Schematic Reference: Starting and Charging Schematics

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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 7

Go to Step 4

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, Neutral, or the clutch pedal depressed, turn the ignition switch to the START position.

Does the test light illuminate?

Go to Step 5

Go to Step 6

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, Neutral, or the clutch pedal depressed, turn the ignition switch to the START position.

Does the test light illuminate?

Go to Step 13

Go to Step 10

Is the starter equipped with over crank protection (OCP) thermal switch?

Go to Step 7

Go to Step 8

1. Turn OFF the ignition.
2. Disconnect the starter terminal switch.
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 starter terminal switch.
5. With the transmission in Park, Neutral, or the clutch pedal depressed, turn the ignition switch to the START position.

Does the test lamp illuminate?

Go to Step 18

Go to Step 8

1. Turn OFF the ignition.
2. Disconnect the park neutral position (PNP) switch. Refer to Park/Neutral Position and Backup Lamp Switch Replacement in Automatic Transmission - Allison for the neutral switch or Clutch Pedal Position Switch Replacement in Clutch for the clutch/starter interlock switch.
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, neutral switch, or clutch/starter interlock switch.
5. With the transmission in Park, Neutral, or the clutch pedal depressed, turn the ignition switch to the START position.

Does the test lamp illuminate?

Go to Step 16

Go to Step 13

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 10

Go to Step 19

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 15

Go to Step 11

Does the fuse in the jumper open?

Go to Step 20

Go to Step 14

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 25

Go to Step 21

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 25

Go to Step 17

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 25

Go to Step 18

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 25

Go to Step 21

Did you find and correct the condition?

Go to Step 25

Go to Step 22

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 25

Go to Step 23

Inspect for poor connections at the starter thermal switch/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 24

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 25

--

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

--

Replace the starter motor relay. Refer to Relay Replacement in Wiring Repairs.

Did you complete the replacement?

Go to Step 25

--

Replace the following switches:

Did you complete the replacement?

Go to Step 25

--

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

Did you complete the replacement?

Go to Step 25

--

Replace the starter. Refer to Starter Motor Replacement .

Did you complete the replacement?

Go to Step 25

--

Operate the system for which the symptom occurred.

Did you correct the condition?

System OK

Go to Step 2

Schematic Reference: Starting and Charging Schematics

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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 relay click?

Go to Step 9

Go to Step 4

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe one of the following.

•	With a manual transmission,observe the Clutch Pedal Switch parameter in the data list while fully depressing the clutch.

•	With a automatic transmission in PARK, observe the TR Sw parameter in the data list.

4. Turn the ignition to the START position.

Does the scan tool display Applied/Released on manual transmission or Park/Neutral on automatic transmission.

Go to Step 6

Go to Step 5

1. Turn OFF the ignition.
2. Disconnect the ECM/PCM harness connector.
3. Connect a test lamp between the Clutch Start Switch Signal or Park/Neutral signal of the ECM/PCM harness and a good ground.
4. With the transmission in Park, or clutch pedal depressed, turn the ignition switch to the START position

Does the test lamp illuminate?

Go to Step 17

Go to Step 8

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

Does the test light illuminate?

Go to Step 7

Go to Step 13

1. Connect a test light from the supply voltage circuit of the starter relay coil circuit to the control circuit of the starter relay coil circuit.
2. With the transmission in Park, or clutch pedal depressed, turn the ignition switch to the START position.

Does the test light illuminate?

Go to Step 9

Go to Step 12

1. Turn OFF the ignition.
2. Disconnect the park neutral position (PNP) switch Park/Neutral Position and Backup Lamp Switch Replacement in Automatic Transmission - Allison or Clutch Pedal Position Switch Replacement in Manual Transmission.
3. Turn ON the ignition, with the engine OFF.
4. Connect a 10-amp fused jumper between the starter relay coil supply voltage circuit of the PNP switch or clutch pedal position switch.
5. With the transmission in Park, or clutch pedal depressed, turn the ignition switch to the START position.

Does the test lamp illuminate?

Go to Step 16

Go to Step 19

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

Does the test lamp illuminate?

Go to Step 10

Go to Step 21

Important: The engine may crank in this step. Ensure the parking brake is applied, the transmission is in PARK on a automatic transmission or NEUTRAL on a Manual transmission.

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 15

Go to Step 11

Does the fuse in the jumper open?

Go to Step 22

Go to Step 14

Test the control circuit of the starter 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 27

Go to Step 17

Test the supply voltage circuit of the starter 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 27

Go to Step 15

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 27

Go to Step 20

Inspect for poor connections at the starter 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 27

Go to Step 23

1. 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 and Backup Lamp Switch Adjustment in Automatic Transmission - Allison.
2. If equipped with a manual transmission, inspect for poor connection at the clutch pedal position 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 27

Go to Step 24

Inspect for poor connections at the harness connector of the ECM/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 27

Go to Step 18

Replace the ECM/PCM Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Is action complete?

Go to Step 27

--

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 27

Go to Step 25

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 27

Go to Step 26

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

Did you complete the repair?

Go to Step 27

--

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 27

--

Replace the starter relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 27

--

1. Replace the PNP switch. Refer to Park/Neutral Position and Backup Lamp Switch Adjustment in Automatic Transmission - Allison.
2. Replace the clutch pedal position switch. Refer to Clutch Pedal Engine Start Switch Replacement in Clutch.

Did you complete the replacement?

Go to Step 27

--

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

Did you complete the replacement?

Go to Step 27

--

Replace the starter. Refer to Starter Motor Replacement .

Did you complete the replacement?

Go to Step 27

--

Operate the system for which the symptom occurred.

Did you correct the condition?

System OK

Go to Step 2