01772: How to Diagnose & Fix — Brake Light Switch (VAG)
2 vehicles · 1 makes · $800-$3,500 repair
How to diagnose and fix 01772: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Audi S6 · 2013–2013
Audi TSB 2018765/8 covers 2013 C7 S6 vehicles with air suspension when ride-height adjustment is unavailable, the compressor continues running after shutdown and locking, or the system lowers the car and displays a warning. The bulletin identifies a compressor or J403 relay diagnostic path; it does not establish a universal leaking-strut or valve-block defect.
Common Symptoms
- Self-leveling adjustment is unavailable in the MMI
- Air-suspension compressor continues after shutdown and locking
- Vehicle is lowered to its lowest position
- Air-suspension warning light
How to Fix
Have an Audi-qualified technician test the air-suspension compressor and inspect relay J403. Audi directs replacement of both the compressor and relay when the relay has severe contact erosion or an overheated strand; when the compressor sounds normal and the relay has only minor contact marks, replace the relay only. A sagging corner or leak-down condition requires separate leak localization before any strut is replaced. Do not order the former strut or compressor recommendations from this card.
Sources for this issue (1)
Audi SQ7 · 2020–2024
The Audi SQ7's sport-calibrated adaptive air suspension system (4M chassis, shared with Q8/SQ8/Bentley Bentayga/Lamborghini Urus) develops failures in air springs, the compressor, valve block, and height sensors. Compressors typically last 80,000-100,000 km but high ambient temperatures, frequent off-road use, or air leaks cause premature failure. Air spring leaks cause the compressor to run continuously (even with engine off), eventually burning it out. The SQ7's significant curb weight (5,500+ lbs) stresses the system more than lighter vehicles on the same platform.
Common Symptoms
- Vehicle sitting low on one or more corners overnight
- Air suspension fault warning on dashboard
- Compressor running audibly with engine off
- Hissing noise from wheel wells (air spring leak)
- Ride quality noticeably degraded or excessively bouncy
- Height adjustment no longer responds
- Error codes 02250 or 01447 in diagnostic scan
How to Fix
Diagnose specific failed component: air springs leak most commonly, followed by compressor burnout, valve block faults, and height sensor failures. Air spring replacement ($800-$1,500 per corner at independent shop). Compressor replacement ($1,200-$2,500 installed). Valve block: $500-$1,000. Height sensor: $200-$400. Check for air leaks first using soapy water spray before replacing the compressor - a $200 air spring seal may be causing a $2,000 compressor to overwork and fail. Aftermarket solutions from Arnott offer cost savings. Converting to conventional springs ($1,500-$2,500) eliminates future air suspension costs but sacrifices ride height adjustment.
Sources for this issue (1)
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01772 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does 01772 mean?
01772 stands for "Brake Light Switch (VAG)." VAG-specific brake light switch fault code. Affects cruise control and brake light operation.
What are the most common causes of 01772?
The most common causes of 01772 are: Failed brake light switch, Switch out of adjustment, Wiring issue, Switch plunger worn, Connector fault. The specific cause varies by vehicle.
How much does it cost to fix 01772?
Repair costs for 01772 range from $800 to $3,500, depending on the vehicle and root cause.
Which vehicles are affected by 01772?
Au7o has documented 01772 across 2 vehicle models from 1 manufacturers: Audi.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.