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DTC code page

P0512: Starter Request Circuit

Quick answer: The PCM detected a fault in the starter request input circuit.

Drivers also search this fault as starter request circuit fault, start request signal code, ignition start request problem.

Severity: high Family: powertrain Related paths: 11
Meaning

What P0512 usually means

P0512 is about the request to crank, not the starter motor’s mechanical ability once power reaches it. The PCM is saying the start request signal from the ignition switch, body module, or related start-authorization circuit does not make sense. That makes this a very useful bridge code between traditional starter diagnosis and newer module-controlled start systems.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Decide whether the vehicle is key-start or push-button start, because the request path changes the diagnostic route immediately.
  • Check whether the PCM or BCM is actually seeing a start request on scan data if the platform supports it.
  • Look for companion park-neutral, brake-switch, or immobilizer symptoms that explain why the request is being blocked.
Driving risk

Can you keep driving?

P0512 can leave the vehicle unable to recognize a valid start command. If the request is being lost intermittently, expect unpredictable no-start events.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Symptoms

Common symptoms

Likely causes

Common causes behind this code

  • Faulty ignition-switch or push-button start request input
  • Wiring problem between the start request source and PCM or BCM
  • Body control module or start-authorization logic fault
  • Poor connector fit, corrosion, or intermittent open in the request circuit
  • Battery-voltage instability confusing the request signal

Cause phrases often tied to this code: starter request, ignition switch, body control module, push button start, start authorization.

Diagnostic order

Suggested workflow

  1. Verify the start request input changes state when the key or button is used.
  2. Inspect request-circuit wiring, connector condition, and related fuses.
  3. Check whether the body module, brake switch, clutch switch, or immobilizer is preventing the request from reaching the PCM.
  4. Compare commanded start request with actual starter relay activity.
  5. After repair, confirm the request signal is recognized consistently over repeated starts.
Avoid guesswork

Common mistakes

  • Replacing the starter when the module never received a proper start request to begin with.
  • Ignoring push-button start or BCM involvement on newer vehicles.
  • Treating P0512 like a simple dead-battery complaint without checking request data.
Repair path

Practical fix guidance

  • Repair the start-request switch, wiring, or module-side logic fault proven by testing.
  • If authorization inputs such as brake, clutch, or park-neutral are the real blocker, fix those instead of chasing the starter motor.
  • Retest several starts in different conditions to verify the request path is reliable.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0512

Useful when the driver knows the wording but not the exact DTC yet.

  • starter request circuit fault
  • start request signal code
  • ignition start request problem
Related search intent

Queries this page can answer naturally

  • P0512 code meaning
  • what does P0512 mean
  • starter request circuit symptoms
  • ignition switch start request code
FAQ

Quick questions about P0512

Is P0512 the same as a bad starter?

No. It usually means the request to start is not being interpreted correctly, which is upstream of the starter motor itself.

Can a push-button start system trigger P0512?

Yes. Any fault in the request or authorization path can set it, including push-button start designs.

Why is scan data useful for P0512?

Because seeing whether the module recognizes the start request quickly separates a switch or input fault from a relay or starter fault.