QuestionA 2000 Tiburon code P1586 I have been to HMA and it said it could be a pin to the ECM or a inhibitor switch. What is the inhibitor switch?
AnswerI'm glad you've asked this question, because it's enabled me to research and learn some things I wasn't previously aware of.
Near as I can figure, P1586 indicates a problem with the engine control module (ECM) receiving the proper signal from the inhibitor switch (also called a range switch). I use the "near as I can figure" language since I cannot find anywhere that actually specifies a concrete meaning for this code.
The inhibitor switch is the switch that attaches to an automatic transmission underneath the shift lever on the transmission. It sends signals to the ECM and TCM regarding the shift lever position, and allows the starter motor to be engergized when the shifter is in neutral or park.
Presuming you've also checked the TCM for diagnostic trouble codes (DTCs) and none were present, it's unlikely the inhibitor switch is your issue. Both the TCM and ECM depend on signals from the inhibitor switch, and the signals are much more critical for the TCM.
I was able to locate a technical service bulletin (03-40-001), which describes a corrosion problem with the transmission diode with 2000 to 2002 Accents. Although you don't have the same model and the likelihood of corrosion isn't as likely, it's quite possible you have some sort of problem with this diode.
Unfortunately, the service manual and schematic don't specify the exact location of this diode. The best I can offer is that it's in the main dash harness between connector EM02 and MC02, meaning it's probably somewhere in the vicinity of the block of large electrical connectors behind the left side of the dash taped into the harness.
I encourage you to look at the transmission schematic for your car at www.hmaservice.com and look at the in-line connector diagrams for EM02 and MC02 so you have a better understanding of the location I'm talking about.
