P0512

Starter Request Circuit

P0512 is a generic OBD-II powertrain diagnostic trouble code: Starter Request Circuit. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P0512
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P0512 means

P0512 is a generic powertrain code that sets when the engine or powertrain control module detects an abnormal condition on the starter request circuit. This circuit carries the crank request from the ignition switch or push-button start module to the control module, which then authorizes and manages starter engagement. The code is not tied to a specific high or low voltage; it flags any signal that is missing, out of range, or otherwise inconsistent with the vehicle's current state.

Because modern start systems route the request through the body control module, immobilizer, and network, a fault here can appear as a no-crank, an intermittent crank, or a signal the module simply cannot validate. The control module often disables automatic starting when P0512 is active to avoid an unintended crank event.

The most common causes are a faulty ignition switch or start-request switch, damaged or corroded wiring and connectors in the request circuit, or a failing starter relay. Diagnosis should always begin by reading codes from all modules and reviewing live data, since companion immobiliser or network codes frequently accompany P0512 and can point to the real root cause before any component is replaced.

Common causes

Most-frequently reported root causes when P0512 is logged.

  • 1
    Faulty ignition switch or push-button start-request switch.
  • 2
    Damaged, chafed, or corroded wiring in the starter request circuit.
  • 3
    Corroded or loose connector at the switch, BCM, or ECM.
  • 4
    Failed or sticking starter relay in the request path.
  • 5
    Neutral safety / clutch position switch fault interrupting the request.
  • 6
    Short to ground or open in the request signal wire.
  • 7
    ECM or PCM internal fault on the starter request input.

Symptoms drivers notice

Malfunction indicator lamp illuminated.
No-crank condition or engine that will not start.
Intermittent or unreliable cranking, often when the fault is intermittent.
Start button or key appears unresponsive at times.
Possible companion immobiliser or network communication codes.

How to diagnose P0512

A typical diagnostic flow when this code is present.

  1. 1
    Read and record codes from all modules, noting any immobiliser or network faults.
  2. 2
    Review freeze-frame and live data for the state of the starter request signal.
  3. 3
    Inspect the request circuit wiring and connectors for damage, corrosion, or chafing.
  4. 4
    Measure the request signal at the module while operating the switch or start button.
  5. 5
    Verify supply voltage and grounds to the ignition switch, relay, and control module.
  6. 6
    Test the starter relay and any neutral-safety or clutch switch in the request path.
  7. 7
    Repair the confirmed wiring, switch, or relay fault, then clear codes and retest starting.

Related powertrain codes

Frequently asked questions

Does P0512 mean my starter motor is bad?

No. P0512 concerns the control-side request circuit, not the starter motor or its high-current cables. The starter itself is usually fine.

Is P0512 always a low-voltage fault?

No. P0512 is a generic circuit code and can be set by a missing, out-of-range, or erratic request signal; it is not limited to a low-voltage condition.

Will my car still start with P0512 stored?

It depends on the fault. Some vehicles crank intermittently while others have a complete no-crank, especially if the module disables starting as a precaution.

Could a weak key fob battery cause P0512?

Usually not directly; a dead fob typically sets an immobiliser code. P0512 points to the physical request circuit, though related network faults can appear together.

Disabling P0512 in software

RaceTune can permanently disable P0512 — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECU families we can disable P0512 on

We hold the DaVinci A2L disable definitions for these families, so the exact P0512 path and mask addresses are mapped. verified marks a confirmed disable definition. We support many more — upload your file and our identifier will match it automatically.

  • Bosch EDC17C66 verified
  • Bosch EDC17CP57 verified
  • Bosch MD1CP004 verified
  • Bosch MG1CP002 verified

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

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