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Chevrolet Silverado / GMC Sierra. Manual - part 1695
1. Ignition On. Measure and record the voltage at the battery terminals. Verify that the battery
voltage is 11-15 volts. Repeat with the engine running.
If the battery voltage is not within the specified range, go to Charging System Test.
2. Engine running. Observe the scan tool Ignition 1 Signal parameter in the ECM data list.
Verify that the scan tool displays a value that is within 1 volt of the battery voltage recorded
in step 1.
If the scan tool parameter is not within the specified range, replace the ECM.
3. Go to Diagnostic Aids.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM replacement, setup, and programming
DTC P0615
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0615
Starter Relay Control Circuit
Diagnostic Fault Information
Circuit/System Description
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
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
STRTR Relay Control
P0615
P0615
P0615
-
Ground
-
P0615
-
-
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
then sends a message to the engine control module (ECM) that crank has been requested. The
ECM then verifies that the clutch is depressed for the manual transmission or that the automatic
transmission is in Park or Neutral. If it is, the ECM then supplies 12 volts to the control circuit of
the STRTR relay. When this occurs, battery voltage is supplied through the switch of the STRTR
relay to the S terminal of the starter solenoid. The ECM monitors the voltage on the STRTR relay
control circuit. If the ECM detects that the STRTR relay control circuit is open or shorted, then
DTC P0615 sets.
Conditions for Running the DTC
The Ignition is in the START position.
The system voltage is between 9.5-18 volts.
Conditions for Setting the DTC
The ECM detects improper voltage on the control circuit of the STRTR relay.
Action Taken When the DTC Sets
DTC P0615 is a C type DTC.
Conditions for Clearing the DTC
DTC P0615 is a C type DTC.
Diagnostic Aids
Verify that the ground connection for the STRTR relay ground circuit is clean and tight.
Inspect the terminals for the STRTR relay in the underhood fuse block for poor connections.
Reference Information
Schematic Reference
Starting and Charging Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Starting System Description and Operation
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON. Verify that no theft deterrent or automatic transmission DTCs are set that
would cause the ECM to disable engine starting.
If any DTCs are set that would cause the ECM to disable starting, then refer to
Diagnostic Trouble Code (DTC) List - Vehicle .
2. Clear the DTCs. Start the engine. Verify that DTC P0615 does not set.
Circuit/System Testing
1. Ignition OFF, test for less than 5 ohms between the relay ground circuit terminal 85 and
ground.
If greater than the specified range, test the ground circuit for an open/high resistance.
2. Ignition OFF. Connect a test lamp between the control circuit terminal 86 and the ground
circuit terminal 85. Turn the ignition to the start position. The test lamp should turn ON
when the ignition is in the START position, and OFF in all other positions.
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.
3. If all circuits test normal, test or replace the STRTR relay.
Component Testing
STRTR Relay
1. Ignition OFF, disconnect the STRTR relay.
2. Test for 60-180 ohms between terminals 85 and 86 of the relay.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
If not within the specified range, replace the STRTR 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 20 amp fused jumper wire between relay terminal 85 and 12 volts. Install a jumper
wire between relay terminal 86 and ground. Test for less than 2.0 ohms between terminals
30 and 87 of the relay.
If greater than specified range, replace the relay.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Relay Replacement (Attached to Wire Harness) or Relay Replacement (Within an
Electrical Center)
Control Module References for ECM replacement, setup, and programming
DTC P0621
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P0621
Generator L-Terminal Circuit
Diagnostic Fault Information
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Generator Turn On Signal
P0621
P0621
P0621
-
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Electrical - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado
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