Powertrain, generic (extended)

P2778 Upshift Switch Circuit Intermittent/Erratic

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2778 is meant for an upshift switch signal that jumps around or drops out briefly instead of staying in one state. No manufacturer documents P2778 publicly. GM's 2023/2024 twin-clutch TCM and Ford's TR9070 split the same paddle input into low, high, implausible and stuck faults (P2775–P2777, P0815) but list no intermittent check, so on those cars a flickering contact will rather end up as one of these. CARB expects inputs to be watched for circuit and rationality faults, which is the frame this code fits. Practical causes are a clock spring with a cracked track that opens at certain wheel angles, a loose crimp in the column connector, or a worn paddle contact. Symptoms come and go: occasional ignored upshifts or unwanted gear requests.

Likely causes

Clock spring track cracked, opening at certain steering angles
Loose terminal or poor crimp in the column or wheel connector
Worn or bouncing contact in the paddle

Symptoms

  • Upshift requests occasionally ignored
  • Occasional unwanted upshift requests
  • Fault comes and goes, often depending on steering angle

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–600
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

upshift switchwiring harness

Related codes

P2775P2776P2777P0815P2782

References: law.cornell.edu, gsi.ext.gm.com, fordservicecontent.com.