Test Description

WARNING: This page is about a different car, the 1995 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Test numbers refer to numbers on diagnostic chart.

Determines if code is intermittent.
This step determines if IC signal from PCM is available at ignition coil driver. IC circuit voltage should be between about .5 volt and 4.5 volts.
Remaining steps ensure coil driver circuitry is okay. If all wiring and connections are okay, check ignition coil and ignition coil voltage supply.

Fig 1: Code 41 Schematic (Corvette) Opti-Spark Ignition System Open Or Shorted EST Circuit

Fig 2: Code 41 Diagnostic Flow Chart (Corvette) Opti-Spark Ignition System Open Or Shorted EST Circuit