5 V (2 trip detection logic).	Open or short in air fuel ratio sensor (bank 1 sensor 1) circuit Air fuel ratio sensor (bank 1 sensor 1) ECM

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 ignition switch to ON, 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 0.6 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 next driving cycle, the MIL is illuminated and a DTC is stored.

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 Impedance P2239: Air Fuel Ratio Sensor Short Circuit Between A1A+ and +B 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	P2237: 10 seconds P2238 (air fuel ratio sensor low admittance): 10 seconds Others: 5 seconds
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

P2237, P2238:
Monitor runs whenever following DTCs not present	P0016 (VVT System - Misalignment) P0031, P0032, P101D (Air Fuel Ratio Sensor Heater) P0102, P0103 (Mass Air Flow Sensor) P0112, P0113 (Intake Air Temperature Sensor) P0115, P0117, P0118 (Engine Coolant Temperature Sensor) P0125 (Insufficient Coolant Temperature for Closed Loop Fuel Control) P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (Throttle Position Sensor) P0128 (Thermostat) P0171, P0172 (Fuel System) P0301 - P0304 (Misfire) P0335 (Crankshaft Position Sensor) P0340 (Camshaft Position Sensor) P0451, P0452, P0453 (EVAP System) P0500 (Vehicle Speed Sensor) P0505 (IAC Valve) P219A (Air Fuel Ratio Imbalance)

P2239, P2252, P2253:
Monitor runs whenever following DTCs not present	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
Battery voltage	11 V or higher
Ignition switch	ON
Time after Ignition switch is OFF to ON	5 seconds or more

P2238 (Air Fuel Ratio Sensor Low Impedance):
Estimated sensor temperature	700 to 800°C (1292 to 1472°F)
Engine coolant temperature	0°C (32°F) or higher
Fuel cut	Not executed

P2238 (Air Fuel Ratio Sensor Short Circuit Between A1A+ and A1A-, GND):
Battery voltage	11 V or higher
Ignition switch	ON
Time after ignition switch is turned from off to ON	5 seconds or more

Other:
Battery voltage	11 V or higher
Ignition switch	ON
Time after ignition switch is turned from off to ON	5 seconds or more

TYPICAL MALFUNCTION THRESHOLDS

P2237 (Air Fuel Ratio Sensor Open Circuit Between A1A+ and A1A-):
Air fuel ratio sensor admittance	Below 0.002 1/Ω

P2238 (Air Fuel Ratio Sensor Low Impedance):
Air fuel ratio sensor admittance	Below 0.0074 1/Ω

P2238 (Air Fuel Ratio Sensor Short Circuit Between A1A+ and GND):
A1A+ terminal voltage	0.5 V or less

P2239 (Air Fuel Ratio Sensor Short Circuit Between A1A+ and +B):
A1A+ terminal voltage	Higher than 4.5 V

P2252 (Air Fuel Ratio Sensor Short Circuit Between A1A- and GND):
A1A- terminal voltage	0.5 V or less

P2253 (Air Fuel Ratio Sensor Short Circuit Between A1A- and +B):
A1A- terminal voltage	Higher than 4.5 V

P2238 (Air Fuel Ratio Sensor Short Circuit Between A1A+ and A1A-):
Difference between A1A+ terminal and A1A- terminal voltage	0.1 V or less

COMPONENT OPERATING RANGE

Air fuel ratio sensor admittance	0.002 1/Ω or higher
A1A+ terminal voltage	0.5 to 4.5 V
A1A- terminal voltage	0.5 to 4.5 V
Difference between A1A+ and A1A- terminal voltages	0.1 to 0.8 V

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the Techstream on.
Start the engine and wait 5 minutes.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
Read pending DTCs.
HINT:
1. If a pending DTC is output, the system is malfunctioning.
2. 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 (YARIS_NCP93 RM000000PDK0T5X.html).
HINT:
1. If a permanent DTC is output, the system is malfunctioning.
2. If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P0031 (YARIS_NCP93 RM000000WC10MFX_07.html).

INSPECTION PROCEDURE

NOTICE:

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

HINT:

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.
Refer to "Data List / Active Test" [AFS Voltage B1S1] (YARIS_NCP93 RM000000SXS05AX.html).

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

Disconnect the air fuel ratio sensor connector.

Disconnect the ECM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
C56-1 (HA1A) - C51-23 (HA1A)	Always	Below 1 Ω
C56-3 (A1A+) - C51-133 (A1A+)	Always	Below 1 Ω
C56-4 (A1A-) - C51-134 (A1A-)	Always	Below 1 Ω
C56-1 (HA1A) or C51-23 (HA1A) - Body ground	Always	10 kΩ or higher
C56-3 (A1A+) or C51-133 (A1A+) - Body ground	Always	10 kΩ or higher
C56-4 (A1A-) or C51-134 (A1A-) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

2.REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor (YARIS_NCP93 RM000003VIL00HX.html).
HINT:
Perform "Inspection After Repair" after replacing the air fuel ratio sensor (YARIS_NCP93 RM000004NJD006X.html).

NEXT

3.CHECK WHETHER DTC OUTPUT RECURS (DTC P2237, P2238, P2239, P2252 OR P2253)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Clear the DTCs (YARIS_NCP93 RM000000PDK0T5X.html).

Turn the ignition switch off and wait for at least 30 seconds.

Turn the ignition switch to ON.

Turn the Techstream on.

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

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

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

REPLACE ECM (YARIS_NCP93 RM000001CN002IX.html)

END