OBD-II Code P0615 — What It Means & How to Fix It

What Does This Error Mean?

P0615 means there is a problem with the starter relay circuit. The starter relay is a switch that the engine computer uses to send power to the starter motor when you turn the key or press the start button. When this circuit fails, the engine may not crank at all, or may crank only intermittently. This code does not always mean the starter itself is bad — the relay or its wiring may be the issue. Diagnosis involves checking the relay, its fuse, and the wiring from the ECM to the relay.

Affected Models

All vehicles 1996+
Common in Ford and Lincoln vehicles
Common in GM cars and trucks
Common in Chrysler, Dodge, and Jeep vehicles
Common in vehicles with push-button start systems

Common Causes

Faulty starter relay that has failed open or has burned contacts
Damaged or corroded wiring between the ECM and the starter relay
Blown fuse for the starter relay circuit
Corroded or loose starter relay connector
Faulty engine control module output for the starter relay circuit

How to Fix It

Locate the starter relay in the fuse/relay box — usually under the hood. Check the relay fuse first. A blown fuse is a common cause and a very cheap fix.

Your owner's manual or fuse box lid should identify which relay is the starter relay.
Swap the starter relay with an identical relay from another circuit in the same fuse box to test. If the engine now cranks, the original relay was bad — replace it.

This swap test costs nothing and takes about 60 seconds.
Inspect the wiring at the starter relay connector. Look for burned, melted, or corroded terminals. Clean or repair as needed.

High current through the relay connector can cause heat damage over time, especially on older vehicles.
Test the control wire from the ECM to the relay. With a multimeter, verify that voltage appears on the control pin when the key is turned to Start. No voltage indicates an ECM output fault or broken wire.

The control wire carries a small signal voltage — typically 12V. The relay coil uses this to switch the high-current circuit.
If the relay and wiring are good but the code persists, have the ECM's starter relay output tested at a shop. An ECM output failure is rare but possible.

Before condemning the ECM, verify the wiring from the ECM to the relay is completely undamaged.

When to Call a Professional

Starter relay replacement is an easy and inexpensive DIY repair. Relays typically cost $10 to $25 and are sold at any auto parts store. If wiring is damaged, repair costs at a shop are $75 to $200 depending on complexity. If the starter itself has failed, starter replacement costs $150 to $400 for parts plus $100 to $200 labor. Always test the relay first before buying a starter.

Frequently Asked Questions

Will P0615 stop my car from starting?

Yes — this is the most common symptom. If the starter relay circuit has completely failed, the starter will not receive power and the engine will not crank. Sometimes the relay fails intermittently, so the car starts sometimes but not others.

Is the starter relay the same as the starter motor?

No — they are different parts. The starter motor is the large electric motor that physically cranks the engine. The starter relay is a smaller electrical switch that turns the starter motor on and off. The relay is much cheaper and easier to replace than the starter motor.

Can I replace the starter relay myself?

Yes, easily. Most starter relays simply pull out of the fuse box and push back in. You do not need any tools. Buy the exact same relay by matching the number printed on the relay body.