P2505 High Generic / SAE

P2505: Engine Control Module Power Input Signal

Powertrain Auxiliary Inputs, Ventilation and Engine Controls Emissions related

What to do

If several unrelated fault codes have been found, mention this one specifically and ask that it be dealt with first. A control module that is not getting a steady supply misbehaves rather than failing outright, and it records faults naming perfectly good parts — so the rest of the list may well be symptoms of this. The right order is to fix the supply, clear all the codes, drive, and re-read: what comes back is genuine. Ask for the earth connections and the module's power feed to be checked before the module itself is considered, since it is by far the most expensive possibility and rarely the cause.

What this code means

A fault in the supply the engine control module monitors for itself.

The module watches its own power, and the reason is the argument the corpus returns to more than any other. A module short of voltage does not fail cleanly. It carries on running with sensor references sagging, output drivers unable to pull fully, and internal timing marginal — and it records faults naming every healthy component whose reading has drifted as a result. One supply problem presents as a dozen unrelated failures. That case is made at length under P0562 for the system supply and P0882 for a transmission module, and this code is the engine module's own version of it.

Which makes it unusually important to read first in a code list rather than in numerical order. A stored power input fault reframes everything else: those other codes are evidence of this one until proven otherwise, and the sequence that works is to fix the supply, clear everything, drive, and re-read. Whatever returns is real.

The causes are ordinary and mostly cheap — a corroded earth, a connector that has lost tension, a relay with pitted contacts, a fuse holder that has warmed and loosened. The module itself is rarely the answer here, and it is the most expensive of the possibilities.

Likely causes

Start here

Less common

Failing battery · easy

Rare

Faulty engine control module · specialist

Symptoms

Components involved

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

Community experience

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What makes one worth reading:

The car — make, model, year and engine. The same fault behaves differently on each.
What you measured, not only what you replaced.
What actually fixed it — or that nothing did, which is worth knowing too.