ECM/PCM Power Input Signal High
The P2508 code means the vehicle's onboard diagnostic system has detected: ECM/PCM Power Input Signal High. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $200 - $800 (parts and labor)
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What Are the Symptoms of P2508?
- Erratic engine behavior
- Random warning lights
- Electrical system voltage spikes
- Premature electrical component failure
What Causes P2508? (Most Likely First)
- Overcharging alternator Very High
- Faulty voltage regulator High
- Short to battery voltage in ECM power circuit Moderate
- Aftermarket accessories causing voltage spikes Low
Can I Still Drive with P2508?
Short distances only. P2508 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
Can high voltage damage my ECM?
Yes. Sustained over-voltage can damage internal circuits within the ECM, leading to expensive replacement.
What causes voltage spikes in the ECM circuit?
Most commonly a failing voltage regulator on the alternator, but also loose connections or aftermarket electrical accessories.
Should I disconnect the battery if overcharging?
It is safer to have the vehicle towed. Overcharging can damage multiple electronic modules simultaneously.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P2508?
-
Measure voltage at ECM power input with engine running
-
Test alternator output voltage regulation
-
Check for aftermarket wiring tapped into ECM circuit
-
Inspect voltage regulator under varying loads
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)
Which Vehicles Commonly Get P2508?
- 2010-2020 Toyota Highlander
- 2012-2019 Honda Accord
- 2008-2018 Ford Explorer
- 2011-2020 Chevrolet Traverse
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