Schematic Reference: Starting and Charging Schematics

Did you preform the Engine Electrical Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Engine Electrical

Turn the ignition switch to the START position.

Does the engine crank?

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

Go to Step 3

Turn the ignition switch to the START position.

Does the starter motor relay click?

Go to Step 11

Go to Step 4

1. Turn OFF the ignition.
2. Disconnect the powertrain control module (PCM) harness connector.
3. Connect a test lamp between the Crank Voltage circuit of the PCM harness and a good ground.
4. With the transmission in park, turn the ignition switch to the START position.

Does the test light illuminate?

Go to Step 7

Go to Step 5

Inspect for poor connections at the PCM connector, Underhood Fuse Block or ignition switch harness connector. 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 29

Go to Step 6

Test the supply voltage circuit of the crank voltage circuit and Crank fuse for an open or high resistance. 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 29

Go to Step 27

1. Turn OFF the ignition.
2. Disconnect the PCM harness connector.
3. Connect a test lamp between the starter enable relay control circuit of the PCM harness and a good ground.
4. Turn the ignition to the START position.

Does the test lamp illuminate?

Go to Step 19

Go to Step 8

1. Remove the starter motor relay.
2. Connect a test light from the supply voltage circuit of the starter motor relay coil circuit to ground.
3. With the transmission in park, turn the ignition switch to the START position.

Does the test light illuminate?

Go to Step 9

Go to Step 10

1. Connect a test light from the supply voltage circuit of the starter motor relay coil circuit to the control circuit of the starter motor relay coil circuit.
2. With the transmission in park, turn the ignition switch to the START position.

Does the test light illuminate?

Go to Step 17

Go to Step 14

1. Turn OFF the ignition.
2. Disconnect the park neutral position (PNP) switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transmission - 4L60-E/4L65-E.
3. Turn ON the ignition, with the engine OFF.
4. Connect a 10-amp fused jumper between the starter motor relay coil control circuits of the PNP switch.
5. With the transmission in PARK, turn the ignition switch to the START position.

Does the test lamp illuminate?

Go to Step 18

Go to Step 15

1. Turn OFF the ignition.
2. Disconnect the starter motor relay.
3. Connect a test lamp between the battery positive voltage circuit of the starter motor relay switch circuit and a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 23

Connect a 30-amp fused jumper between the battery positive voltage circuit of the starter motor relay switch circuit and the supply voltage circuit of the starter solenoid.

Does the engine crank?

Go to Step 17

Go to Step 13

Does the fuse in the jumper open?

Go to Step 24

Go to Step 16

Test the control circuit of the starter motor relay for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 25

Test the supply voltage circuit of the starter motor relay coil circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 21

Test the supply voltage circuit of the starter solenoid for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 22

Inspect for poor connections at the starter motor 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 29

Go to Step 25

If equipped with an automatic transmission, inspect for poor connection at the PNP switch harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. If OK, perform the Park/Neutral Position Switch Adjustment in Automatic Transmission - 4L60-E/4L65-E.

Did you find and correct the condition?

Go to Step 29

Go to Step 26

Inspect for poor connections at the harness connector of the PCM. 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 29

Go to Step 20

Important: The replacement PCM must be programmed.

Replace the PCM/engine control module (ECM). Refer to Powertrain Control Module Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L, Powertrain Control Module Replacement in Engine Controls - 8.1L.

Is action complete?

Go to Step 29

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Inspect for poor connections at the ignition switch harness connector. 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 29

Go to Step 27

Inspect for poor connections at the starter solenoid. 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 29

Go to Step 28

Repair the open or high resistance in the battery positive voltage circuit of the Starter Motor relay switch circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

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Repair the short to ground in the supply voltage circuit of the starter solenoid. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

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Replace the Starter Relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 29

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Replace the PNP switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transmission - 4L60-E/4L65-E.

Did you complete the replacement?

Go to Step 29

--

Replace the ignition switch. Refer to Ignition and Start Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 29

--

Replace the starter. Refer to Starter Motor Replacement .

Did you complete the replacement?

Go to Step 29

--

Operate the system for which the symptom occurred.

Did you correct the condition?

System OK

Go to Step 2