Skip to content
Book on WhatsApp

P2543

Power Demand Signal Circuit

The ECU detects an electrical fault on the power demand input signal used to coordinate accessory loads (e.g. AC compressor, alternator load). The signal is missing or implausible.

  • Check engine light: Yes
  • Emissions related: No
  • Repair difficulty: medium

Common causes

Ordered by how often each turns out to be the cause.

  • Open signal wireCommon
  • Fault in requesting modulePossible

Parts involved

  • Power Demand Signal Module
  • Hvac Module

P2543 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.