C0301 code meaning
Air Suspension Compressor Relay
What C0301 means
No reachable J2012 table, no GM keyword list such as PIP5094, no AA1Car chart and no NHTSA bulletin carries C0301. Makers that document this fault use their own numbers. Mercedes-Benz stores open-circuit compressor actuation on AIRMATIC cars as C1562 and, after moisture froze in the compressor and the start current blew the 40 A fuse, replaces compressor, fuse and relay together. Lexus reports C1752 on the 2013–17 LS460 when water corrodes the height control compressor, and Volvo tells dealers to swap fuse and compressor on 2017–18 models. The relay switches the compressor's heavy current on command of the suspension module. A worn compressor overloads its contacts; a relay that sticks closed keeps it running and can overheat it.
C0301 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0301
- Air suspension warning message, compressor silent
- Vehicle sinks or leans after standing
- Compressor runs continuously when the relay sticks
Common causes of C0301
- Most likelyRelay contacts burnt or welded by excessive compressor current
- PossibleWorn, seized or water-damaged compressor drawing too much current
- PossibleBlown compressor fuse or corroded relay socket and wiring
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Compressor relayAir compressorAir suspension module
What each part of C0301 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 01 | The exact fault in that area. |
What to do next
- Note C0301 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0301
What does C0301 mean?
C0301 means "Air Suspension Compressor Relay". No reachable J2012 table, no GM keyword list such as PIP5094, no AA1Car chart and no NHTSA bulletin carries C0301. It is a generic code, so it means the same on every make.
Is it safe to drive with C0301?
Drive gently and only to a workshop. With C0301 the car can go into limp mode (reduced power) to protect itself.
Will C0301 fail an emissions test?
C0301 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0301 to fix?
Difficulty: medium. A typical repair takes 0.3 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C0301 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.