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.

If engine starts, code is intermittent.
This test checks for an IC signal from PCM to ignition coil driver.
Remaining tests check driver circuitry. Because coil driver gets its power from coil, check ignition coil feed circuit to ignition coil for opens.

Fig 1: Code 42 Schematic (Corvette) IC Circuit Grounded

Fig 2: Code 42 Diagnostic Flow Chart (Corvette) IC Circuit Grounded