P2505

ECM/PCM Power Input Signal

Q: Is it safe to drive with P2505?

Not really. An unstable power feed to the ECM can make the engine stall or refuse to start with little warning. Diagnose it before relying on the car.

Q: Can I just clear P2505?

Clearing it does not fix the power or ground problem, and it will return — often along with a stall or no-start. Repair the circuit first.

ECM power supply Generic OBD-II High

What it means

P2505 means the ECM has detected a problem with its own power input — the voltage feeding the engine computer is missing, low, or unstable. Because the ECM controls everything, a bad power feed or ground can cause stalling, hard starting, or a no-start, and often triggers several unrelated codes at once. Start diagnosis at the battery, grounds, fuses, and the ECM power relay.

High

Can I keep driving? Risky — a faulty ECM power feed can cause stalling, hard starting, or a no-start, so diagnose it promptly.

Real-world scan data

Seen in

162

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P2505 scans

U0037in 44.4% of scans

P0704in 37.0% of scans

P0850in 35.8% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Intermittent stalling or the engine cutting out
Hard starting or an intermittent no-start
Multiple unrelated sensor codes stored at once
Erratic gauges or electrical behavior

Common causes

Most likely first

Corroded or loose ECM power connector or groundLikely
Blown fuse or a failing ECM power relayCommon
Weak battery, loose battery terminals, or a charging-system faultCommon
Damaged power or ground wiring to the ECMLess often
Faulty ECM (least common)Less often

How to diagnose & fix

Work through it in order

Scan and read freeze-frame data, then load-test the battery and check the terminals.
Check the ECM fuses and swap-test or measure the ECM power relay.
Inspect the ECM power and ground connectors for corrosion or looseness.
Voltage-drop test the ECM power feeds and grounds while cranking and running.
Repair the wiring or relay found at fault; replace the ECM only as a last resort.

FAQ

Quick answers

Is it safe to drive with P2505?+

Not really. An unstable power feed to the ECM can make the engine stall or refuse to start with little warning. Diagnose it before relying on the car.

Can I just clear P2505?+

Clearing it does not fix the power or ground problem, and it will return — often along with a stall or no-start. Repair the circuit first.

Read & clear P2505 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX