Lexus IS250 IS220d GSE20 ALE20 - PARK ASSIST / MONITORING
INSPECT NO. 2 ULTRASONIC SENSOR
CHECK WIRE HARNESS (CLEARANCE WARNING ECU - NO. 2 ULTRASONIC SENSOR)
DTC B2239 Rear Right Center Sensor Malfunction
DESCRIPTION
The No. 2 ultrasonic sensor (rear right center sensor) is installed on the rear bumper.
The clearance warning ECU detects obstacles based on signals received from the rear right center sensor. If the rear right center sensor's circuit has an open, short or other malfunction, it will not function normally.
DTC No. | DTC Detection Condition | Trouble Area |
B2239 | Malfunction of No. 2 ultrasonic sensor (Rear right center sensor) | No. 2 ultrasonic sensor Wire harness Clearance warning ECU |
WIRING DIAGRAM
INSPECTION PROCEDURE
1.INSPECT NO. 2 ULTRASONIC SENSOR |

Remove the ultrasonic sensor.
Measure the resistance of the sensor.
- Standard resistance:
Tester Connection Condition Specified Condition S (S4-2) - E (S4-1) Always 600 to 1,200 kΩ
- NOTICE:
- Set the tester to the 100 kΩ range before performing the measurement.
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OK | |
2.CHECK WIRE HARNESS (CLEARANCE WARNING ECU - NO. 2 ULTRASONIC SENSOR) |

Disconnect the Q37 ECU connector.
Disconnect the S4 sensor connector.
Measure the resistance of the wire harness side connectors.
- Standard resistance:
Tester Connection Condition Specified Condition S7 (Q37-1) - S (S4-2) Always Below 1 Ω E7 (Q37-14) - E (S4-1) Always Below 1 Ω S7 (Q37-1) - Body ground Always 10 kΩ or higher E7 (Q37-14) - Body ground Always 10 kΩ or higher
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OK | ||
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