U0139Lost Communication With Suspension Control Module B
- Generic OBD-II code · Network
- Turns on the check-engine light
- How the car detects it
- U0139 reports lost contact with suspension control module B, at GM the semi-active damping system (SADS). GM's 2025 tables let the ECM watch two SADS messages, $035 with a 10 s limit and $364 with 325 ms, and set U0139 as Type B with the MIL after two trips; the EBCM treats missing damper frames for 250 ms as Type C. Bulletins PIT6007 and PIT6007A (2020–2024 Corvette, Escalade, Tahoe, Suburban, Yukon with Magnetic Ride Control) describe a check-engine lamp with U0139 in the ECM and no other symptom, cleared by pulling the K19 module fuse for one minute. PIT5457 lists it with high resistance in wake-up circuit 5986. Saab and Ford's 2014 list carry the code too. Damping then usually stays at a fixed setting.
- What you may notice
- Check-engine lamp, often without any other symptom (GM)
- Service Suspension message, adaptive damping inactive
- Harsher or softer ride than usual
- Likely causes
- LikelySuspension module software locks up, recovers after a fuse reset (GM PIT6007)
- PossibleHigh resistance or open in the module wake-up line (GM circuit 5986)
- PossibleFuse, supply, ground or CAN wiring of the damping module faulty
- RareSuspension control module B internally faulty
- Repair
- Medium · Usually a job for a workshop.Typical cost: €30 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.