GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

SCHEMATIC REFERENCE: Starting and Charging Schematics

1

Did you perform the Diagnostic System Check for starting and charging?

Go to Step 2

Go to Diagnostic System Check - Engine Electrical .

2

Turn the ignition to the START position.

Does the engine crank?

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

Go to Step 3

3

  1. Install a scan tool.
  2. With a scan tool, observe the Crank Request parameter in the PCM data list.
  3. Turn the ignition switch to the START position.

Does the scan tool display Yes?

Go to Step 5

Go to Step 4

4

  1. With a scan tool, observe the Crank parameter in the IPC data list.
  2. Turn the ignition switch to the START position.

Does the scan tool display Yes?

Go to Step 12

Go to Step 13

5

Turn the ignition to the START position.

Does the CRANK relay click?

Go to Step 8

Go to Step 6

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 14

7

  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. Turn the ignition to the START position.

Does the test lamp illuminate?

Go to Step 18

Go to Step 15

8

  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 22

9

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

Does the engine crank?

Go to Step 18

Go to Step 10

10

  1. Disconnect the park neutral position (PNP) switch.
  2. Connect a 30 amp fused jumper between the starter solenoid supply voltage circuits of the PNP switch harness connector.

Does the engine crank?

Go to Step 17

Go to Step 11

11

Does the fuse in either jumper open?

Go to Step 23

Go to Step 16

12

Test the crank request signal circuit of the PCM 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 19

13

Test the crank signal circuit of the IPC 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 20

14

Test the battery positive voltage circuit of the CRANK relay coil 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 20

15

Test the control circuit of the CRANK relay for an open, high resistance 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 29

Go to Step 19

16

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 21

17

  1. Inspect the PNP switch for proper operation. Refer to Park/Neutral Position Switch Adjustment in Automatic Transaxle - 4T65 - E.
  2. 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.

Did you find and correct the condition?

Go to Step 29

Go to Step 24

18

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 29

Go to Step 25

19

Inspect for poor connection at the PCM 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 26

20

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

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 29

Go to Step 28

22

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 29

--

23

Repair the high resistance or 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

--

24

Replace the PNP switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transaxle - 4T65 - E.

Did you complete the replacement?

Go to Step 29

--

25

Replace the crank relay.

Did you complete the replacement?

Go to Step 29

--

26

IMPORTANT:: Perform the set up procedures for the PCM.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls - 2.5L (LB8) and 3.0L (L46).

Did you complete the replacement?

Go to Step 29

--

27

Replace the Ignition Switch. Refer to Ignition Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Did you complete the replacement?

Go to Step 29

--

28

Replace the Starter Motor. Refer to Starter Motor Replacement .

Did you complete the replacement?

Go to Step 29

--

29

Operate the system for which the symptom occurred.

Did you correct the condition?

System OK

Go to Step 2