B1787 Lexus Code - Rear Occupant Classification Sensor Left Collision Detection
Quick Answer
The Diagnostic Trouble Code (DTC) B1787 is output when the Occupant Detection ECU receives a collision detection signal sent by the Rear Occupant Classification Sensor Left (LH) when an accident occurs. Common causes include Faulty Separate Type Rear Seat Cushion Spring Assembly Left (Rear Occupant Classification Sensor Left), Separate Type Rear Seat Cushion Spring Assembly Left harness is open or shorted, Separate Type Rear Seat Cushion Spring Assembly Left circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- B1787 Lexus indicates Rear Occupant Classification Sensor Left Collision Detection.
- Common causes
- Common causes include Faulty Separate Type Rear Seat Cushion Spring Assembly Left (Rear Occupant Classification Sensor Left), Separate Type Rear Seat Cushion Spring Assembly Left harness is open or shorted, Separate Type Rear Seat Cushion Spring Assembly Left circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code B1787 Lexus Description
What are the Possible Causes of the DTC B1787 Lexus?
- Faulty Separate Type Rear Seat Cushion Spring Assembly Left (Rear Occupant Classification Sensor Left)
- Separate Type Rear Seat Cushion Spring Assembly Left harness is open or shorted
- Separate Type Rear Seat Cushion Spring Assembly Left circuit poor electrical connection
- Faulty Occupant Detection ECU
How to Fix the DTC B1787 Lexus?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B1787 Lexus code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service
- Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
- Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
- Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
- Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.
Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.
Frequently Asked Questions about B1787 Lexus Code
1. What are the common symptoms of OBDII code B1787 in a Lexus related to the Rear Occupant Classification Sensor Left Collision Detection?
The common symptoms include the airbag warning light illuminating on the dashboard and a potential failure of the rear occupant classification system.
2. What are the possible causes of OBDII code B1787 in a Lexus indicating an issue with the Rear Occupant Classification Sensor Left Collision Detection?
Possible causes may include a malfunction in the rear occupant classification sensor, wiring issues, or a faulty airbag control module.
3. How can I diagnose the OBDII code B1787 in a Lexus linked to the Rear Occupant Classification Sensor Left Collision Detection?
Diagnosis typically involves using an OBDII scanner to retrieve the specific trouble code, inspecting the rear occupant classification sensor and related wiring, and conducting a thorough system test.
4. Is it safe to drive my Lexus with OBDII code B1787 indicating a problem with the Rear Occupant Classification Sensor Left Collision Detection?
It is recommended to address the issue promptly to ensure the proper functioning of the rear occupant classification system and the airbag system. Continuing to drive with this issue may compromise occupant safety in the event of a collision.
5. How can I reset OBDII code B1787 in my Lexus after repairing the Rear Occupant Classification Sensor Left Collision Detection issue?
After repairing the underlying problem, you can typically clear the trouble code using an OBDII scanner or by disconnecting the car battery for a few minutes to reset the system.
6. Can I repair OBDII code B1787 related to the Rear Occupant Classification Sensor Left Collision Detection in my Lexus myself?
While some DIY enthusiasts may be able to address simple wiring issues, it is recommended to consult a professional mechanic or authorized Lexus service center for accurate diagnosis and repair of the rear occupant classification sensor system.
7. How much does it typically cost to repair OBDII code B1787 indicating a problem with the Rear Occupant Classification Sensor Left Collision Detection in a Lexus?
The cost of repair can vary depending on the specific issue, parts needed, and labor rates. It is advisable to obtain quotes from reputable repair shops or dealerships for an accurate estimate.
8. Are there any recalls or technical service bulletins related to OBDII code B1787 and the Rear Occupant Classification Sensor Left Collision Detection in Lexus vehicles?
It is advisable to check with Lexus authorized service centers or visit the National Highway Traffic Safety Administration (NHTSA) website for any relevant recalls or technical service bulletins related to this issue.
9. What steps can I take to prevent OBDII code B1787 in my Lexus due to Rear Occupant Classification Sensor Left Collision Detection from occurring again?
Regular maintenance, avoiding physical damage to the sensor system, and addressing any warning lights or unusual symptoms promptly can help prevent the recurrence of this issue.
10. How critical is it to address OBDII code B1787 related to the Rear Occupant Classification Sensor Left Collision Detection in my Lexus?
Addressing this code is crucial as it directly impacts the proper functioning of the rear occupant classification system and the overall safety of the vehicle's occupants in the event of a collision.
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