P2239
4GR-FSE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2237: Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)
DTC P2237 - Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)
DTC P2238 - Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)
DTC P2239 - Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 1 Sensor 1)
DTC P2240 - Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 2 Sensor 1)
DTC P2241 - Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 2 Sensor 1)
DTC P2242 - Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 2 Sensor 1)
DTC P2252 - Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 1 Sensor 1)
DTC P2253 - Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 1 Sensor 1)
DTC P2255 - Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 2 Sensor 1)
DTC P2256 - Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 2 Sensor 1)
CAUTION / NOTICE / HINT
DESCRIPTION
HINT:
- Although the DTC titles say 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.
These DTCs are set when there is an open or short in the A/F sensor circuit, or if A/F sensor output drops. To detect these problems, the voltage of the A/F sensor is monitored when turn 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 A/F sensor is between 0.6V and 4.5V, it is considered normal. If the voltage is out of the specified range, or the admittance is less than the standard value, the ECM will determine that there is a malfunction in the A/F sensor. If the same malfunction is detected in next driving cycle, the MIL will be illuminated and a DTC will be stored.
The A/F sensor, which is located between the exhaust manifold and catalyst, consists of alloyed metal elements and a heater.
Depending on the engine operating conditions, the heater heats the sensor elements to activate them. Battery voltage is applied to the heater, the sensor ground is controlled by the ECM using a duty ratio.
The sensor elements convert the oxygen concentration in the exhaust gas into voltage values to output. Based on the voltage, the ECM determines the air-fuel ratio and regulates the fuel injection volume depending on the air-fuel ratio and engine operating conditions. The voltage changes between 0.6V and 4.5V while the engine is running. If the air-fuel ratio is lean, which means the oxygen concentration in the exhaust gas is high, the voltage is high. If the air-fuel ratio is rich, which means the oxygen concentration in the exhaust gas is low, the voltage is low.
MONITOR DESCRIPTION
These DTCs are output when there is an open or short in the A/F sensor circuit, or if A/F sensor output drops. To detect these problems, the voltage of the A/F sensor is monitored when turn 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 A/F sensor is between 0.6V and 4.5V, it is considered normal. If the voltage is out of the specified range, or the admittance is less than the standard value, the ECM will determine that there is a malfunction in the A/F sensor. If the same malfunction is detected in next driving cycle, the MIL will be illuminated and a DTC will be stored.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
All:
A/F sensor open circuit between A1A+ and A1A-/A2A+ and A2A-:
A/F sensor low impedance:
Other:
TYPICAL MALFUNCTION THRESHOLDS
P2237 and P2240 (Open circuit between A1A+ and A1A-/A2A+ and A2A-:
P2238 and P2241 (Low impedance):
P2238 and P2241 (Short circuit between A1A+ and GND/A2A+ and GND):
P2238 and P2241 (Short circuit between A1A+ and A1A-/A2A+ and A2A-:
P2239 and P2242 (Short circuit between A1A+ and +B/A2A+ and +B):
P2252 and P2255 (Short circuit between A1A- and GND/A2A- and GND):
P2253 and P2256 (Short circuit between A1A- and +B/A2A- and +B):
COMPONENT OPERATING RANGE
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
Techstream 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 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 Techstream.
1 Connect Techstream to the DLC3.
2 Start the engine and turn the tester ON.
3 Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.
4 On the tester, enter the following menu: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.
5 Perform the Control the Injection Volume for A/F Sensor operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).
6 Monitor the output voltages of the A/F and HO2 sensors (AFS Voltage B1 S1 and O2S B1 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%.
- The sensors react in accordance with increases and decreases in the fuel injection volume.
Standard:
NOTE:
The A/F sensor has an output delay of a few seconds and the HO2 sensor has a maximum output delay of approximately 20 seconds.
- Following the Control the Injection Volume for A/F Sensor procedure enables technicians to check and graph the output voltages of both the A/F and HO2 sensors.
- To display the graph, enter the following menus on the tester: Control the Injection Volume for A/F Sensor / A/F Control System / AFS Voltage B1 S1 or AFS Voltage B2 S1 and O2S B1 S2 or O2S B2 S2. Then press the graph button on the Data List view.
HINT:
Read freeze frame data using 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 (A/F SENSOR - ECM) P2195
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. REPLACE AIR FUEL RATIO SENSOR
Replace A/F sensor Removal.
NEXT -- Continue to next step.
3. CHECK WHETHER DTC OUTPUT RECURS
(a) Connect Techstream to the DLC3.
(b) Turn the engine switch On (IG) and turn the tester ON.
(c) Clear the DTCs DTC Check / Clear.
(d) Start the engine.
(e) Allow the engine to idle for 5 minutes or more.
(f) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.
(g) Read pending DTCs.
Result:
B -- REPLACE ECM
A -- END