Brake Booster Pressure Sensor Circuit
2018-2018 Lincoln MKX 3.7L V6
The 2018 Lincoln MKX is equipped with a 3.7L V6 engine. Below you'll find detailed c0090 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
Malfunction in the brake booster vacuum or pressure sensor circuit.
Symptoms
- Brake warning light on
- Hard brake pedal
- Increased stopping distance
- Check Engine Light may also be on
Common Causes
- Faulty brake booster pressure sensor
- Vacuum hose leak
- Wiring damage
- Brake booster vacuum pump failure on diesel/turbo vehicles
Diagnostic Steps
- Test brake booster vacuum with gauge
- Check vacuum hose to booster
- Test pressure sensor signal
- Inspect wiring and connector
- Check engine vacuum source
Repair Notes
Repair vacuum leak or replace pressure sensor. On diesel vehicles, check vacuum pump.
Related Codes
Other Chassis Codes
- C0021LF Wheel Speed Sensor Range/Performance
- C0021LF Wheel Speed Sensor Range/Performance
- C0022RF Wheel Speed Sensor Range/Performance
- C0022RF Wheel Speed Sensor Range/Performance
- C0023LR Wheel Speed Sensor Range/Performance
- C0023LR Wheel Speed Sensor Range/Performance
- C0024RR Wheel Speed Sensor Range/Performance
- C0024RR Wheel Speed Sensor Range/Performance
- C0025LF Wheel Speed Sensor Circuit Intermittent
- C0025LF Wheel Speed Sensor Circuit Intermittent
C0090 on Other Vehicles
Lincoln Aviator
2003-2003 4.6L V8 DOHC
Lincoln Aviator
2004-2004 4.6L V8 DOHC
Lincoln Aviator
2005-2005 4.6L V8 DOHC
Lincoln Aviator
2020-2020 3.0L Twin-Turbo V6
Lincoln Aviator
2020-2020 3.0L V6 Twin Turbo
Lincoln Aviator
2020-2020 3.0L V6 Twin Turbo Hybrid
Lincoln Aviator
2021-2021 3.0L Twin-Turbo V6
Lincoln Aviator
2021-2021 3.0L V6 Twin Turbo
Common Questions
What does code C0090 mean on a 2018-2018 Lincoln MKX?
C0090 stands for "Brake Booster Pressure Sensor Circuit". Malfunction in the brake booster vacuum or pressure sensor circuit.
What are the symptoms of C0090 on a Lincoln MKX?
Common symptoms of C0090 include: Brake warning light on, Hard brake pedal, Increased stopping distance, Check Engine Light may also be on.
What causes C0090 on a 2018-2018 Lincoln MKX?
Common causes of C0090 include: Faulty brake booster pressure sensor, Vacuum hose leak, Wiring damage, Brake booster vacuum pump failure on diesel/turbo vehicles.
Last updated: March 2026