2Gr-Fe Engine Control System. Dtc P2238 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)

Although the DTC titles include oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

The A/F sensor generates voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.
The A/F sensor is the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows into the heater to heat the sensor, in order to facilitate accurate oxygen concentration detection. In addition, the sensor and heater portions are narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.
A three-way catalytic converter (TWC) is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) into less harmful substances. To allow the TWC to function effectively, it is necessary to keep the air-fuel ratio of the engine near the stoichiometric air-fuel ratio.
*: Value changes inside the ECM. Since the A/F sensor is the current output element, a current is converted to a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

Toyota Rav4. Aca30, 33, 38 Gsa33 Zsa30, 35.2Gr-Fe Engine Control System.Sfi System.
Dtc
P2238 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)

DTC No.	DTC Detection Condition	Trouble Area
P2238 P2241	Case 1: Condition (a) or (b) continues for 5.0 seconds or more (1 trip detection logic): (a) AF+ voltage is 0.5 V or less (b) (AF+) - (AF-) = 0.1 V or less Case 2: A/F sensor admittance: Less than 0.022 1/Ω (2 trip detection logic)	Open or short in A/F sensor (bank 1, 2 sensor 1) circuit A/F sensor (bank 1, 2 sensor 1) A/F sensor heater A/F relay A/F sensor heater circuits ECM
P2239 P2242	AF+ voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic)	Open or short in A/F sensor (bank 1, 2 sensor 1) circuit A/F sensor (bank 1, 2 sensor 1) A/F sensor heater A/F relay A/F sensor heater circuits 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 A/F sensor (bank 1, 2 sensor 1) circuit A/F sensor (bank 1, 2 sensor 1) A/F sensor heater A/F relay A/F sensor heater circuits ECM
P2253 P2256	AF- voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic)	Open or short in A/F sensor (bank 1, 2 sensor 1) circuit A/F sensor (bank 1, 2 sensor 1) A/F sensor heater A/F relay A/F sensor heater circuits ECM

HINT:

DTCs P2238, P2239, P2252 and P2253 indicate malfunctions related to the bank 1 A/F sensor circuit.
DTCs P2241, P2242, P2255 and P2256 indicate malfunctions related to the bank 2 A/F sensor circuit.
Bank 1 refers to the bank that includes cylinder No. 1.
Bank 2 refers to the bank that includes cylinder No. 2.

WIRING DIAGRAM

Refer to DTC P2195 (RAV4_ACA30 RM000000WC40NOX_07.html).

INSPECTION PROCEDURE

HINT:

Intelligent tester only:

Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor function provided in the Active Test. The Control the Injection Volume for A/F Sensor function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the Control the Injection Volume for A/F Sensor operation using the intelligent tester.

Connect the intelligent tester to the DLC3.
Start the engine and turn the tester on.
Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
On the tester, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
Perform the Control the Injection Volume for A/F Sensor operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
Monitor the output voltages of the A/F and HO2 sensors (AFS B1 S1 and O2S B1 S2 or AFS B2 S1 and O2S B2 S2) displayed on the tester.

HINT:

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 %.

Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Tester Display (Sensor)	Injection Volume	Status	Voltage
AFS B1S1 or AFS B2S1 (A/F)	+25 %	Rich	Less than 3.0 V
AFS B1S1 or AFS B2S1 (A/F)	-12.5 %	Lean	More than 3.35 V
O2S B1S2 or O2S B2S2 (HO2)	+25 %	Rich	More than 0.55 V
O2S B1S2 or O2S B2S2 (HO2)	-12.5 %	Lean	Less than 0.4 V

NOTICE:

The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.

Case	Air Fuel Ratio Sensor (Sensor 1) Output Voltage	Heated Oxygen Sensor (Sensor 2) Output Voltage	Main Suspected Trouble Area
1			-
2			Air fuel ratio sensor Air fuel ratio sensor heater Air fuel ratio sensor circuit
3			Heated oxygen sensor Heated oxygen sensor heater Heated oxygen sensor circuit
4			Fuel pressure Gas leakage from exhaust system (Air fuel ratio extremely lean or rich)

Performing "Control the Injection Volume for A/F Sensor" enables technicians to check and graph the output voltages of both the A/F and HO2 sensors.
The following A/F Control procedure enables the technician to check and graph the voltage output of both the heated oxygen sensors. To display the graph, select the following menu items on the tester: View/Line Graph.

HINT:

Read freeze frame data using the intelligent tester. 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 (RAV4_ACA30 RM000000PDS09FX.html).

1.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)

Disconnect the A/F sensor connector.

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

Standard resistance:
Bank 1:
Tester Connection
Condition
Specified Condition
HA1A (1) - +B (2)
20°C (68°F)
1.8 to 3.4 Ω
HA1A (1) - A1A- (4)
-
10 kΩ or higher
Bank 2:
Tester Connection
Condition
Specified Condition
HA2A (1) - +B (2)
20°C (68°F)
1.8 to 3.4 Ω
HA2A (1) - A2A- (4)
-
10 kΩ or higher

Reconnect the A/F sensor connector.

REPLACE AIR FUEL RATIO SENSOR (RAV4_ACA30 RM000001RO200SX.html)

OK

2.CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)

Disconnect the A/F sensor connector.

Disconnect the ECM connector.

Measure the resistance.

Standard resistance (Check for open):

Bank 1:

Tester Connection	Specified Condition
HA1A (B7-1) - HA1A (B96-86)	Below 1 Ω
A1A+ (B7-3) - A1A+ (B96-93)	Below 1 Ω
A1A- (B7-4) - A1A- (B96-116)	Below 1 Ω

Bank 2:

Tester Connection	Specified Condition
HA2A (B67-1) - HA2A (B96-109)	Below 1 Ω
A2A+ (B67-3) - A2A+ (B96-120)	Below 1 Ω
A2A- (B67-4) - A2A- (B96-119)	Below 1 Ω

Standard resistance (Check for short):

Bank 1:

Tester Connection	Specified Condition
HA1A (B7-1) or HA1A (B96-86) - Body ground	10 kΩ or higher
A1A+ (B7-3) or A1A+ (B96-93) - Body ground	10 kΩ or higher
A1A- (B7-4) or A1A- (B96-116) - Body ground	10 kΩ or higher

Bank 2:

Tester Connection	Specified Condition
HA2A (B67-1) or HA2A (B96-109) - Body ground	10 kΩ or higher
A2A+ (B67-3) or A2A+ (B96-120) - Body ground	10 kΩ or higher
A2A- (B67-4) or A2A- (B96-119) - Body ground	10 kΩ or higher

Reconnect the ECM connector.

Reconnect the A/F sensor connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

Read the DTCs using the intelligent tester.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Result:

Display (DTC Output)
Proceed to
P2A00 and/or P2A03
A
No output
B

REPLACE ECM (RAV4_ACA30 RM0000017UN01LX.html)

A

4.REPLACE AIR FUEL RATIO SENSOR

Replace the air fuel ratio sensor (RAV4_ACA30 RM000001RO200SX.html).

NEXT

5.PERFORM CONFIRMATION DRIVING PATTERN

NEXT

6.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

Read the DTCs using the intelligent tester.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Result:

Display (DTC Output)
Proceed to
No output
A
P2A00 and/or P2A03
B

REPLACE ECM (RAV4_ACA30 RM0000017UN01LX.html)

END

Tester Connection	Condition	Specified Condition
HA1A (1) - +B (2)	20°C (68°F)	1.8 to 3.4 Ω
HA1A (1) - A1A- (4)	-	10 kΩ or higher

Display (DTC Output)	Proceed to
P2A00 and/or P2A03	A
No output	B

Display (DTC Output)	Proceed to
No output	A
P2A00 and/or P2A03	B