P0615: Starter Relay Circuit Malfunction

What P0615 tells you, and what it does not

The computer controls the starter relay on many vehicles, and this code means it is not seeing the electrical behavior it expects from that relay circuit.

The code sits in the starter relay circuit area and is reported by the comprehensive component monitor. It names the circuit or the condition where the computer saw a reading outside its expected range. It does not name a failed part, and several genuinely different faults set this same code, which is the whole reason the causes below are ordered rather than listed.

What people usually notice

• No crank on some attempts
• Starter stays engaged after the engine starts
• Clicking from the starter relay
• Intermittent no-start

What causes P0615?

The causes below are ordered by how often they turn out to be the answer, cheapest and most common first. That order matters more than the list itself: the expensive component named in the code text is very rarely the first thing to replace, and working down from the top is what stops a starter relay circuit fault becoming an expensive guess.

Corroded relay socket or connector is the one to rule out before anything else. The most common and cheapest cause to check first.

Working out which cause it is

Start with freeze frame. There is no engine freeze frame for a starting circuit code, check the stored starter relay command state instead. That snapshot is taken at the instant the code set, and it is the single most useful piece of evidence you have, which is also why clearing the code before reading it is such a costly habit.

Diagnosing this one properly means commanding a component and watching whether it responds, which a read-only tool cannot do at any price. Bidirectional control lets you command the starter relay circuit directly to confirm whether the relay or the wiring is at fault.

The order worth working in

• 1. Corroded relay socket or connector: The most common and cheapest cause to check first.
• 2. Blown fuse: A lost supply voltage prevents the relay from being commanded at all.
• 3. Sticking or failed relay: The relay contacts wear out over time and can stick.
• 4. Wiring fault between the computer and relay: A break or short in this wiring prevents proper relay control.
• 5. Worn starter motor drawing excess current: A failing starter can overload the relay and cause it to fail.

What P0615 means for driving the car

This affects starting the vehicle, not driving it once it is running, but an intermittent fault could leave you unable to restart if you turn the engine off.

This is a severity 2 of 4 code. It will not usually strand you, but it will fail an emissions test while it is present, and the underlying fault rarely gets cheaper by being left alone.

What does it cost to ignore P0615?

An intermittent starting fault tends to become a full no-start, potentially stranding you unexpectedly.

There is also the diagnostic cost of waiting. Freeze frame data, pending code history and the readiness monitor state all describe the fault as it was when it set, and all of it is lost the moment somebody clears the code to make the lamp go out.