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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2002 🢒 Firebird 🢒 Engine 🢒 Engine Controls - 5.7L 🢒 Electronic Ignition (EI) System Diagnosis

Circuit Description

The electronic ignition system uses an individual ignition coil for each cylinder. The powertrain control module (PCM) controls the ignition operation through eight individual ignition control (IC) circuits. Each bank of four ignition coils is connected to the PCM, power, or ground by the following circuits:

    • Low reference
    • Chassis ground
    • Ignition 1 voltage
    • The appropriate IC circuit

The PCM triggers an ignition coil by grounding the appropriate IC circuit using information from the crankshaft position (CKP) and camshaft position (CMP) sensors.

Diagnostic Aids

Important: 

   • Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
   • For any test that requires probing the PCM or component harness connectors, use the Connector Test Adapter Kit . Using this kit prevents any damage to the harness connector terminals. Refer to in Wiring Systems.

Using Freeze Frame/Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the condition, the information included in the Freeze Frame/Failure Records data can help determine how many miles since the condition occurred. Operate vehicle within the same freeze frame conditions, including the RPM, the load, the vehicle speed, and the temperature that you observed. This will isolate when the condition occurred.

For an intermittent condition, refer to Intermittent Conditions .

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Monitoring the Misfire Current Counters determines if a fault is present.

    2.

  2. A good indication that the fuse is open is more than 2 of the Misfire Current Counters incrementing on one side of the engine. Inspect the ignition 1 voltage circuit for a grounded circuit.

    3.

  3. If the fuse is open and no condition can be found with the ignition coil/module circuits, inspect the injector circuits for being grounded.

Step

Action

Yes

No

Schematic Reference: Engine Controls Schematics

1

Did you perform the Diagnostic System Check-Engine Controls?

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2

Are DTCs P0200, P0300, P0335, P0336, P0351-P0358 set?

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

  1. Install a scan tool.
  2. Idle the engine.
  3. Using a scan tool, monitor all the Misfire Current counters on the misfire data list. There are 8 counters, one counter per cylinder.

Do any of the Misfire Current counters increment?

Go to Step 4

Go to Intermittent Conditions

4

Do the Misfire Current Counters increment for 2 or more cylinders on one bank of the engine?

Go to Step 8

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the ignition coil electrical harness connector that corresponds to the Misfire Current Counters that were incrementing.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the ignition voltage 1 circuit at the ignition coil electrical connector using the test lamp connected to battery ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp illuminate?

Go to Step 6

Go to Step 10

6

Using the test lamp probe the ignition 1 voltage circuit at the ignition coil or electrical connector to the ignition coil ground circuit.

Does the test lamp illuminate?

Go to Step 7

Go to Step 13

7

Using the test lamp probe the ignition 1 voltage circuit at the ignition coil electrical connector to the ignition coil low reference circuit.

Does the test lamp illuminate?

Go to Step 21

Go to Step 17

8

  1. Inspect for an open ignition coil fuse.
  2. Locate and repair the ignition 1 voltage circuit for grounded circuit if the fuse is open. Refer to Wiring Repairs in Wiring Systems.
  3. Replace the fuse.

Did you find and correct the condition?

Go to Step 23

Go to Step 9

9

Repair the open in the ignition 1 voltage circuit between the fuse block and the splice. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

10
  1. Disconnect the main ignition coil 8-way connector.
  2. Probe the ignition 1 voltage circuit at the ignition coil main 8-way connector using the test lamp connected to battery ground on the fuse side of the harness. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp illuminate?

Go to Step 11

Go to Step 12

11

Repair the open circuit between the main 8-way harness connector and the ignition coil connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

12

Repair the open ignition 1 voltage circuit between the fuse block and the main ignition coil 8-way harness connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

13
  1. Disconnect the main ignition coil 8-way connector.
  2. Using the test lamp probe the ignition 1 voltage circuit to the ignition coil ground circuit at the ignition coil/module main electrical 8-way connector. Refer to Troubleshooting with a Test Lamp in Wiring Systems.

Does the test lamp illuminate?

Go to Step 14

Go to Step 16

14
  1. Inspect for a poor connection at the main ignition coil electrical 8-way connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. Repair poor connections as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 15

15

Repair the open ground circuit between the main 8-way connector and the ignition coil connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

16

Repair the open ground circuit between ground and the main 8-way connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

17
  1. Disconnect the main ignition coil 8-way connector.
  2. Using the test lamp probe the ignition 1 voltage circuit at the ignition coil main electrical 8-way connector to the ignition coil low reference circuit.

Does the test lamp illuminate?

Go to Step 18

Go to Step 20

18
  1. Inspect for a poor connection at the main ignition coil electrical 8-way connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. If a poor connection is found, repair the connection as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 19

19

Repair the open low reference circuit between the main 8-way connector and the ignition coil connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

20

Repair the open low reference circuit between the PCM and the splice. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

21
  1. Inspect for poor connections at the ignition coil harness connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
  2. Repair poor connections as necessary. Refer to Repairing Connector Terminals in Wiring Systems.

Did you find and correct the condition?

Go to Step 23

Go to Step 22

22

Replace ignition coil. Refer to Ignition Coil Replacement .

Did you complete the replacement?

Go to Step 23

--

23
  1. Remove all test equipment except the scan tool.
  2. Connect any disconnected components.
  3. Turn OFF ignition for 30 seconds.
  4. Start engine and operate vehicle.
  5. Observe MIL, vehicle performance, and driveability.

Does the vehicle operate normally with no MIL illumination and no stored DTCs?

System OK

Go to Diagnostic Trouble Code (DTC) List