B1484: Brake Pedal Switch Circuit Open
The B1484 code indicates that the Body Control Module (BCM) or Powertrain Control Module (PCM) has detected an open circuit in the brake pedal position switch (stop lamp switch) input signal. This means the module is not receiving the expected voltage signal when the brake pedal is pressed, disabling functions such as push-button start, cruise control, shift interlock release, and brake light operation.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty or misadjusted brake pedal position switch (stop lamp switch)
- Open, cut, or corroded wiring in the switch signal circuit
- Blown fuse in the switch power supply circuit (typically the brake light circuit)
- Damaged connector at the switch or BCM/PCM with bent pins or poor connection
- Internal BCM or PCM failure (rare)
3. Symptoms You Will Notice
- Brake lights do not illuminate when pedal is pressed
- Push-button start or keyless ignition may not work
- Cruise control inoperative
- Gear shift lever stuck in Park (shift interlock not releasing)
- Check Engine Light or Brake Warning Light may be on
4. Step-by-Step Diagnosis
Check brake light operation: press pedal and observe if lights come on. If not, suspect switch or fuse.
Inspect the brake pedal switch for proper adjustment and physical damage.
Test the switch with a multimeter: should show continuity when pedal is pressed and open when released.
Check the brake light fuse in the fuse box; replace if blown.
Inspect wiring and connectors between the switch and BCM/PCM for opens, shorts, or corrosion.
If all else is good, test the BCM/PCM input signal; if missing, consider module failure.
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is not recommended because brake lights may not work, increasing the risk of rear-end collision. Additionally, shift interlock and cruise control may be disabled. Have the issue diagnosed promptly.
How much does it cost to fix?▼
Repair costs typically range from $50 to $200 for a switch replacement, plus $50–$100 for diagnosis. Wiring repairs or module replacement can cost more, up to $500 or higher.