Powertrain, generic (extended)

P2777 Upshift Switch Circuit High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2777 is the over-voltage counterpart for the upshift switch. GM's 2023 twin-clutch TCM watches the TAPUP input and counts up a timer once it exceeds 4.774 V; after 150 ms above that limit, with supply voltage in the 8.75–18 V band, the code is logged as Type C, so no MIL. Ford's July 2024 OBD summary lists P2777 as out-of-window-high on the TR9070 upshift paddle. Because the released paddle already rests near the top of the range, an open signal circuit, a missing switch ground or a disconnected steering wheel plug pushes the reading over the limit quickly. A short to battery voltage is less common. P2776 is the opposite case, P2775 the implausible but in-range one. The paddle does nothing until the circuit is repaired.

Likely causes

Open signal or ground circuit, steering wheel connector loose
Broken track in the clock spring
Signal wire shorted to a voltage source

Symptoms

  • Upshift paddle without function
  • Driver information message about manual shifting

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€40–500
Time0.5–2 h

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

Parts involved

upshift switchwiring harness

Related codes

P2775P2776P2778P0815P2781

References: gsi.ext.gm.com, fordservicecontent.com.