What does it mean?
B2133 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Ignition Run/Start (Remote Start) Control Circuit Low .
Symptoms
- Brake system warning lamp does not illuminate during the bulb check, or stays on permanently
- Electric parking brake or brake assist function disabled or in a reduced mode
- Warning message in the driver information display
- Remote start refuses to work on applications using the ignition variant
- Fault returns after clearing, sometimes only when the lamp is commanded on
- Driver has no reliable brake warning, which is a safety concern
Likely causes
- Failed warning lamp bulb or LED, which the module sees as an open output
- Open circuit between the module driver and the instrument cluster lamp
- Lamp output wire shorted to ground so the driver cannot control the lamp
- Corroded or backed out terminal at the cluster connector
- Instrument cluster internal fault on the lamp circuit
- Ignition run/start control wire pulled low by a chafed conductor or a failed remote start relay
- High resistance module ground affecting all lamp drivers on that connector
- Body or brake control module output driver failure once the wiring is proven
How to fix it
- Confirm the manufacturer definition and the correct output pin for this vehicle
- Watch the cluster bulb check at key on, a missing lamp during the sweep points at the lamp or its circuit
- Use the scan tool output test to command the lamp on and off while watching the cluster
- Backprobe the lamp output at the module and measure voltage in both commanded states
- Check continuity between the module and the cluster with both connectors off
- Inspect the cluster connector for corrosion and pushed out terminals
- For the ignition variant, check the relevant fuse, relay and remote start wiring for a short to ground
- Repair the wiring or replace the lamp, cluster or module as proven, then verify the lamp behaves correctly through a full key cycle