P2238
2AZ-FXE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2237-P2239,P2252,P2253: Oxygen (A/F) Sensor Pumping Current Circuit / Open (Bank 1 Sensor 1)
CAUTION / NOTICE / HINT
DESCRIPTION
Refer to DTC P2195 P2195.
MONITOR DESCRIPTION
The Air-Fuel Ratio (A/F) sensor varies its output voltage in proportion to the air-fuel ratio. If the A/F sensor impedance (alternating current resistance) or output voltage deviates greatly from the standard range, the ECM (included in the hybrid vehicle control ECU) determines that there is an open or short in the A/F sensor circuit.
MONITOR STRATEGY
TYPICAL ENABLING CONDITIONS
P2237 (Open circuit between A1A+ and A1A-):
P2237 (Open circuit between A1A+ and A1A-)::
P2238 (Open circuit between A1A+ and GND
P2238 (Open circuit between A1A+ and GND:
Other:
Other::
TYPICAL MALFUNCTION THRESHOLDS
P2237 (Open circuit between A1A+ and A1A-):
P2237 (Open circuit between A1A+ and A1A-)::
P2238 (A/F sensor low admittance):
P2238 (A/F sensor low admittance)::
P2238 (Short circuit between A1A+ and GND):
P2238 (Short circuit between A1A+ and GND)::
P2238 (Short circuit between A1A+ and A1A-):
P2238 (Short circuit between A1A+ and A1A-)::
P2239 (Short circuit between A1A+ and +B):
P2239 (Short circuit between A1A+ and +B)::
P2252 (Short circuit between A1A- and GND):
P2252 (Short circuit between A1A- and GND)::
P2253 (Short circuit between A1A- and +B):
P2253 (Short circuit between A1A- and +B)::
WIRING DIAGRAM
INSPECTION PROCEDURE
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.
HINT
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 Techstream.
* (a) Connect the Techstream to the DLC3.
* (b) Put the engine in inspection mode Inspection Mode Procedure.
* (c) Turn the tester on.
* (d) Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
* (e) On the tester, select the following menu items: Powertrain / Engine / Active Test / Control the Injection Volume for A/F sensor.
* (f) 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).
* (g) Monitor the output voltages of the A/F and HO2 sensors (AFS 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:
NOTICE:
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, select the following menu items on the tester: Powertrain / Engine / Active Test / Control the Injection Volume for A/F Sensor / A/F Control System / AFS B1 S1 and O2S B1 S2 then press the graph button on the Data List view.
HINT
Read freeze frame data using the Techstream. The ECM (included in the hybrid vehicle control ECU) 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. INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE) P0031
NG -- REPLACE AIR FUEL RATIO SENSOR Removal
OK -- Continue to next step.
2. INSPECT INTEGRATION NO.1 RELAY (EFI RELAY) P0031
NG -- REPLACE INTEGRATION NO.1 RELAY (EFI MAIN RELAY)
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (A/F SENSOR - HYBRID VEHICLE CONTROL ECU) P2195
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. REPLACE AIR FUEL RATIO SENSOR
(a) Replace the air fuel ratio sensor Removal.
NEXT -- Continue to next step.
5. CHECK WHETHER DTC OUTPUT RECURS
(a) Connect the Techstream to the DLC3.
(b) Turn the power switch on (IG) and turn the tester on.
(c) Clear the DTCs DTC Check / Clear.
(d) Put the engine in inspection mode Inspection Mode Procedure.
(e) Allow the engine to idle for 5 minutes or more.
(f) Select the following menu items: Powertrain / Engine / Trouble Code / Pending.
(g) Read the pending DTCs.
Result:
B -- REPLACE HYBRID VEHICLE CONTROL ECU Removal
A -- END