Schematic Reference: Starting and Charging Schematics

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

Did you perform the Vehicle Diagnostic System Check?

Go to Step 2

Go to Diagnostic Starting Point - Computer/Integrating Systems in Computer/Integrating Systems

Apply the brake and press the Start button.

Does the engine crank?

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

Go to Step 3

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the Crank Request parameter in the PCM data list.
4. Apply the brake and press the Start button.

Does the scan tool display Yes?

Go to Step 5

Go to Step 4

1. Turn ON the ignition, with the engine OFF.
2. Verify that the transmission is in Park or Neutral.
3. With a scan tool, observe the IMS parameter in the TCM data list.

Does the scan tool display Park or Neutral?

Go to Step 13

Go to in Automatic Transaxle- 5L50- E

Apply the brake and press the Start button.

Do you hear the Crank relay click?

Go to Step 8

Go to Step 6

1. Turn OFF the ignition.
2. Disconnect the Crank relay.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the battery positive voltage circuit of the Crank relay coil and a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 18

1. Connect a test lamp between the battery positive voltage circuit of the Crank relay coil and the control circuit of the Crank relay.
2. Apply the brake and press the Start button.

Does the test lamp illuminate?

Go to Step 14

Go to Step 12

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

Does the test lamp illuminate?

Go to Step 9

Go to Step 19

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

Does the engine crank?

Go to Step 14

Go to Step 10

Does the fuse in the jumper open?

Go to Step 20

Go to Step 11

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

Did you find and correct the condition?

Go to Step 25

Go to Step 15

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

Did you find and correct the condition?

Go to Step 25

Go to Step 17

Test the crank request input circuit of the PCM for a high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 25

Go to Step 16

Inspect for poor connections at the Crank 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 25

Go to Step 21

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 25

Go to Step 22

Inspect for poor connections at the ignition switch. 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 25

Go to Step 23

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 25

Go to Step 24

Repair an open or high resistance in the battery positive voltage circuit of the Crank relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 25

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

Did you complete the repair?

Go to Step 25

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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 25

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Replace the Crank relay.

Did you complete the replacement?

Go to Step 25

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Replace the Starter Motor. Refer to Starter Motor Replacement .

Did you complete the replacement?

Go to Step 25

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Replace the ignition switch. Refer to Ignition and Start Switch Replacement in Instrument Panel, Gages and Console.

Did you complete the replacement?

Go to Step 25

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Important: The replacement ECM must be programmed.

Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls-4.6L (LH2).

Did you complete the replacement?

Go to Step 25

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2