Starter Relay Circuit
Diagnostic trouble code P0615 indicates a malfunction in the starter relay circuit. The Powertrain Control Module (PCM) sets this code when it detects an improper voltage or resistance level in the starter relay control circuit, preventing normal starter operation.
This code is considered high severity because it directly affects the vehicle's ability to start. If left unresolved, it can leave you stranded.
Common symptoms
- Engine cranks but will not start
- Engine does not crank at all (no-start condition)
- Intermittent starting issues
- Clicking sound when turning the key or pressing the start button
- Illuminated Check Engine Light
Likely causes
- Faulty starter relay
- Blown fuse or fusible link in the starter circuit
- Corroded, loose, or damaged wiring in the starter relay circuit
- Faulty ignition switch
- Defective starter motor or solenoid
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Check the starter relay fuse and swap the starter relay with a known good identical relay.
Look for: If the fuse is blown, replace it and retest. If swapping the relay allows the vehicle to start normally, the original relay is faulty.
Inspect the wiring and connectors in the starter relay circuit for visible damage or corrosion.
Look for: Look for frayed wires, melted insulation, or corroded pins that could cause high resistance or an open circuit.
Test for battery voltage at the starter relay control terminal while an assistant turns the ignition to the START position.
Look for: You should see near battery voltage (usually around 12V) when the key is turned. If voltage is missing, the issue is likely upstream (e.g., ignition switch or wiring).
Check the ground circuit for the starter relay.
Look for: Use a multimeter to verify continuity to ground. High resistance or an open ground will prevent the relay from energizing.
Test the starter motor and solenoid directly by bypassing the relay (using a fused jumper wire).
Look for: If the starter engages and cranks the engine when bypassed, the starter itself is good, confirming the issue is in the control circuit or relay.
This page explains the generic P0615 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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