B1890: Airbag Warning Lamp Short to Battery
Diagnostic trouble code B1890 indicates a short circuit to battery positive voltage in the passenger airbag deactivation (PAD) indicator lamp circuit. This lamp illuminates on the dashboard to inform the driver when the passenger airbag is disabled, typically due to an empty seat or a system fault. The Restraint Control Module (RCM) detects that the voltage on this circuit is higher than expected, meaning the lamp circuit is shorted to a constant 12V source. This fault prevents the PAD indicator from functioning correctly, potentially hiding critical safety information from the driver about the passenger airbag status.
1. Commonly Affected Makes
2. Most Common Causes
- Wiring in the PAD lamp circuit shorted to battery positive voltage
- Internally shorted PAD indicator bulb or LED
- Damaged connector or harness in the instrument panel with pins contacting battery voltage
- Faulty Restraint Control Module (RCM) with internal short in lamp driver circuit
- Short circuit in the instrument cluster illumination circuit related to the PAD indicator
3. Symptoms You Will Notice
- Passenger airbag deactivation (PAD) warning lamp stays on or off regardless of passenger seat status
- Airbag warning light on the dashboard may be illuminated
4. Step-by-Step Diagnosis
Scan the RCM for stored codes and verify B1890 is present
Visually inspect the PAD indicator lamp wiring and connector for damage or shorts to power
Test the PAD lamp circuit for continuity to battery voltage with a multimeter
Check the instrument cluster for internal shorts or replace the cluster if necessary
If wiring and cluster are okay, test the RCM output; replace RCM if faulty
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible, but the passenger airbag status may not be correctly indicated, which is a safety concern. It is recommended to have the issue diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $100 to $400, depending on whether the fix involves wiring repair, instrument cluster replacement, or RCM replacement.