2Az-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 (Link).

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 (sensor 1) circuit Air fuel ratio sensor (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 0.0015 1/Ω (2 trip detection logic).	Open or short in air fuel ratio sensor (sensor 1) circuit Air fuel ratio sensor (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 (sensor 1) circuit Air fuel ratio sensor (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 (sensor 1) circuit Air fuel ratio sensor (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 (sensor 1) circuit Air fuel ratio sensor (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	10 seconds: P2237 (Open circuit) and P2238 (Low Impedance) 5 seconds: Other
MIL Operation	2 driving cycles
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

P2237 and P2238
Monitor runs whenever following DTCs are not present	P0016 (VVT System - Misalignment) P0031, P0032 (Air Fuel Ratio Sensor Heater - Sensor 1) P0102, P0103 (Mass Air Flow Meter) 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 Engine Coolant Temperature for Closed Loop Fuel Control) P0128 (Thermostat) P0171, P0172 (Fuel System) P0301, P0302, P0303, P0304 (Misfire) P0335 (Crankshaft Position Sensor) P0340 (Camshaft Position Sensor) P0451, P0452, P0453 (EVAP System) P0500 (Vehicle Speed Sensor) P0505 (IAC Valve)

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 more

P2238 (Air Fuel Ratio Sensor Low Impedance)
Estimated sensor temperature	700 to 800°C (1292 to 1472°F)
Engine coolant temperature	10°C (50°F) or higher
Fuel cut	No executed

Other
Battery voltage	11 V or more
Ignition switch	ON
Time after ignition switch is 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 0.015 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	More 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	More 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 more
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 the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
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 the 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 (COROLLA_ZRE142 RM000000PDK0ZBX.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 P2195 (COROLLA_ZRE142 RM000000WC40PDX_07.html).

INSPECTION PROCEDURE

NOTICE:

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

HINT:

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 be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
Sensor 1 refers to the sensor closest to the engine assembly.
Sensor 2 refers to the sensor farthest away from the engine assembly.

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 (Check for Open):

Tester Connection
Condition
Specified Condition
B92-1 (HA1A) - B31-109 (HA1A)
Always
Below 1 Ω
B92-3 (A1A+) - B31-112 (A1A+)
B92-4 (A1A-) - B31-113 (A1A-)

Standard Resistance (Check for Short):

Tester Connection
Condition
Specified Condition
B92-1 (HA1A) or B31-109 (HA1A) - Body ground
Always
10 kΩ or higher
B92-3 (A1A+) or B31-112 (A1A+) - Body ground
B92-4 (A1A-) or B31-113 (A1A-) - Body ground

Reconnect the air fuel ratio sensor connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ECM)

OK

2.REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor (COROLLA_ZRE142 RM0000033D700IX.html).

NEXT

3.CHECK WHETHER DTC OUTPUT RECURS

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Clear the DTCs (COROLLA_ZRE142 RM000000PDK0ZBX.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
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 (COROLLA_ZRE142 RM000002WT402ZX.html)

END

Tester Connection	Condition	Specified Condition
B92-1 (HA1A) - B31-109 (HA1A)	Always	Below 1 Ω
B92-3 (A1A+) - B31-112 (A1A+)
B92-4 (A1A-) - B31-113 (A1A-)