OBD-II DTC · SAE J2012
P078A
Shift Timing Solenoid B
What P078A means
P078A is a standard SAE J2012 powertrain diagnostic trouble code with the defined meaning: Shift Timing Solenoid B. This is the OEM-agnostic definition; specific manufacturer interpretation may add detail (subsystem, bank, sensor location) but the core meaning is consistent across all OBD-II compliant vehicles since 1996.
Common symptoms when P078A is active
Cam / crank correlation DTC, VVT actuator circuit MIL, timing-over-advanced or retarded codes after a timing chain service.
Can this code be suppressed via ECU tuning?
Whether this code is safe to suppress depends on the underlying cause. Diagnose first, suppress only after confirming the mechanical issue is benign or rectified.
How to remove P078A with Softechpro V5
Recommended service: DTC OFF (cam/VVT branch) — diagnose timing first. Step-by-step workflow:
- If the engine was recently timed: verify chain alignment + cam sensor wiring before suppressing.
- For benign post-service nuisance codes, Softechpro V5 DTC OFF handles the cam/VVT branch.
- Load .bin, select DTC OFF + cam DTC group, save, flash.
Softechpro V5 supports 1,400+ ECU firmwares across Bosch (EDC15, EDC16, EDC17, MD1, MG1, ME7, MED17), Siemens / Continental (SID, SIMOS, EMS), Delphi (DCM, DDC), and Magneti Marelli platforms.