Fault Family System: Chassis (C-Codes) 11 SAE Codes

Brake Vacuum Sensor Circuit

Diagnostic & Technical Explanation

Code C0547 (Vacuum Sensor Supply Voltage Circuit/Open) sets when the module cannot get a valid signal from the sensor that measures vacuum available to the brake booster -- the sensor's supply voltage is missing, the signal circuit reads open/low/high, or two redundant vacuum sensor channels disagree with each other. This sensor is especially important on turbocharged and hybrid vehicles that cannot always rely on steady engine vacuum, since the module may need to run an auxiliary vacuum pump when the reading drops too low. Physical causes include a cracked vacuum line at the sensor tap, a corroded connector, or a failed sensor diaphragm.

These 11 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 11 times.

Codes in this family (11)

Code	Definition	Repair coverage
C0547	Vacuum Sensor Supply Voltage Circuit/Open	4 ranked fixes
C0548	Vacuum Sensor Supply Voltage Low	4 ranked fixes
C0549	Vacuum Sensor A Circuit/Open	4 ranked fixes
C054A	Vacuum Sensor A Range/Performance	4 ranked fixes
C054B	Vacuum Sensor A Circuit Low	4 ranked fixes
C054C	Vacuum Sensor A Circuit High	4 ranked fixes
C054D	Vacuum Sensor B Circuit/Open	4 ranked fixes
C054E	Vacuum Sensor B Range/Performance	4 ranked fixes
C054F	Vacuum Sensor B Circuit Low	4 ranked fixes
C0550	Vacuum Sensor B Circuit High	4 ranked fixes
C0561	Vacuum Sensor A/B Correlation	4 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

Need All 15,886 Codes as Data?

Pipe-delimited CSV, Apache Parquet and a relational SQLite database, with commercial application rights and instant download. Built for scan tools, shop software and research - not assembled one web page at a time.

License OEM Complete · $149 Standard (SAE only) · $49

$49 Standard: 9,249 SAE codes · $149 OEM Complete: all 15,886 codes, including 6,637 OEM codes across 32 makes · $149 Heavy Duty: 4,212 fault pairs (J1939) · one-time · compare tiers