Powertrain Control Module (PCM) Power Input Signal Intermittent
The PCM is not receiving a stable power input signal.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
Inside the computer, there's a constant need for power to function properly. If that power is weak or goes away for a moment, it gets confused and can throw trouble codes.
What the computer is actually seeing
The PCM monitors voltage levels from its power input circuit. It expects a steady voltage around 12V. If this drops significantly or has interruptions, it sets the P0680 code.
What a healthy reading looks like
Steady voltage at PCM power input should be between 12V to 14V with the engine running.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check battery voltage; should be 12.4V or higher. If low, charge or replace battery.
- 22. Inspect the PCM connectors; look for corrosion, damage, and ensure they're seated properly.
- 33. Test wiring for continuity and shorts; measure voltage at the PCM power pin while the ignition is on. Should read 12V-14V.
- 44. Check for blown fuses related to the PCM power circuit. Replace any blown fuses and retest.
- 55. If everything checks out but the code persists, consider testing or replacing the PCM.
Common causes
- Faulty PCM
- Corroded or loose connectors
- Bad wiring or shorts
- Weak battery or alternator issues
- Blown fuses in the PCM power circuit
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It may be drivable, but you might experience electrical issues or drivability problems. Fix it soon.
Will this code come back?
If the underlying issue isn't fixed, the code will likely return after clearing it.
Why does this code pair with others?
Multiple codes can indicate systemic electrical problems, often related to voltage supply issues.
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