P2252

2GR-FSE ENGINE CONTROL: SFI SYSTEM: P2237-P2239,P2240-P2242,P2252,P2253,P2255,P2256: Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)

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 and 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.

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 does not include cylinder No. 1.

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 voltage output 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 and P2240 (Air fuel ratio sensor open circuit between A1A+ and A1A-/A2A+ and A2A-)

P2238 and P2241 (Low admittance)

Others

TYPICAL MALFUNCTION THRESHOLDS

P2237 and P2240 (Open circuit between A1A+ and A1A-/A2A+ and A2A-)

P2238 and P2241 (Low admittance)

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

CONFIRMATION DRIVING PATTERN

1. Connect the Techstream to the DLC3.

2. Turn the engine switch on (IG) and turn the Techstream on.

3. Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure) Reading and Clearing Diagnostic Trouble Codes.

4. Turn the engine switch off and wait for 30 seconds.

5. Turn the engine switch on (IG) and turn the Techstream on [A].

6. Start the engine and wait 5 minutes.

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

8. Read the pending DTC [B].

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 / 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 NORMAL, the system is normal.
- If the judgment result shows INCOMPLETE or UNKNOWN, idle the engine for 5 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
Malfunctioning areas can be identified by performing the Control the Injection Volume for A/F Sensor 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.

1. Connect the Techstream to the DLC3.

2. Start the engine.

3. Turn the Techstream on.

4. Warm up the engine at 2500 rpm for approximately 90 seconds.

5. Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor.

6. Perform Active Test operation with the engine idling (press the RIGHT or LEFT button to change the fuel injection volume).

7. 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%.
- Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

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.

- Performing Control the Injection Volume for A/F Sensor 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 / Active Test / Control the Injection Volume for A/F Sensor / AFS Voltage B1S1 and O2S B2S1 or AFS Voltage B1S2 and O2S B2S2.

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 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 (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 (Check for Open):

Standard Resistance (Check for Short):

(d) Reconnect the ECM connector.

(e) Reconnect the air fuel ratio sensor connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR FUEL RATIO SENSOR - ECM)
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. CHECK WHETHER DTC OUTPUT RECURS

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(e) Start the engine.

(f) Allow the engine to idle for 5 minutes or more.

(g) Enter the following menus: Powertrain / Engine / Trouble Codes / Pending.

(h) Read the pending DTCs.

Result:

B -- REPLACE ECM Removal

A -- END