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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 Grand Am 🢒 Engine 🢒 Engine Electrical 🢒 Electronic Ignition (EI) System Diagnosis

Circuit Description

The ignition control module (ICM) has independent power and ground circuits. The circuits between the ICM and the powertrain control module (PCM) consist of the following circuits:

    • The ignition control (IC) timing signal
    • The IC timing control
    • The low-resolution engine speed signal
    • A low reference

For a complete system description, refer to Electronic Ignition (EI) System Description .

Step

Action

Values

Yes

No

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Inspect the fuse that supplies power on the ignition 1 voltage circuit to the ignition control module (ICM).

Is the fuse open?

--

Go to Step 17

Go to Step 3

3

Test for an intermittent and for a poor connection at the power and ground 2-way connector of the ICM. 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 24

Go to Step 4

4
  1. Disconnect the power and ground 2-way connector from the ICM.
  2. Probe the ignition 1 voltage circuit with a test lamp that is connected to the ground circuit, at the 2-way connector.

    3. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 5

5

Probe the ignition 1 voltage circuit at the 2-way connector, with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 19

Go to Step 18

6
  1. Disconnect the crankshaft position (CKP) sensor A.
  2. Observe the 3X crank sensor parameter with a scan tool.
  3. Crank the engine.

Does the scan tool indicate a 3X crank sensor signal present?

--

Go to Step 7

Go to Crankshaft Position Sensor System Diagnosis

7
  1. Remove the fuel pump relay with the J 43244 Relay Puller Pliers.
  2. Connect the CKP sensor A.
  3. Test for spark at each cylinder with a J 26792 Spark Tester.

Did you have spark on any of the cylinders?

--

Go to Step 8

Go to Step 16

8

Did you have spark on all of the cylinders?

 

Go to Step 9

Go to Step 11

9

Does the spark tester indicate a bright blue spark on all cylinders?

--

Go to Step 10

Go to Step 11

10
  1. Remove the spark plugs.
  2. Examine the spark plugs for any abnormal conditions or damage. Refer to Spark Plug Inspection .

Are the spark plugs in good condition?

--

System OK

Go to Step 20

11
  1. Turn OFF the ignition.
  2. Connect the J 26792 to the spark plug wire of the inoperative cylinder.
  3. Switch the inoperative spark plug wire connection with a known good cylinder at the ignition coils.
  4. Crank the engine.

Do you have spark on the inoperative cylinder?

--

Go to Step 12

Go to Step 14

12
  1. Disconnect the spark plug wires from the inoperative ignition coil.
  2. Measure the secondary resistance of the ignition coil.

Is the resistance within the specified range?

5,000-8,000 ohms

Go to Step 13

Go to Step 22

13
  1. Remove the inoperative ignition coil.
  2. Connect a test lamp between the control circuits of the ignition coil on the ICM.
  3. Crank the engine.

Does the test lamp flash while the engine is being cranked?

--

Go to Step 15

Go to Step 23

14

Test the spark plug wires for the following conditions:

    • Proper routing and correct firing order--Refer to Ignition System Specifications .
    • Arching to ground

       Important: If carbon tracking or corrosion is detected, replace both components that are affected.

    • Carbon tracking or corrosion

Did you find and correct the condition?

--

Go to Step 24

Go to Step 21

15

Test for an intermittent and for a poor connection at the ignition coil. 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 24

Go to Step 22

16

Test for an intermittent and for a poor connection at the ICM. 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 24

Go to Step 23

17

Test the ignition 1 voltage circuit of the ICM for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 24

Go to Step 23

18

Repair the open in the ignition 1 voltage circuit of the ICM. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 24

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19

Repair the open in the ground circuit of the ICM. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 24

--

20

Replace the spark plugs. Refer to Spark Plug Replacement .

Did you complete the replacement?

--

Go to Step 24

--

21

Replace the spark plug wires. Refer to Spark Plug Wire Replacement .

Did you complete the replacement?

--

Go to Step 24

--

22

Replace the ignition coil. Refer to Ignition Coil Replacement .

Did you complete the replacement?

--

Go to Step 24

--

23

Replace the ICM. Refer to Ignition Control Module Replacement .

Did you complete the replacement?

--

Go to Step 24

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24
  1. Reassemble the vehicle as necessary.
  2. Turn the ignition OFF for 30 seconds.
  3. Start the engine and operate the vehicle.
  4. Observe the vehicle performance and driveability.

Does the vehicle operate normally?

--

System OK

Go to Step 1