Code 42, Ignition Control: Notes
WARNING: This page is about a different car, the 1995 Pontiac Trans Sport and 1995 Chevrolet Lumina APV. However, it is still accessible from the selected car via links, so may be relevant.
Code 42 indicates control module has seen an open or short to ground in Ignition Control (IC) or by-pass circuits.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- This test confirms Code 42 and determines if fault is a hard failure or intermittent condition.
- This tests for a normal IC ground path through ignition module. If circuit is shorted to ground, reading will be less than 500 ohms.
- As test light voltage touches by-pass circuit, module should switch. This causes ohmmeter to "over-range" with meter in 100-200 ohm range. A higher ohm range will indicate over 5000 ohms. This test assures module switched.
- If module did not switch, this step tests for a short in IC circuit, an open in by-pass circuit and a faulty ignition module connection or module.
- This step confirms Code 42 is a faulty control module and not an intermittent problem in IC and by-pass circuits.