DTC No.	DTC Detection Condition	Trouble Area
P2237 P2240	Open in the circuit between terminals AF+ and AF- of the air fuel ratio sensor while the engine is running (2 trip detection logic).	Open in air fuel ratio sensor (for Bank 1, 2 Sensor 1) circuit Air fuel ratio sensor (for Bank 1, 2 Sensor 1) ECM
P2238 P2241	Case 1: Condition (a) or (b) continues for 5.0 seconds or more (2 trip detection logic): (a) AF+ voltage is 0.5 V or less. (b) (AF+) - (AF-) is 0.1 V or less. Case 2: Air fuel ratio sensor admittance is below 0.0091 1/Ω (2 trip detection logic).	Open or short in air fuel ratio sensor (for Bank 1, 2 Sensor 1) circuit Air fuel ratio sensor (for Bank 1, 2 Sensor 1) ECM
P2239 P2242	AF+ voltage is higher than 4.5 V for 5.0 seconds or more (2 trip detection logic).	Open or short in air fuel ratio sensor (for Bank 1, 2 Sensor 1) circuit Air fuel ratio sensor (for Bank 1, 2 Sensor 1) ECM
P2252 P2255	AF- voltage is 0.5 V or less for 5.0 seconds or more (2 trip detection logic).	Open or short in air fuel ratio sensor (for Bank 1, 2 Sensor 1) circuit Air fuel ratio sensor (for Bank 1, 2 Sensor 1) ECM
P2253 P2256	AF- voltage is higher than 4.5 V for 5.0 seconds or more (2 trip detection logic).	Open or short in air fuel ratio sensor (for Bank 1, 2 Sensor 1) circuit Air fuel ratio sensor (for Bank 1, 2 Sensor 1) ECM

HINT:

DTCs P2237, P2238, P2239, P2252 and P2253 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.

DTCs P2240, P2241, P2242, P2255 and P2256 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.

MONITOR DESCRIPTION

These DTCs are output when there is an open or short in the air fuel ratio sensor circuit, or if air fuel ratio sensor output drops.

To detect these problems, the voltage of the air fuel ratio sensor is monitored when turning the engine 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 0.6 V and 4.5 V, it is considered normal. If the voltage is outside of the specified range, or the admittance is below the standard value, the ECM will determine that there is a malfunction in the air fuel ratio sensor. If the same malfunction is detected in the next driving cycle, the MIL is illuminated and a DTC is stored.

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

CONFIRMATION DRIVING PATTERN

Start the engine and wait for 5 minutes or more.

WIRING DIAGRAM

Refer to DTC P2195 ().

INSPECTION PROCEDURE

HINT:

Refer to "Data List / Active Test" [AFS Voltage B1S1 and AFS Voltage B2S1] ().

Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. 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.

Bank 1 refers to the bank that includes the No. 1 cylinder*.
*: The No. 1 cylinder is the cylinder which is farthest from the transmission.

Bank 2 refers to the bank that does not include the No. 1 cylinder.

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:

for RHD
Tester Connection	Condition	Specified Condition
C22-1 (HA1A) - C46-22 (HA1A)	Always	Below 1 Ω
C22-3 (A1A+) - C46-126 (A1A+)	Always	Below 1 Ω
C22-4 (A1A-) - C46-125 (A1A-)	Always	Below 1 Ω
C23-1 (HA2A) - C46-20 (HA2A)	Always	Below 1 Ω
C23-3 (A2A+) - C46-103 (A2A+)	Always	Below 1 Ω
C23-4 (A2A-) - C46-102 (A2A-)	Always	Below 1 Ω
C22-1 (HA1A) or C46-22 (HA1A) - Body ground	Always	10 kΩ or higher
C22-3 (A1A+) or C46-126 (A1A+) - Body ground	Always	10 kΩ or higher
C22-4 (A1A-) or C46-125 (A1A-) - Body ground	Always	10 kΩ or higher
C23-1 (HA2A) or C46-20 (HA2A) - Body ground	Always	10 kΩ or higher
C23-3 (A2A+) or C46-103 (A2A+) - Body ground	Always	10 kΩ or higher
C23-4 (A2A-) or C46-102 (A2A-) - Body ground	Always	10 kΩ or higher

for LHD
Tester Connection	Condition	Specified Condition
C22-1 (HA1A) - C45-22 (HA1A)	Always	Below 1 Ω
C22-3 (A1A+) - C45-126 (A1A+)	Always	Below 1 Ω
C22-4 (A1A-) - C45-125 (A1A-)	Always	Below 1 Ω
C23-1 (HA2A) - C45-20 (HA2A)	Always	Below 1 Ω
C23-3 (A2A+) - C45-103 (A2A+)	Always	Below 1 Ω
C23-4 (A2A-) - C45-102 (A2A-)	Always	Below 1 Ω
C22-1 (HA1A) or C45-22 (HA1A) - Body ground	Always	10 kΩ or higher
C22-3 (A1A+) or C45-126 (A1A+) - Body ground	Always	10 kΩ or higher
C22-4 (A1A-) or C45-125 (A1A-) - Body ground	Always	10 kΩ or higher
C23-1 (HA2A) or C45-20 (HA2A) - Body ground	Always	10 kΩ or higher
C23-3 (A2A+) or C45-103 (A2A+) - Body ground	Always	10 kΩ or higher
C23-4 (A2A-) or C45-102 (A2A-) - 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 ().

NEXT

3.CHECK WHETHER DTC OUTPUT RECURS

Connect the GTS to the DLC3.

Turn the engine switch on (IG).

Turn the GTS on.

Clear DTCs ().

Start the engine.

Allow the engine to idle for 5 minutes or more.

Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

Read the pending DTCs.

Result
Result	Proceed to
No DTC is output	A
P2237, P2238, P2239, P2240, P2241, P2242, P2252, P2253, P2255 or P2256 is output	B

REPLACE ECM ()

END

1UR-FE ENGINE CONTROL

Land Cruiser URJ200 URJ202 GRJ200 VDJ200

SFI SYSTEM