ECM/PCM Power Input Signal Range/Performance
The P2506 code means the vehicle's onboard diagnostic system has detected: ECM/PCM Power Input Signal Range/Performance. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- moderate
- Estimated cost
- Varies - diagnose the named circuit before replacing parts
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Common Symptoms
- Check Engine Light on
- Drivability may be normal - many circuit faults show no symptom the driver notices
- The affected system may fall back to a default strategy, costing power or economy
- Related values implausible or frozen on a scan tool
Probable Causes (Ranked by Likelihood)
- Fault in the ECM/PCM Power Input Signal circuit: a reading that is present but implausible - the value does not track what the module expects High
- Damaged wiring, a chafed harness, or a corroded connector at the ECM/PCM Power Input Signal High
- Failed ECM/PCM Power Input Signal Moderate
- Control module input/driver fault (rule this out last - it is the least common) Low
Common Fixes by Vehicle
What techs usually find when diagnosing P2506 on specific vehicles — tap your vehicle for the fix and the exact part:
2008-2016 Ford F-150/Escape/Focus easy DIY
P2506 = battery voltage saw an unexpected disconnect or dip. Most common cause: loose battery terminal or corroded ground cable. Remove both cables, clean with wire brush + baking soda, re-torque to 5 ft-lb, and apply terminal protectant.
Labor: 20 min
2010-2018 Ford Fusion/Escape 2.0L/2.5L moderate DIY
Failed alternator causing voltage to drop below 11V under load. Load-test with a carbon-pile tester -- should hold 13.6-14.4V at 30A load. If it sags, replace alternator (Motorcraft or ACDelco OE). Aftermarket low-cost alternators often fail P2506 quickly.
Labor: 1-2 hours2008-2017 VW Passat/Audi A4/Q5 easy with VCDS DIY
VW/Audi BEM (battery energy management) module fault. After battery replacement the new battery MUST be coded to the car via VCDS/ODIS with the correct capacity and chemistry. Without coding, P2506 is inevitable within a few weeks. Note: VCDS is sold only by Ross-Tech directly (ross-tech.com). Ross-Tech warns that the cheap 'VCDS' cables sold on marketplaces are clones their software will not run, so buy it from them rather than from a search result.
Labor: 10 min codingFrequently Asked Questions
What does P2506 mean?
P2506 is a generic OBD-II code defined by SAE J2012 as "ECM/PCM Power Input Signal Range/Performance". It means the control module detected a reading that is present but implausible - the value does not track what the module expects
Can I keep driving with P2506?
Yes for normal use, but get it diagnosed - the system is running on a fallback strategy and a small wiring fault left alone tends to become a bigger one.
Does P2506 mean the same thing on every car?
Yes. P2506 is in the generic (SAE J2012) range, so the definition is standardized across manufacturers. The specific component location and repair procedure still vary by vehicle - check your service information.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
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Read the code and freeze-frame data, then watch the ECM/PCM Power Input Signal live on a scan tool.
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Inspect the connector and harness at the ECM/PCM Power Input Signal before replacing anything - wiring and corrosion cause most of these.
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Back-probe the circuit and compare signal, ground, and reference voltage against the service-manual values.
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Wiggle-test the harness while watching the live value if the fault is intermittent.
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Clear the code and confirm with a road test that covers the conditions in the freeze frame.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Commonly Affected Vehicles
- All OBD-II vehicles - this is a generic (SAE J2012) code with the same meaning across makes
Related Codes
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