Starter Request Circuit Malfunction
The P0512 code indicates a problem in the starter request circuit, which is the electrical path that carries the start signal from the ignition switch or body control module to the starter relay. This circuit includes the ignition switch, wiring, connectors, and the starter relay itself. When the powertrain control module (PCM) detects an unexpected voltage or no voltage on this circuit during cranking, it sets this code. Common causes include a faulty ignition switch, damaged wiring, a bad starter relay, or a failing PCM. Symptoms may include the engine not cranking, intermittent starting issues, or the starter running continuously.
01. Most Common Causes
- Faulty ignition switch
- Damaged or corroded wiring/connectors in the starter request circuit
- Defective starter relay
- Failed PCM (rare)
02. Symptoms You Will Notice
- Engine does not crank when key is turned
- Intermittent starting problems
- Starter stays engaged after engine starts
- No start condition
03. Step-by-Step Diagnosis
Step 1: Scan for other codes and check freeze frame data.
Step 2: Inspect the starter relay and ignition switch for proper operation.
Step 3: Test voltage at the starter relay control circuit with key in START position.
Step 4: Check for continuity and shorts in wiring between ignition switch, relay, and PCM.
Step 5: If all else passes, test PCM output or replace PCM.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, it is not safe because the vehicle may not start or could stall unexpectedly. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
Typically between $50 and $150 for parts and labor, depending on the cause. A faulty ignition switch or relay is inexpensive, but PCM replacement can cost more.