DTC 46 - Mil (Service Engine Soon Light) Circuit Fault: Notes

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

The MIL (SERVICE ENGINE SOON) should always light when the ignition is on and the engine is not running for 2 seconds. The PCM controls the MIL and makes it light by providing a ground path. DTC 46 will set when no ignition voltage on the MIL (SERVICE ENGINE SOON light) control circuit when the PCM is requesting the MIL on. PCM will default to no MIL.

NOTE: Test numbers refer to numbers on diagnostic chart.

This step checks the PCM's ability to command the MIL.
This step determines if an open is present in the ignition feed circuit.