P0512: Starter Request Circuit

What it means

The starter request input - the signal that tells the ECU the driver wants to crank the engine - shows a circuit fault. Without it the engine cannot be started under software-managed start strategies (stop-start, push-button, immobiliser-coordinated start).

At a glance

• Usually lights the check-engine light

How it works

The starter request circuit carries the driver's request to crank the engine to the control module. P0512 sets when the module detects an electrical fault in that request signal, which can prevent software-managed starting from recognizing the request.

Common causes

Most likely first.

1. Faulty starter request switch or button
2. Open or shorted wiring in the request circuit
3. Loose, corroded, or damaged connector
4. Fault in a related relay or control circuit

Symptoms

• Check-engine light on
• Engine may not crank when start is requested
• Intermittent or delayed cranking
• Start-stop or push-button starting may be unavailable

How to diagnose it

1. Check freeze-frame data and scan-tool start-request status while operating the start button or switch to determine whether the request reaches the module.
2. Inspect the starter request switch or button connector and accessible wiring for looseness, corrosion, or damage.
3. Check the related fuse and relay, then verify circuit power and ground against the wiring diagram and manufacturer's specification.
4. Test the request signal wire for an open or short and confirm the signal changes at the module when start is requested.
5. If the circuit checks out, test the switch or button and related control circuit using the manufacturer's procedure.

Common fixes

• Secure or clean a loose or corroded starter request connector.
• Repair damaged or open wiring in the request circuit.
• Replace a failed fuse or relay after checking for the cause of failure.
• Replace a faulty starter request switch or button if its signal fails testing.

Can I keep driving?

If the engine starts and runs normally, driving is generally unaffected, but the vehicle may fail to restart after you switch it off. Avoid shutting the engine down somewhere a no-start would leave you exposed or stranded.