2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2190

2010 Cadillac Truck Escalade/ESV RWD V8-6.2L Page 2190

1. Ignition ON. Verify that no immobilizer or automatic transmission DTCs are set that would cause the ECM to disable engine starting.

瀚慖f any DTCs are set that would cause the ECM to disable starting, then refer to Diagnostic Trouble Code (DTC) List - Vehicle (See:

Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle).

2. Attempt to start the engine. The engine should crank.

Circuit/System Testing

1. Ignition OFF, disconnect the STRTR relay.

2. Ignition OFF and scan tool disconnected, open and close the driver door, and wait 1 minute. Test for less than 5 Ohms between the relay

ground circuit terminal 85 and ground.

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

3. 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 for no longer than 10 seconds when the ignition is in the START position, and OFF in all other positions.

瀚慖f the test lamp is always on, test the control circuit for short to voltage. If the circuit tests normal, replace the ECM.

瀚慖f 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.

4. If all circuits test normal, test or replace the STRTR relay.

Component Testing

Relay Test

1. Ignition OFF, disconnect the STRTR relay.

2. Test for 60-180 Ohms between terminals 85 and 86.

瀚慖f 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

瀚慖f not the specified value, replace the relay.

4. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for

less than 2 Ohms between terminals 30 and 87.

瀚慖f greater than specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

* Relay Replacement (Attached to Wire Harness) (See: Power and Ground Distribution/Power Distribution Relay/Service and Repair/Relay

Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (See: Power and Ground Distribution/Power

Distribution Relay/Service and Repair/Relay Replacement (Within an Electrical Center))

* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming.

P0621

DTC P0621

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System

Check - Vehicle) prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an

overview of the diagnostic approach.

* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure

Instructions) provides an overview of each diagnostic category.