What Does P0512 Mean?
The starter motor request circuit has a malfunction. The PCM monitors the starter relay control circuit and has detected an abnormal condition — either the circuit is not energizing the starter when commanded, or the starter circuit is active when it should not be. The driver may experience a no-crank condition, intermittent starting, or in rare cases the starter may remain engaged after the engine starts.
Common Causes
30%
Faulty starter relay not responding to PCM commands
25%
Open or high-resistance wiring in the starter control circuit
20%
Failed ignition switch or start button not sending proper signal to PCM
15%
Weak battery or poor battery cable connections causing insufficient voltage for starter engagement
10%
PCM starter control output circuit failure
Diagnostic Steps
1
Check battery voltage with a multimeter — it should be 12.4V+ with the engine off. Perform a load test to verify the battery can sustain cranking current.
2
Monitor the starter request PID while turning the key to the start position — verify the PCM receives the start signal input.
3
Check for voltage at the starter relay control coil terminal when the key is in the start position — if missing, trace the circuit from the ignition switch through the PCM to the relay.
4
Verify the starter relay clicks when commanded — swap with an identical relay in the fuse box to rule out relay failure.
5
Inspect all battery cable connections at both the battery terminals and the starter/engine ground points — clean and tighten as needed. Voltage drop should be less than 0.5V on each cable during cranking.
Estimated Repair Cost
$25 - $500
Parts + labor, varies by vehicle and location
The starter motor request circuit has a malfunction. The PCM monitors the starter relay control circuit and has detected an abnormal condition — either the circuit is not energizing the starter when commanded, or the starter circuit is active when it should not be. The driver may experience a no-cra...
The most common cause of P0512 (Starter Request Circuit) is: Faulty starter relay not responding to PCM commands
Typical repair costs for P0512 range from $25 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The primary risk is being stranded if the vehicle will not start. If the starter remains engaged after the engine starts, shut off the engine immediately to prevent starter motor damage. The vehicle is safe once running, but unreliable starting should be addressed before relying on the vehicle for important trips.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0512 to identify the root cause.
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Quick Info
Category
Powertrain
System
Starting System
Difficulty
Type
Generic (SAE)
Recommended Tools
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