Powertrain, generic (extended)

P2537 Ignition Switch Accessory Position Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2537 reports that the accessory or accessory wake-up input sits low where a high level is expected. GM documents it in detail: on the 2016 Volt the ECM fails it when the accessory input is false while the propulsion system has been active for more than 0.5 s; it is a Type B fault over 2 trips, and the 6-speed TCM tables evaluate the same input with no MIL. GM bulletin PIT5308 for 2014–2015 Silverado, Sierra, Tahoe, Yukon, Suburban and Escalade links P2537 to remote start, and a power liftgate that only works with the ignition on, because ECM and TCM do not get the 12 V accessory wake-up from the BCM on circuit 5985; that wire is checked with a voltmeter, not a test lamp. A diesel follow-up (PIT5308A) adds a blower that keeps running after shutdown.

Likely causes

Open or high-resistance accessory wake-up circuit between BCM and ECM/TCM
Body control module not driving the wake-up output
Poor terminal contact at ECM or TCM connector

Symptoms

  • Remote start inoperative
  • Power liftgate works only with ignition on
  • Blower may keep running after engine shutdown (diesel)

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€20–400
Time0.5–3 h

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

Parts involved

ignition switchwiring harness

Related codes

P2536P2538P2534

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