P1150

DTC P1150 A/F Sensor Circuit Range Problem-Calif

CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of the exhaust gas, a three-way catalytic converter is used, but for the most efficient use of the three-way catalytic converter, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio.
The A/F sensor has the characteristic that provides output voltage* approximately proportional to the existing air-fuel ratio. The A/F sensor output voltage* is used to provide feedback for the ECM to control the air-fuel ratio.
By the A/F sensor output, the ECM can determine the deviation amount from the stoichiometric air-fuel ratio and control the proper injection time immediately. If the A/F sensor is malfunctioning, ECM is unable to perform accurate air-fuel ratio control.
The A/F sensor is equipped with a heater which heats the zirconia element. The heater is controlled by the ECM. When the intake air volume is low (the temp. of the exhaust gas is low), current flows to the heater to heat the sensor for accurate oxygen concentration detection.
*: The voltage value changes at the inside of the ECM only.





DETECTING CONDITION

HINT:
- After confirming DTC P1130, use the OBD II scan tool of LEXUS hand-held tester to confirm voltage output of A/F sensor from "CURRENT DATA".
- The A/F sensor's output voltage and the short-term fuel trim value can be read using the OBD II scan tool or LEXUS hand-held tester.
- The ECM controls the voltage of AFR+, AFL+, AFR- and AFL- terminals of ECM to the fixed voltage. Therefore, it is impossible to confirm the A/F sensor output voltage without OBD II scan tool or LEXUS hand-held tester
- OBD II scan tool (excluding LEXUS hand-held tester) displays the one fifth of the A/F sensor output voltage which is displayed on the LEXUS hand-held tester.





WIRING DIAGRAM





CONFIRMATION DRIVING PATTERN
(a) Connect the LEXUS hand-held tester to the DLC3.
(b) Switch the LEXUS hand-held tester from normal mode to check mode.
(c) Start the engine and warm it up with all accessory switches OFF.
(d) Drive the vehicle at 60 - 120 km/h (38 - 75 mph) and engine speed at 1,400 - 3,200 rpm for 3 - 5 min.

HINT: If a malfunction exists, the MIL will light up during steps (c) to (d).

NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction will not be possible. If you do not have a LEXUS hand-held tester, turn the ignition switch OFF after performing steps (c) and (d), then perform steps (c) and (d) again.

Step 1:

Step 2:

Step 3:

Step 4:

Step 5:

Step 6:

INSPECTION PROCEDURE

HINT:
- If DTC P1130 is displayed, check Bank 1 Sensor 1 circuit.
- If DTC P1150 is displayed, check Bank 2 Sensor 1 circuit.
- Read freeze frame data using LEXUS hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected, when troubleshooting it is useful for determining whether the vehicle was running or stopped, the engine warmed up or not, the air-fuel ratio lean or rich, etc. at the time of the malfunction.