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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Vivant 🢒 Engine 🢒 Engine Controls - 2.0L (L34 GMDAT) 🢒 Electronic Ignition (EI) System Diagnosis

Electronic Ignition (EI) System Diagnosis European Emissions

Circuit Description

The electronic ignition (EI) system uses a waste spark method of spark distribution. In this type of EI system, the crankshaft position (CKP) sensor is mounted to the oil pump near a slotted wheel that is a part of the crankshaft pulley. The CKP sensor sends reference pulses to the engine control module (ECM). The ECM then triggers the EI system ignition coil. Once the ECM triggers the EI system ignition coil, both of the connected spark plugs fire at the same time. One cylinder is on its compression stroke at the same time that the other is on the exhaust stroke, resulting in lower energy needed to fire the spark plug in the cylinder on its exhaust stroke.

This leaves the remainder of the high voltage to be used to fire the spark plug in the cylinder on its compression stroke. Since the CKP sensor is in a fixed position, timing adjustments are not possible or needed.

Step

Action

Values

Yes

No

Caution: When working on the engine ignition system, use only electrically insulated pliers when handling ignition wires with the engine running. The ignition system produces high voltage while the engine is running and could cause serious personal injury if not handled properly.

1
  1. Remove the spark plugs.
  2. Inspect for wet spark plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits.
  3. Replace the spark plugs as needed.

Is the repair complete?

--

System OK

Go to Step 2

2

Test for the presence of spark from all of the ignition wires while cranking the engine.

Is spark present from all of the ignition wires?

--

System OK

Go to Step 3

3
  1. Measure the resistance of the ignition wires.
  2. Replace any ignition wires with a resistance above the value specified.
  3. Test for the presence of spark from all of the ignition wires.

Is spark present from all of the ignition wires?

30,000 ohms

System OK

Go to Step 4

4

Is spark present from at least 1 of the ignition wires, but not all of the ignition wires?

--

Go to Step 5

Go to Step 12

5
  1. Turn OFF the ignition.
  2. Disconnect the electronic ignition (EI) system ignition coil connector.
  3. While cranking the engine, measure the voltage at the EI system ignition coil connector terminal 1.

Does the voltage fluctuate within the specified range?

0.2-2 V

Go to Step 8

Go to Step 6

6

Inspect for an open in the wire from the EI system ignition coil connector terminal 1 to the engine control module (ECM) connector terminal M33/M1.

Is the condition found?

--

Go to Step 7

Go to Step 11

7
  1. Repair the wiring as needed.
  2. Connect the EI system ignition coil connector.
  3. Test for the presence of spark from all of the ignition wires.

Is spark present from all of the ignition wires?

--

System OK

--

8

While cranking the engine, measure the voltage at the EI system ignition coil connector terminal 2.

Does the voltage fluctuate within the specified range?

0.2-2 V

Go to Step 10

Go to Step 9

9

Inspect for an open in the wire from the EI system ignition coil connector terminal 2 to the ECM connector terminal M51/M35.

Is the condition found?

--

Go to Step 7

Go to Step 11

10
  1. Replace the EI system ignition coil. Refer to Ignition Coil Replacement .
  2. Connect the EI system ignition coil connector.
  3. Test for the presence of spark from all of the ignition wires.

Is spark present from all of the ignition wires?

--

System OK

--

11
  1. Replace the ECM. Refer to Engine Control Module Replacement .
  2. Connect the EI system ignition coil connector.
  3. Test for the presence of spark from all of the ignition wires.

Is spark present from all of the ignition wires?

--

System OK

--

12
  1. Turn OFF the ignition.
  2. Disconnect the crankshaft position (CKP) sensor connector.
  3. Measure the resistance between the CKP sensor terminals 1 and 2.
  4. Measure the resistance between the following terminals:
    5. • Terminals 1 and 3 of the CKP sensor
    • Terminals 2 and 3 of the CKP sensor

Is the resistance within the specified range?

400-600 ohms

Go to Step 14

Go to Step 13

13

Replace the CKP sensor.

Is the repair complete?

--

System OK

--

14
  1. Turn ON the ignition.
  2. Measure the voltage between the CKP sensor connector terminals 1 and 3.

Is the voltage within the specified range?

0.95-1.10 V

Go to Step 20

Go to Step 15

15

Measure the voltage between the CKP sensor connector terminal 1 and ground.

Is the voltage within the specified range?

0.95-1.10 V

Go to Step 18

Go to Step 16

16

Inspect the wire between the CKP sensor connector terminal 1 and the ECM connector terminal M21 for an open or short.

Is the condition found?

--

Go to Step 17

Go to Step 10

17

Repair the wire between the CKP sensor connector terminal 1 and the ECM connector terminal M21.

Is the repair complete?

--

System OK

--

18

Inspect the wire between the CKP sensor connector terminal 3 and ground for an open or short.

Is the condition found?

--

Go to Step 19

Go to Step 11

19

Repair the wire between the CKP sensor connector terminal 3 and ground.

Is the repair complete?

--

System OK

--

20
  1. Turn ON the ignition.
  2. Measure the voltage between the CKP sensor connector terminals 2 and 3.

Is the voltage within the specified range?

0.95-1.10 V

Go to Step 24

Go to Step 21

21

Measure the voltage between the CKP sensor connector terminal 2 and ground.

Is the voltage within the specified range?

0.95-1.10 V

Go to Step 18

Go to Step 22

22

Inspect the wire between the CKP sensor connector terminal 2 and the ECM connector terminal M5 for an open or short.

Is the condition found?

--

Go to Step 23

Go to Step 11

23

Repair the wire between the CKP sensor connector terminal 2 and the ECM connector terminal M5.

Is the repair complete?

--

System OK

--

24
  1. Turn OFF the ignition.
  2. Connect a test light between the EI system ignition coil connector terminal 2 and ground.
  3. Turn ON the ignition.

Is the test light ON?

--

Go to Step 27

Go to Step 25

25

Inspect for an open in the wiring between the EI system ignition coil connector, terminal 2, and the main relay connector terminal 30.

Is the condition found?

--

Go to Step 26

Go to Main Relay Circuit Diagnosis

26

Repair the open in the wiring between the EI system ignition coil connector terminal 2 and the main relay connector terminal 30.

Is the repair complete?

--

System OK

--

27

Inspect for damage in the terminal of the EI system ignition coil connector and repair as needed.

Is the repair complete?

--

System OK

--