When the ignition switch is placed in the START position, a discrete signal is supplied to the body control module (BCM) notifying it that the ignition is in the START position. The BCM then sends a serial data message to the engine control module (ECM) that crank has been requested. The ECM then verifies that the transmission is in Park or Neutral. If it is, the ECM then supplies 12 volts to the control circuit of the START relay. When this occurs, battery voltage is supplied through the switch of the START relay to terminal A of the starter solenoid. The ECM monitors the voltage on the START relay control circuit. If the voltage is not what is expected, then DTC P0615 sets.

The system voltage is between 9.5-18 volts.

The ECM detects that the control circuit of the START relay is open, shorted to ground, or shorted to voltage for 2 seconds.

DTC P0615 is a type C DTC.

The condition for setting the DTC no longer exists for 2 seconds.

Inspect ground connection G109. Verify that it is clean and tight.

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Starting System Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition OFF, disconnect the START relay.
2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 30 seconds. Test for less than 5 ohms between the ground circuit terminal 85 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition OFF, connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 85.
4. With the transmission range selector in park or neutral, cycle the ignition key between the OFF and CRANK position. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for short to voltage. If the circuit tests normal, replace the ECM.

⇒	If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the START relay.

START Relay

1. Ignition OFF, disconnect the START relay.
2. Test for 60-180 ohms between terminals 85 and 86.

⇒	If not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the relay.

4. Install a 20A fused jumper wire between relay terminal 86 and 12 volts. Install a jumper wire between relay terminal 85 and ground. Test for less than 2.0 ohms between terminals 30 and 87.

⇒	If greater than specified range, replace the START relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.