GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2004 🢒 Epica 🢒 Engine 🢒 Engine Controls - 2.0L (L34 GMDAT) 🢒 DTC 063

Circuit Description

The electronic ignition (EI) system ignition coil is supplied with battery voltage when the ignition is ON. The electronic control module (ECM) triggers the circuit for the EI system ignition coil. Voltage is then induced in the secondary portion of the EI system ignition coil. Control of the EI system ignition coil is monitored separately for the 2 electronic spark timing lines.

Conditions for Setting the DTC
    • No voltage is supplied by the ECM through the electronic spark timing B line while reference pulses are received by the ECM from the crankshaft position sensor.
    • This error occurs over 6 times.

Diagnostic Aids
    • Inspect the ECM harness connectors for backed-out terminals, improperly formed or damaged terminals, a poor terminal-to-wire connection, and a damaged wiring harness.
    • If connections and the harness are OK, connect a digital voltmeter or an oscilloscope between the affected terminal and ground while moving the related connectors and the wiring harness. If the fault is induced, the voltage reading or the scope pattern will change.

Step

Action

Values

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - Engine Controls

2
  1. Disconnect the EI system ignition coil connector.
  2. Inspect the electronic ignition (EI) system ignition coil connector terminals to ensure that the terminals are correctly installed and none of them are touching.

Is the problem found?

--

Go to Step 9

Go to Step 3

3
  1. Connect a voltmeter between terminal A and terminal C of the EI system ignition coil.
  2. Crank the engine.

Does the voltage fluctuate within the value specified?

0.2-2 V

Go to Step 4

Go to Step 10

4
  1. Turn the ignition to LOCK.
  2. Disconnect the engine control module (ECM) white connector.
  3. Inspect for any damaged pins or terminals at or near the ECM connector terminal D14.

Is the problem found?

--

Go to Step 9

Go to Step 5

5

Inspect for an open or short to ground between the EI system ignition coil connector terminal A and the ECM connector terminal D14.

Is the problem found?

--

Go to Step 7

Go to Step 6

6

Inspect for an open or short to ground between the EI system ignition coil connector terminal A and the ECM connector terminal D14 while moving the connectors and the wiring harness of the ignition circuit.

Is the problem found?

--

Go to Step 7

Go to Step 8

7
  1. Repair the open or short to ground between the EI system ignition coil connector terminal A and the ECM connector terminal D14.
  2. Clear any DTCs from the ECM.
  3. Perform the Diagnostic System Check.

Is the repair complete?

--

System OK

--

8

Inspect the wires and wiring harnesses of the ignition circuit for any damage that could cause an intermittent open or short to ground.

Is the problem found?

--

Go to Step 9

Go to Step 11

9
  1. Repair any wire or connector terminal as needed.
  2. Clear any DTCs from the ECM.
  3. Perform the Diagnostic System Check.

Is the repair complete?

--

System OK

--

10
  1. Turn the ignition to LOCK.
  2. Replace the EI system ignition coil assembly. Refer to Ignition Coil Replacement .
  3. Clear any DTCs from the ECM.
  4. Perform the Diagnostic System Check.

Is the repair complete?

--

System OK

--

11
  1. Replace the ECM. Refer to Engine Control Module Replacement .
  2. Perform the Diagnostic System Check.

Is the repair complete?

--

System OK

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