Hi,

I am a new 6.4 Diesel owner and new to the forum. My truck has 85k miles and has started displaying the Wrench light after starting up on cooler mornings ( 30 - 40 F). While the light is on, the idling increases to 1000 - 1200 rpms. Hitting the brakes lowers the idling.

The light disappears and does not return after I shut the truck off and cycle the the key. The truck runs and idles fine (~700 rpm) the remainder of the day after I cycle the key. I have only seen this issue a few times in the mornings; after the truck has set for several hours overnight.

Has anyone else experienced this issue or have any suggestions for troubleshooting it. Unfortunately, my scanner is not recognizing the code.

Also, I apologize if there is a thread already addressing this issue, but I have not been able to find it. If there is an existing thread that will guide me, please direct me to it. Thanks

 

If the wrench light came on there is a code waiting to be read, the high idle is normal, any time the truck runs when the water temp is under 165 degrees after something like 2 minutes it will gradually raise the idle until it get to 1100 RPM or so. Hitting the brake brings the idle down as so does running over 165 degrees water temperature.

 

You'll have to read the codes.....Does truck run rough when you first start it? Maybe one of your glow plugs has gone bad.

 

Thanks. The truck does run rougher than normal while the light is on. My scanner is about 8 years old and is not detecting a code with the wrench dash light. Can you recommend a scanner that I can purchase to read the wrench code. Or is most Autozone's scanners capable of reading the code?

 

Any auto parts store should be able to read your code. As for the high idle, that's a normal function on diesels.

 

Thanks everyone, I will head to the auto parts store. Are past codes retrievable when fault light is off or should I wait until it throws a fault light again?

 

Not exactly... Most generic scanners WILL NOT read many of the codes that set the wrench. One example is the tft sensor, ask me how I know... Even my cts wouldn't read the code. Hell... SnapOn scanners wouldn't read it, I needed to hook her up to an ids.

So, you need to get it into a shop and have the codes read. Even if the auto parts store scanner will read it, many times you will still have hidden codes.

Beyond that, the high idle actually depends on a variety of things. Yes, below 165* on a cold day it will high idle. But it is actually the air intake temp sensor that determines how high the idle is jumped and at what temp (well the pcm determines it based off of the sensor). Many tuners will modify this as well.

 

Ok, the dealership indicated the wrench light was a floor pedal sensor. They believe the my weathertech floor mats may be interfering and creating the light and recommended thinner floor mats. I will test their theory.

More importantly, I need to find a scanner that will read the fault codes on this truck.

 

They aren't cheap... You can get an Edge CTS but you still won't be able to read hidden codes.

Even high end snap-on scanners won't read them all, the only way to know you are seeing all of the dts is with an IDS... And trust me, its not worth the money you would spend on that.