P2237

1GR-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2237-P2239, P2240-P2242, P2252, P2253, P2255, P2256: Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)


DESCRIPTION

Refer to DTC P2195 P2195.





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.
* Bank 1 refers to the bank that includes cylinder No. 1.
* Bank 2 refers to the bank that includes cylinder No. 2.

MONITOR DESCRIPTION

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.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

P2237, P2238, P2240 and P2241





P2239, P2242, P2252, P2253, P2255 and P2256





P2237 and P2240 (Open Circuit between AF+ and AF-)





P2238 and P2241 (Low Impedance)





P2238 and P2241 (Short Circuit between AF+ and GND)





P2238 and P2241 (Short Circuit between AF+ and AF-)





P2239 and P2242 (Short Circuit between AF+ and +B)





P2239 and P2242 (Short Circuit between AF+ and VCC)





P2252 and P2255 (Short Circuit between AF- and GND)





P2253 and P2256 (Short Circuit between AF- and +B)





P2253 and P2256 (Short Circuit between AF- and VCC)





TYPICAL MALFUNCTION THRESHOLDS

P2237 and P2240 (Open Circuit between AF+ and AF-)





P2238 and P2241 (Low Impedance)





P2238 and P2241 (Short Circuit between AF+ and GND)





P2238 and P2241 (Short Circuit between AF+ and AF-)





P2239 and P2242 (Short Circuit between AF+ and +B)





P2239 and P2242 (Short Circuit between AF+ and VCC)





P2252 and P2255 (Short Circuit between AF- and GND)





P2253 and P2256 (Short Circuit between AF- and +B)





P2253 and P2256 (Short Circuit between AF- and VCC)





CONFIRMATION DRIVING PATTERN





1. Connect the Techstream to the DLC3.

2. Turn the ignition switch to ON and turn the Techstream on.

3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC operation).

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

5. Turn the ignition switch to ON and turn the Techstream on [A].

6. Start the engine and wait 2 minutes.

7. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [B].

8. Read the pending DTCs.

HINT
* If a pending DTC is output, the system is malfunctioning.
* If a pending DTC is not output, perform the following procedure.

9. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

10. Input the DTC: P2237, P2238, P2239, P2240, P2241, P2242, P2252, P2253, P2255 or P2256.

11. Check the DTC judgment result.





HINT
* If the judgment result shows ABNORMAL, the system has a malfunction.
* If the judgment result shows INCOMPLETE or UNKNOWN, idle the engine for 3 minutes and check the DTC judgment result again [C].

12. If no pending DTC is output, perform a universal trip and check for permanent DTCs Reading and Clearing Diagnostic Trouble Codes.

HINT
* If a permanent DTC is output, the system is malfunctioning.
* If no permanent DTC is output, the system is normal.

WIRING DIAGRAM

Refer to DTC P2195 P2195.

INSPECTION PROCEDURE

HINT
* Although the DTC titles say heated 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.

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 air fuel ratio sensor, heated oxygen 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 Techstream.

- (a) Connect the Techstream to the DLC3.

- (b) Start the engine and turn the Techstream on.

- (c) Warm up the engine at an engine speed of 2500 rpm for approximately 90 seconds.

- (d) Enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor.

- (e) 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).

- (f) Monitor the output voltages of the air fuel ratio and heated oxygen sensors (AFS Voltage B1S1 and O2S B1S2, or AFS Voltage B2S1 and O2S B2S2) displayed on the Techstream.

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:





NOTICE:
The air fuel ratio sensor has an output delay of a few seconds and the heated oxygen 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 air fuel ratio and heated oxygen sensors.

- To display the graph, enter the following menus: Powertrain / Engine and ECT / Active Test / Control the Injection Volume for A/F Sensor / AFS Voltage B1S1 or AFS Voltage B2S1, and O2S B1S2 or O2S B2S2. Then press the graph button on the Data List display.

HINT
* Read freeze frame data using the Techstream. 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.

PROCEDURE

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

(a) Disconnect the air fuel ratio sensor connector.

(b) Disconnect the ECM connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

2. REPLACE AIR FUEL RATIO SENSOR

(a) Replace the air fuel ratio sensor Removal.

NEXT -- Continue to next step.

3. PERFORM CONFIRMATION DRIVING PATTERN

(a) Drive the vehicle according to Confirmation Driving Pattern.

NEXT -- Continue to next step.

4. CHECK WHETHER DTC OUTPUT RECURS

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON and turn the Techstream on.

(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Code / Pending.

(d) Read the pending DTCs.

Result





B -- REPLACE ECM Removal

A -- END