This is a generic diagnostic trouble code (DTC) and applies to many OBD-II vehicles (1996 and newer). This may include, but is not limited to, vehicles from Cadillac, Nissan, Chevy, Buick, Honda, Acura, Infiniti, Peugeot, Toyota, GMC, Chevrolet, Mazda, Ford, Subaru, etc. Although generic, the exact repair steps may vary depending on the year, make, model, and powertrain configuration.
Trouble code P0615 is associated with the starter relay circuit, and in most cases, the vehicle will not start. It is set when the Powertrain Control Module (PCM) detects a malfunction in the starter relay circuit, also referred to as the ignition switch circuit. Several codes can be set when the PCM detects incorrect signals in the starter relay circuit depending on the specific malfunction. The most common codes associated with this circuit are P0615, P0616, and P0617.
The purpose of the starter relay circuit is to provide a power source to the starter to crank the engine and start the vehicle. Depending on the specific vehicle and transmission configuration, several components are involved in this process. This circuit starts at the battery and includes the ignition switch, fuses, starter solenoid, starter relay, and various safety devices such as clutch position sensors and neutral safety switches.
Code P0615 is set by the PCM when it detects a general malfunction in the starter relay circuit.
Starter Relay in a Ford:
Starter Relay
How severe is this DTC?
The severity of this code can vary greatly from a simple illuminated check engine light on a vehicle that starts and runs, to an automobile that does not start at all.
What are some of the symptoms of the code?
Symptoms of a P0615 trouble code may include:
Engine does not crank
Sporadic no-crank events
Check Engine Light illuminated
What are some of the common causes of the code?
Causes
of this P0615 code may include:
Faulty ignition switch
Faulty starter relay
Faulty starter solenoid
Blown fuse or fusible link (if applicable)
Corroded or damaged connector
Corroded or damaged battery cable
Faulty or damaged wiring
Faulty PCM
Faulty starter
What are the P0615 troubleshooting steps?
The first step in the troubleshooting process for any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save a lot of time in the long run by pointing you in the right direction.
The second step is to consult the vehicle-specific technical data to see if a fuse is incorporated into the starter relay circuit and check if it is blown, if applicable. If the fuse is good, you need to locate all components associated with the starter relay circuit and check for obvious damage. Perform a thorough visual inspection to check that the associated wiring has no obvious defects such as scraping, rubbing, bare wires, or burn marks. Then, check the connectors and connections for security, corrosion, and damaged pins. This process should include all wiring connectors and connections to the battery, ignition switch, PCM, starter, starter relay, and starter solenoid.
Advanced Steps
Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and the vehicle-specific technical references. Voltage requirements will be highly based on the specific year and model of the vehicle.
Voltage Checks
Battery voltage should be appropriate at 12 volts, and the starter should have battery voltage with the ignition switch in the start position. The presence of voltage when the starter does not engage is an indication of a faulty starter or starter solenoid. A lack of voltage indicates a faulty ignition switch or a wiring problem.
If this process identifies a missing power source or ground, continuity tests may be required to check the integrity of the wiring, ignition switch, and other components. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings for wiring and connections should be 0 ohms of resistance, unless otherwise indicated by the technical data. Resistance or a lack of continuity is an indication of faulty wiring that is open or shorted and must be repaired or replaced.
What are the common repairs for this code?
Replacing the ignition switch
Replacing a blown fuse or fusible link (if applicable)
Cleaning corrosion from connectors
Repairing or replacing wiring
Repairing or replacing battery cables or terminals
Replacing the starter relay
Replacing the starter solenoid
Replacing the starter
Flashing or replacing the PCM
Common mistakes can include:
Replacing the starter or PCM when damaged wiring or another component is the issue.
I hope the information in this article has been helpful in pointing you in the right direction to fix the problem with your starter relay circuit error code. This article is strictly informational, and the technical data and service bulletins specific to your vehicle should always take priority.