1997 Jeep Wrangler (TJ) Trouble Codes

Ah, yes! The infamous 1997 TJ Check Engine Light; official designation, the Malfunction Indicator Lamp (MIL). If you have a 1997 TJ, then you have most likely had this stupid light gee on one time or another. What does it mean? What do you do when it gees on? And, most importantly, how do you turn the blasted thing OFF ?!?!?Keep in mind, this guide only applies to the 1997 Wrangler. It DOES NOT apply to 1996 or 1998 thru 2006 TJ, nor 2007 thru current JK and JKL models.The Powertrain Control Module (PCM) (a.k.a., the geputer or "black box") pictured below, is mounted to the firewall, under the hood, just above the battery. Its job is to monitor numerous different circuits in the fuel injection, ignition, emission, and engine systems. If the PCM senses a problem with a monitored circuit often enough to indicate an actual problem, it stores a Diagnostic Trouble Code (DTC) (a.k.a., an Error Code), in the PCM's memory. Diagnostic trouble codes that affect vehicle emissions will cause the Malfunction Indicator Lamp (MIL) (a.k.a., the Check Engine Light) to illuminate continuously while the engine is running. If the problem is repaired or ceases to exist, the PCM cancels the code after 40 warm-up cycles and the Malfunction Indicator (check engine) Lamp will go out.Note: Diagnostic Trouble Codes are the results of a system or circuit failure, but do not directly identify the failed geponent or geponents.