Powertrain, generic (extended)

P257E Engine Hood Switch Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modeNo

P257E says the hood switch signal has dropped below its lowest valid level, which usually means the signal wire touches ground or the switch is shorted inside. GM's 2018 engine table 18OBDG04 sets it for a resistance-coded switch at 325 ohms or less, the 2019 hybrid table 19OBDG01 at 14.6 % of range or less, each with 80 failures in 100 samples and Type B. A Chrysler STAR case for the 2017–2018 Pacifica describes a lit hood ajar lamp, a dead stop-start system and P257E after a repair, caused by the hood ajar plug and the horn plug at the latch having been swapped – a dead horn gives it away. GM's engineering note PIE0834 lists the code on its 2022–2025 electric pickups and SUVs with front hood latch trouble. Depending on design a grounded line can look like an open hood.

Likely causes

Hood switch signal wire chafed to ground near the latch
Hood switch and horn connectors swapped after front-end repair
Switch shorted internally by water or impact damage

Symptoms

  • Hood ajar indicator on with the hood shut
  • Engine stop-start inoperative
  • Check engine lamp on

Repair estimate

DifficultyMediumDIY possible
Parts and labour€20–250
Time0.3–2 h

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

Parts involved

hood switch

Related codes

P257DP257FP254F

References: gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.