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Makes 🢒 Oldsmobile 🢒 2003 🢒 Alero 🢒 Engine 🢒 Engine Controls - 2.2L (L61) 🢒 Electronic Ignition (EI) System Diagnosis

Electronic Ignition (EI) System Diagnosis without Special Tool

Circuit Description

Each ignition coil supplies secondary voltage to a pair of spark plugs. This is called a waste spark ignition system. The powertrain control module (PCM) supplies ignition control (IC) signals to the ignition control module (ICM). The ICM fires the correct ignition coil at the correct time based on the IC signals. The ICM detects if cylinder 1 or cylinder 3 is on the compression stroke by sensing the secondary voltage and polarity of each side of the ignition coil. The ICM detects this voltage with sensing circuitry integrated into each ignition coil. The higher voltage is on the compressing cylinder. The ICM provides a synthesized cam signal to the PCM based on these inputs. This is called compression sense ignition. The PCM uses the cam signals to synchronize fuel injection.

This system consists of the following circuits:

    • Ignition 1 voltage
    • Ground
    • Camshaft position (CMP) sensor signal
    • IC timing control--2/3
    • IC timing control--1/4

Diagnostic Aids
    • A small amount of resistance in the battery positive voltage circuit to the PCM may cause a no start. Test the battery positive voltage circuit for excessive resistance or corrosion. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
    • The PCM grounds will cause a no start only if none of them are making a good connection. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • If the crankshaft position (CKP) sensor is loose the sensor may cause an intermittent no start by moving away from the reluctor wheel.

Test Description

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

  1. This step tests for a short to voltage in the ignition circuit.

    2.

  2. This step tests for a short to voltage in the battery circuit.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Crank the engine.
  2. Observe the CKP Active Counter on the scan tool.

Does the CKP Active Counter increment?

--

Go to Step  6

Go to Step  3

3
  1. Disconnect the CKP harness connector.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a DMM to the battery ground and each of the CKP sensor circuits at the CKP sensor harness connector.

Does the voltage measure more than the specified value?

3 V

Go to Step  4

Go to Step 9

4

Test each CKP sensor circuit for a short to 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  5

5

  1. Turn OFF the ignition.
  2. Retest each CKP sensor circuit for a short to 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  23

6
  1. Turn OFF the ignition.
  2. Remove the fuel pump relay with the J 43244 Relay Puller Pliers.
  3. Remove the ignition coil housing assembly. Refer to Ignition Coil Housing Replacement .

    4. Important: Not grounding the ignition coil housing, may cause erratic spark.

  4. Install a jumper wire with clips on both ends from the top of the ignition control module to ground.
  5. Install the J 36012-A Ignition System Diagnostic Harness.
  6. Install a J 26792 Spark Tester on the #1 spark plug jumper wire.
  7. Ground the #4 (companion to #1) spark plug jumper wire.
  8. Crank the engine with the remaining spark plug jumper wires connected.
  9. Repeat the above steps by installing the spark tester on #4 and grounding #1. Do the same for #2 and #3 spark plug wires making sure the companion wire is grounded.

Does the spark tester spark on all cylinders?

--

Go to Step 7

Go to Step 11

7
  1. Turn OFF the ignition.
  2. Inspect for malfunctioning spark plugs. Refer to Spark Plug Inspection .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 8

8

Inspect for basic engine problems. Refer to Symptoms - Engine Mechanical in Engine Mechanical.

Did you find and correct any conditions?

--

Go to Step 25

Go to Diagnostic Aids

9
  1. Connect the harness connector to the CKP sensor.
  2. Disconnect the harness connector from the PCM.
  3. Measure the resistance between the CKP sensor circuits.

Is the resistance within the specified value?

500-900 ohms

Go to Step 24

Go to Step 10

10

Test the CKP signal circuit and the low CKP reference circuit for the following conditions:

    • An open
    • High resistance
    • Circuits shorted together

Did you find and correct the condition?

--

Go to Step 25

Go to Step 19

11
  1. Turn OFF the ignition.
  2. Remove the spark plug jumper wires.
  3. Remove the ICM from the ignition coil housing. Refer to Ignition Control Module Replacement .
  4. Confirm that the interconnect is connected to the ICM module.
  5. Turn ON the ignition, with the engine OFF.
  6. Measure the voltage between the primary ignition coil voltage circuit at the ICM interconnect and a good ground.

Does the voltage measure near the specified value?

B+

Go to Step 12

Go to Step 13

12
  1. Connect a test lamp between battery voltage and the control circuit for the affected ignition coil.
  2. Crank the engine.

Does the test lamp blink?

--

Go to Step 22

Go to Step 15

13
  1. Turn OFF the ignition.
  2. Disconnect the ICM connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Use a DMM in order to measure the ICM ignition 1 voltage circuit.

Does the voltage measure near the specified value?

12 V

Go to Step 21

Go to Step 14

14

Test the ICM ignition 1 voltage circuit for the following:

    • An open
    • A short to ground

Did you find and correct the condition?

--

Go to Step 25

--

15
  1. Turn OFF the ignition.
  2. Disconnect the ICM connector.
  3. Connect a DMM from the affected IC timing control circuit to ground, set the DMM to AC voltage.
  4. Crank the engine.

Does the voltage measure within the specified range?

0.5-2 V

Go to Step 17

Go to Step  16

16

Test the affected IC timing control circuit for the following:

    • An open
    • A short to ground
    • A short to voltage
    • A short between the timing control circuits

Did you find and correct the condition?

--

Go to Step 25

Go to Step  23

17
  1. Turn OFF the ignition.
  2. With a test lamp connected to battery positive voltage, probe the ICM ground circuit.

Does the test lamp illuminate?

--

Go to Step 21

Go to Step 18

18

Test the ICM ground circuit for the following:

    • An open
    • A short to voltage

Did you find and correct the condition?

--

Go to Step 25

--

19

Inspect for poor connections at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 20

20
  1. Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Perform the CKP variation learn procedure. Refer to Crankshaft Position System Variation Learn .

Did you complete the replacement?

--

Go to Step 25

--

21

Replace the ICM. Refer to Ignition Control Module Replacement .

Did you complete the replacement?

--

Go to Step 25

--

22

Replace the ignition coil housing. Refer to Ignition Coil Housing Replacement .

Did you complete the replacement?

--

Go to Step 25

--

23

Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 24

24

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 25

--

25

Attempt to start the engine.

Does the engine start and continue to run?

--

Go to Step 26

Go to Step 2

26
  1. Turn OFF the ignition for 30 seconds.
  2. Start the engine and operate the vehicle.
  3. Observe the MIL, vehicle performance, and driveability.

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

--

Go to Diagnostic Trouble Code (DTC) List

System OK

Electronic Ignition (EI) System Diagnosis with Special Tool

Circuit Description

Each ignition coil supplies secondary voltage to a pair of spark plugs. This is called a waste spark ignition system. The powertrain control module (PCM) supplies ignition control (IC) signals to the ignition control module (ICM). The ICM fires the correct ignition coil at the correct time based on the IC signals. The ICM detects if cylinder 1 or cylinder 3 is on the compression stroke by sensing the secondary voltage and polarity of each side of the ignition coil. The ICM detects this voltage with sensing circuitry integrated into each ignition coil. The higher voltage is on the compressing cylinder. the ICM provides a synthesized cam signal to the PCM based on these inputs. This is called compression sense ignition. The PCM uses the cam signals to synchronize fuel injection.

This system consists of the following circuits:

    • Ignition 1 voltage
    • Ground
    • Camshaft position (CMP) sensor signal
    • IC timing control--2/3
    • IC timing control--1/4

Diagnostic Aids
    • A small amount of resistance in the battery positive voltage circuit to the PCM may cause a no start. Test the battery positive voltage circuit for excessive resistance or corrosion. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
    • The PCM grounds will cause a no start only if none of them are making a good connection. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • If the crankshaft position (CKP) sensor is loose the sensor may cause an intermittent no start by moving away from the reluctor wheel.

Test Description

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

  1. This step tests for a short to voltage in the ignition circuit.

    2.

  2. This step tests for a short to voltage in the battery circuit.

Step

Action

Value(s)

Yes

No

Schematic Reference: Engine Controls Schematics

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

1

Did you perform the Diagnostic System Check-Engine Controls?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Crank the engine.
  2. Observe the CKP Active Counter on the scan tool.

Does the CKP Active Counter increment?

--

Go to Step  6

Go to Step  3

3
  1. Disconnect the CKP harness connector.
  2. Turn ON the ignition, with the engine OFF.
  3. Connect a DMM to the battery ground and each of the CKP sensor circuits at the CKP sensor harness connector.

Does the voltage measure more than the specified value?

3 V

Go to Step  4

Go to Step 9

4

Test each CKP sensor circuit for a short to 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  5

5

  1. Turn OFF the ignition.
  2. Retest each CKP sensor circuit for a short to 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  23

6
  1. Turn OFF the ignition.
  2. Remove the fuel pump relay with the J 43244 Relay Puller Pliers.
  3. Remove the ignition coil housing assembly. Refer to Ignition Coil Housing Replacement .

    4. Important: Not grounding the ignition coil housing, may cause erratic spark.

  4. Install a jumper wire with clips on both ends from the top of the ignition control module to ground.
  5. Install the J 36012-A Ignition System Diagnostic Harness.
  6. Install a J 26792 Spark Tester on the #1 spark plug jumper wire.
  7. Ground the #4 (companion to #1) spark plug jumper wire.
  8. Crank the engine with the remaining spark plug jumper wires connected.
  9. Repeat the above steps by installing the spark tester on #4 and grounding #1. Do the same for #2 and #3 spark plug wires making sure the companion wire is grounded.

Does the spark tester spark on all cylinders?

--

Go to Step 7

Go to Step 11

7
  1. Turn OFF the ignition.
  2. Inspect for malfunctioning spark plugs. Refer to Spark Plug Inspection .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 8

8

Inspect for basic engine problems. Refer to Symptoms - Engine Mechanical in Engine Mechanical.

Did you find and correct any conditions?

--

Go to Step 25

Go to Diagnostic Aids

9
  1. Connect the harness connector to the CKP sensor.
  2. Disconnect the harness connector from the PCM.
  3. Measure the resistance between the CKP sensor circuits.

Is the resistance within the specified value?

500-900 ohms

Go to Step 24

Go to Step 10

10

Test the CKP signal circuit and the low CKP reference circuit for the following conditions:

    • An open
    • High resistance
    • Circuits shorted together

Did you find and correct the condition?

--

Go to Step 25

Go to Step 19

11
  1. Turn OFF the ignition.
  2. Remove the spark plug jumper wires.
  3. Remove the ignition control module from the ignition coil housing. Refer to Ignition Control Module Replacement .
  4. Confirm that the interconnect is connected to the ICM module.
  5. Turn ON the ignition, with the engine OFF.
  6. Measure the voltage between the primary ignition coil voltage circuit and the ICM interconnect and a good ground.

Does the voltage measure near the specified value?

Battery Voltage

Go to Step 12

Go to Step 13

12
  1. Remove the inner-connect from the ICM.
  2. Connect a J 43298 Ignition Module Tester in place of the ignition coils.
  3. Turn ON the ignition, with the engine OFF.
  4. Depress the test button while cranking the engine.
  5. Observe the tester.

Does the appropriate 1-4 and 2-3 LEDs flash ON and OFF as the engine is cranking?

--

Go to Step 22

Go to Step 15

13
  1. Turn OFF the ignition.
  2. Disconnect the ICM connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the ICM ignition 1 voltage circuit with the DMM.

Does the voltage measure near the specified value?

12 V

Go to Step 21

Go to Step 14

14

Test the ICM ignition 1 voltage circuit for the following:

    • An open
    • A short to ground

Did you find and correct the condition?

--

Go to Step 25

--

15
  1. Turn OFF the ignition.
  2. Disconnect the ICM connector.
  3. Connect a DMM from the affected IC timing control circuit to ground, set the DMM to AC voltage.
  4. Crank the engine.

Does the voltage measure within the specified range?

0.5-2 V

Go to Step 17

Go to Step  16

16

Test the affected IC timing control circuit for the following:

    • An open
    • A short to ground
    • A short to voltage
    • A short between the timing control circuits

Did you find and correct the condition?

--

Go to Step 25

Go to Step  23

17
  1. Turn OFF the ignition.
  2. With a test lamp connected to battery positive voltage, probe the ICM ground circuit.

Does the test lamp illuminate?

--

Go to Step 21

Go to Step 18

18

Test the ICM ground circuit for the following:

    • An open
    • A short to voltage

Did you find and correct the condition?

--

Go to Step 25

--

19

Inspect for poor connections at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 20

20
  1. Replace the CKP sensor. Refer to Crankshaft Position Sensor Replacement .
  2. Perform the CKP variation learn procedure. Refer to Crankshaft Position System Variation Learn .

Did you complete the replacement?

--

Go to Step 25

--

21

Replace the ICM. Refer to Ignition Control Module Replacement .

Did you complete the replacement?

--

Go to Step 25

--

22

Replace the ignition coil housing. Refer to Ignition Coil Housing Replacement .

Did you complete the replacement?

--

Go to Step 25

--

23

Inspect for poor connections at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 25

Go to Step 24

24

Replace the PCM. Refer to Powertrain Control Module Replacement .

Did you complete the replacement?

--

Go to Step 25

--

25

Attempt to start the engine.

Does the engine start and continue to run?

--

Go to Step 26

Go to Step 2

26
  1. Turn OFF the ignition for 30 seconds.
  2. Start the engine and operate the vehicle.
  3. Observe the MIL, vehicle performance, and driveability.

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

--

Go to Diagnostic Trouble Code (DTC) List

System OK