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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Yukon XL - 4WD 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Starter Solenoid Does Not Click

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.

Circuit/System Description

The engine control module (ECM) controls engine cranking based on a power mode input and the status of the park/neutral position (PNP) switch.

With the transmission in Park/Neutral, voltage at the park/neutral signal circuit is low. This indicates to the ECM that conditions are acceptable for cranking. When a power mode crank request is seen, the ECM applies B+ to the relay coil control circuit. This energizes the coil side of the STRTR relay, which pulls the switch side of the relay closed, applying voltage to the starter and engaging the starter solenoid.

Reference Information

Schematic Reference

Starting and Charging Schematics

Connector End View Reference

Engine Electrical Connector End Views

Description and Operation

Starting System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification
  1. Ignition ON, verify the PNP switch is properly adjusted. Refer to Park/Neutral Position Switch Adjustment for 4L80/85-E transmission.
  2. Transmission range selector in park or neutral, verify the scan tool ECM PNP Switch parameter displays Park/Neutral.
    3. ⇒If not the specified value, refer to PNP Switch Circuit Malfunction.
  3. Transmission range selector in park or neutral, attempt to start the vehicle. The starter relay should click and the engine should begin cranking.
    4. ⇒If the STRTR relay does not click or the engine does not crank, refer to Starter Relay Circuit Malfunction.

Circuit/System Testing

PNP Switch Circuit Malfunction (4L60/65/70/80/85-E)

  1. Ignition OFF, disconnect the harness connector at the PNP switch.
  2. Test for less then 1 ohm of resistance between the ground circuit terminal 7 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool verify the scan tool ECM PNP Switch parameter displays In Gear.
    4. ⇒If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the ECM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 7. Verify the scan tool ECM PNP Switch parameter displays Park/Neutral.
    5. ⇒If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, test or replace the PNP switch.

PNP Switch Circuit Malfunction (6L50/80/90-E)

  1. Ignition OFF, disconnect the harness connector at the AT Inline 20-Way Connector.
  2. Ignition ON, verify the scan tool verify the scan tool ECM PNP Switch parameter displays In Gear.
    3. ⇒If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the ECM.
  3. Install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool ECM PNP Switch parameter displays Park/Neutral.
    4. ⇒If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  4. If all circuits test normal, test or replace the internal mode switch (IMS).

Starter Relay Circuit Malfunction

  1. Ignition OFF, disconnect the starter relay.
  2. Test for less than 1 ohm of resistance between the relay coil ground circuit terminal and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify a test lamp illuminates between the relay switch B+ circuit terminal and ground.
    4. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  4. Momentarily install a 40A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit. The starter solenoid should engage and the engine should begin cranking.
    5. ⇒If the solenoid does not engage, test the relay controlled output circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the starter motor.
  5. Connect a test lamp between the relay coil control circuit terminal and the relay coil ground circuit terminal.
  6. 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.
    7. ⇒If the test lamp is always ON, test the control circuit for a 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.
  7. If all circuits test normal, test or replace the starter relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Park/Neutral Position Switch Replacement
    •  Park/Neutral Position Switch Replacement
    •  Manual Shift Shaft Position Switch Replacement
    •  Control Module References