High idle

[dimples0925]

My '97 with a 3.1 blew the PCM/Battery fuse, car was stuck on high idle after changing the fuse. When put on a computer, the TPS, MAP sensor, and mass air flow sensor codes came up. Changed all of these and find no vacuum leaks, still have high idle. Any ideas????

[GTP Dad]

What caused the fuse to blow? You may have a bad ecm due to an voltage spike that got past the fuse before it blew. Check Parts America (Advance Autoparts) for a reman unit or pick up one at a local wrecking yard. A whole lot cheaper than a new one. First, try disconnecting the battery and see if the ECM returns to default. If not a new one may be your only choice.

Your problem is similar to another thread but it is different since you had the fuse blow before the problem occurred.

Welcome to AF!!

[dimples0925]

Originally Posted by GTP Dad

What caused the fuse to blow? You may have a bad ecm due to an voltage spike that got past the fuse before it blew. Check Parts America (Advance Autoparts) for a reman unit or pick up one at a local wrecking yard. A whole lot cheaper than a new one. First, try disconnecting the battery and see if the ECM returns to default. If not a new one may be your only choice.

Your problem is similar to another thread but it is different since you had the fuse blow before the problem occurred.

Welcome to AF!!

Sorry, had the fuse wrong, it is the PCM/Battery fuse that blew and once changed caused a high idle.

[ajtkimmel]

That is the fuse you originally stated was blown. The ECM that "GTP DAD" mentioned, is the PCM, or your cars computer. Different names for the same part. Check local aftermarkets for one. They usually come with a 90 day warranty or so.

[corning_d3]

Before you spend the money on a PCM, make sure the idle control motor is working properly. After looking around a bit, I noticed the TPS, MAP and MAF sensors use the same 5 volt reference signal from the computer. I'd get a decent wiring diagram for the car and probe the 5V Ref. wire on all three sensors with a DVOM. If the voltage is even slightly above or below(5 or 10% threshold) 5 volts, there's probably a problem with the voltage regulator inside the PCM, which requires a PCM change. If you have to have another PCM, make sure it's the same make, model, engine and transmission combination as your vehicle. You'd have a 3100 engine and a 4T60E transmission..