What does it mean?
B1890 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Passenger Air Bag Deactivation (PAD) Indicator Circuit Short To Power Supply .
Symptoms
- PASSENGER AIR BAG indicator stays lit all the time, or both ON and OFF segments appear lit
- The indicator no longer follows the PAD switch position or the occupant status
- Air bag warning lamp is usually on as well
- Driver cannot rely on the displayed passenger air bag status
- Fault often appears after dash, console or audio work
Likely causes
- Indicator control wire chafed against a bracket and touching a powered circuit behind the dash or console
- Water from a drink spill, a leaking heater core or a windscreen leak bridging pins in the indicator connector
- Aftermarket accessory wiring tapped into or routed with the indicator circuit
- Faulty PAD indicator assembly with an internal short to its supply
- Damaged connector letting the control terminal touch an adjacent powered terminal
- Restraint control module output driver shorted internally
How to fix it
- Observe air bag safety precautions before removing trim or unplugging any restraint connector
- Note the exact indicator behaviour, since a permanently lit lamp points to a short to power rather than an open circuit
- Unplug the indicator and check the harness side control wire for voltage with the ignition on; voltage present confirms the short
- Command the indicator off with a scan tool bidirectional test and see whether the lamp still stays lit
- Inspect the connector for spilled liquid, corrosion and terminals bridged by moisture, then dry and clean it
- Trace the control wire behind the dash and console looking for chafe points against brackets and for aftermarket splices
- Replace the restraint control module only when the circuit is proven clean with everything disconnected