GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 DTC 🢒 DTC P0615

Circuit Description

The engine control module (ECM) supplies a ground path for the starter relay when start enable has been requested. The ECM monitors this circuit for conditions that are incorrect for the commanded state. If the ECM detects an improper circuit condition, starter relay DTC P0615 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0615 Starter Relay Control Circuit

Conditions for Running the DTC

System voltage is between 9-16 volts.

Conditions for Setting the DTC
    • The ECM detects an improper voltage level on the output circuit that controls the starter relay.
    • The condition exists for at least 2 seconds.

Action Taken When the DTC Sets
    • The ECM will not illuminate the malfunction indicator lamp (MIL)
    • The ECM will store the conditions present when the DTC set as Failure Records data only.

Conditions for Clearing the MIL/DTC
    • The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
    • The DTC can be cleared by using the scan tool Clear DTC Information function.

Diagnostic Aids

Ignition system DTCs set with the ignition switch in the START position if the starter relay or the starter is inoperative. When the ECM enables starter operation, the ECM also initiates the diagnostic test routines for DTCs P0335, P0340, and P0385. If a condition exists which prevents the engine from cranking, the ECM will not receive signal input from the crankshaft position (CKP) and camshaft position (CMP) sensors, and the DTCs will set.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may assist in diagnosing the condition. The information may help determine how often the condition that set the DTC occurs.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Listen for an audible click when the starter relay operates. Press the ignition switch back and forth from the ON to START positions. Repeat this as necessary.

    2.

  2. This step tests for voltage at the coil side of the starter relay. The STARTER RLY fuse supplies power to the coil side of the starter relay.

    3.

  3. This step verifies that the ECM is providing ground to the starter relay.

    4.

  4. This step tests if ground is constantly being applied to the starter relay.

Step

Action

Yes

No

Schematic Reference: Starting and Charging Schematics

Connector End View Reference: Power and Grounding Connector End Views in Wiring Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Press the ignition back and forth from the ON to START positions.

Does the starter relay click with each command?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the starter relay.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the starter relay coil supply voltage circuit of the starter relay with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 8

4

  1. Connect a test lamp between the starter relay control circuit and the starter relay coil supply voltage circuit of the starter relay.
  2. Turn the ignition back and forth from the ON to START positions.

Does the test lamp turn ON and OFF with each command?

Go to Step 6

Go to Step 5

5

Test the control circuit of the starter relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Inspect for poor connections at the starter relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

7

Inspect for poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

Repair the battery positive voltage circuit of the starter relay. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 11

--

9

Replace the starter relay.

Did you complete the replacement?

Go to Step 11

--

10

Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

11
  1. Review and record the scan tool Failure Records data.
  2. Clear the DTCs.
  3. Operate the vehicle within the Failure Records conditions as noted.
  4. Using a scan tool, monitor the Specific DTC Information for DTC P0615.

Does the scan tool indicate DTC P0615 failed this ignition?

Go to Step 2

System OK