Electronic Ignition (EI) System Diagnosis. Pontiac Vibe

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2008 🢒 Vibe - FWD 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Electronic Ignition (EI) System Diagnosis

Diagnostic Instructions

•	Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

•	Review Strategy Based Diagnosis for an overview of the diagnostic approach.

•	Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Each engine cylinder has a dedicated ignition coil assembly. The ignition coil assembly contains the ignition module circuitry. The power distribution circuit supplies system voltage to each coil assembly when the ignition switch is in the ON or START positions. Each coil assembly regulates current flow through the primary coil windings, creating a magnetic field. The powertrain control module (PCM) signals each coil assembly to supply a spark in a cylinder through a trigger circuit. Each assembly does so by opening the primary circuit coil, inducing a high voltage in the secondary circuit coil. The high voltage in the secondary circuit grounds by arcing at the spark plug. This event creates a pulse on the fail safe circuit that the PCM recognizes as a confirmation of spark. The ignition coil consist of the following circuits:

•	The ignition 1 voltage circuit

•	The ignition trigger control circuit

•	The ignition fail-safe circuit

•	The ground circuit

Diagnostic Aids

Check for any of the following conditions:

•	Any circuit malfunction between the ignition coil assembly and the PCM should set a fail safe circuit DTC P0351, P0352, P0353, or P0354.

•

Check the crankshaft position (CKP) sensor engine reference signal with a scan tool. Observe the Engine Speed parameter while cranking the engine. The scan tool should indicate a steady 200-300 RPM while cranking. If erratic values, such as sudden spikes in the engine speed, are displayed, the engine reference signal is not stable enough for dependable ignition system operation.

•	An ignition system that tests OK after sitting may be susceptible to moisture. Spray water on the ignition system components and wiring in order to check for an intermittent failure.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

•	Powertrain Control Module Connector End Views

•	Engine Controls Connector End Views

Description and Operation

Electronic Ignition (EI) System Description

Electrical Information Reference

•	Circuit Testing

•	Connector Repairs

•	Testing for Intermittent Conditions and Poor Connections

•	Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 26792 Spark Tester

Circuit/System Testing

Important:

•	Do not perform this diagnostic procedure if you were not sent here from a misfire DTC or the Engine Cranks but Does Not Run diagnostic.

•	The following tests must be performed on each ignition coil.

Ignition OFF, remove the ignition coil assembly.
Verify the ignition coil spark plug boot and terminal do not have carbon tracking or corrosion.

⇒	If the condition exists, replace the ignition coil and spark plug.

Connect a J 26792 Spark Tester or an equivalent to the spark plug boot of the ignition coil assembly.
Connect the J 26792 to ground.
Connect the coil assembly electrical connector.
Crank the engine and observe the J 26792 . There should be a crisp blue spark.

⇒	If there is no spark, switch the coil with one that has good spark. Test again with the J 26792 for spark. If still no spark, replace the PCM.

If all tests are normal, replace the ignition coil.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Spark Plug Replacement

•	Ignition Coil Replacement

•	Control Module References for PCM replacement, setup, and programming