Driver Seatbelt Pretensioner Circuit Low Resistance
The B1885 code indicates that the airbag control module (RCM or RCM/SOS) has detected a resistance below the allowable range in the driver's seatbelt pretensioner circuit. The pretensioner (squib) is a pyrotechnic device that tightens the seatbelt milliseconds before impact to secure the occupant. Technically, the module sends a small test current to measure circuit resistance. If the resistance is abnormally low, it typically points to an internal short in the pretensioner squib or a short to ground/voltage in the wiring connecting the pretensioner to the control module. When this fault occurs, the system disables the driver's seatbelt pretensioner function to prevent unintended deployment.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty driver seatbelt pretensioner (internal short in the squib)
- Short circuit in the pretensioner wiring harness
- Circuit wiring shorted to another circuit or ground
- Loose, corroded, or bent pins in the pretensioner connector
- Damaged airbag control module (RCM) – rare internal failure
3. Symptoms You Will Notice
- Airbag warning light illuminated on the dashboard
- Driver seatbelt pretensioner inoperative
4. Step-by-Step Diagnosis
Scan for codes and verify B1885 is present
Visually inspect the pretensioner connector for damage, corrosion, or loose pins
Measure resistance at the pretensioner connector; compare to manufacturer specifications (typically 2-3 ohms)
Check for shorts to ground or voltage in the wiring between the pretensioner and RCM
If wiring and connector are okay, replace the driver seatbelt pretensioner
If problem persists, test or replace the RCM
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible but not recommended because the driver seatbelt pretensioner will not function in a crash, increasing injury risk. The airbag system may also be compromised. Have it repaired as soon as possible.
How much does it cost to fix?▼
Repair costs typically range from $200 to $600, depending on whether the pretensioner alone needs replacement or if wiring repairs are needed. Labor and parts vary by vehicle.