OBD-II Code · Computer
P2509
PCM Power Input Signal Intermittent
Severity
high
Left alone, this one tends to take other parts with it.
Can you drive it
Not for long
Driving on this one risks further damage. Get it to a shop rather than carrying on with it.
Indicative cost (USD)
$30–$400
Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
Intermittent power to PCM.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then work the likely-causes list in the order shown.
That order is what a shop checks first for this code — wiring and connections before the component they run to, because a connector costs nothing to inspect and is a common answer.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Stalling
- No start
Likely causes
- Loose battery terminalMost common
- Failed relay
Look up another code
P2509 — frequently asked
What does a P2509 code mean?
Intermittent power to PCM.
What causes a P2509 code?
Common causes: Loose battery terminal; Failed relay.
What are the symptoms of a P2509 code?
Typical symptoms: Stalling; No start.
Is it safe to drive with a P2509 code?
Not for long. Driving on this one risks further damage. Get it to a shop rather than carrying on with it. Estimated repair: $30-$400.
How do I diagnose a P2509 code?
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed. 1. Note every code that is set, not just this one. 2. Read the freeze frame — the conditions the fault was recorded under. 3. Confirm the fault is current rather than history. 4. Then work the likely-causes list in the order shown.
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