P0615
Starter Relay Circuit
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The P0615 code indicates that the Powertrain Control Module (PCM) has detected an abnormal voltage reading in the starter relay circuit. This circuit is responsible for sending electrical power from the battery to the starter motor when you turn the key or press the start button. The PCM monitors this circuit to ensure the starter engages properly and only when the vehicle is in the correct gear position.
In many cases, this code may not affect normal driving once the engine is running, since the starter circuit is only active during engine cranking. However, you may experience intermittent no-start conditions, slow cranking, or clicking noises when trying to start the vehicle. A more concerning symptom is if the code indicates the starter can engage when the transmission is not in Park or Neutral, which is a safety issue.
The most common fix is replacing the starter relay, which is often an inexpensive, plug-in component located in the under-hood fuse box. This is a reasonable DIY repair for most car owners. If the relay tests fine, inspect the wiring between the ignition switch, neutral safety switch, relay, and starter for corrosion or damage. A failing starter motor itself can also trigger this code and typically needs a mechanic to replace.
Severity
Symptoms
- •Engine cranks slowly or does not crank at all
- •Intermittent no-start conditions — sometimes starts, sometimes doesn't
- •Clicking noise from the relay or starter area when turning the key
- •Check engine light illuminated
- •Vehicle may start in gear positions other than Park or Neutral (safety concern)
Likely Causes
The starter relay is a small electromechanical switch that routes high-amperage power to the starter motor. Internal contacts wear out over time, causing intermittent or complete failure to engage the starter.
Wiring between the PCM, ignition switch, neutral safety switch, and starter relay can develop corrosion, chafing, or breaks that prevent proper voltage from reaching the relay.
A worn starter motor or its integrated solenoid can draw excessive current or fail to engage, causing the PCM to detect abnormal voltage readings in the starter relay circuit.
The ignition switch sends the start signal through the neutral safety switch to the relay circuit. Failure of either component can cause voltage readings outside normal parameters.
In rare cases, the PCM itself may have an internal fault in the circuit that monitors or controls the starter relay, causing a false code.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace the starter relay (often a simple plug-in relay in the fuse box)
- Inspect and repair corroded or damaged wiring and connectors in the starter circuit
- Replace the starter motor and/or solenoid if faulty
- Replace the ignition switch if it fails testing
- Replace the neutral safety switch if it's not functioning properly