Brake Booster Pressure Sensor Fault
There's a problem with the brake booster pressure sensor or circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The brake booster pressure sensor measures how much vacuum pressure is in the brake booster. If it detects a pressure that’s too high or too low, it sends this info to the engine control unit (ECU) to help with brake performance and stability. If the sensor fails, you might notice harder pedal feel or less effective braking.
What the computer is actually seeing
The ECU expects a specific voltage range from the brake booster pressure sensor, usually between 0.5 to 4.5 volts, corresponding to varying vacuum pressures. A fault occurs when the signal is outside this expected range, indicating a malfunctioning sensor or circuit.
What a healthy reading looks like
Vacuum pressure should be between 18 to 22 inches of mercury (Hg) in most vehicles under normal conditions; the sensor output should be within 0.5V to 4.5V depending on the brake booster pressure.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check for any visible damage to wiring and connectors related to the brake booster pressure sensor. If damaged, repair or replace as needed. Decision: Is wiring okay? Yes: Go to step 2. No: Repair wiring and retest.
Common causes
- Faulty brake booster pressure sensor
- Damaged wiring or connectors in the sensor circuit
- Vacuum leaks in the brake system
- Failed brake booster
- ECU software issue
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderately. You may experience reduced braking efficiency, so it's best to fix it soon.
Will this code keep coming back?
If the underlying issue isn't resolved, yes, it can return after clearing.
Why is this code paired with C1420?
C1420 indicates a fault in a related system, often linked to braking performance. Investigate both codes together.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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