FL70 49 flash code question

[jcross]

Recently I disconnected my battery cables, pulled the speedometer out to look for something else and now my check engine light and engine heater light won't go out and the code it flashes is 49 which is "Inlet Air Heater Driver Fault" (open/closed circuit) or something like that.

I called CAT and he said it could be anything related to it (air heater) but that it was safe to drive.

Where is the air heater located?

When you turn the key you can hear it click like 6 times then I start it and it starts fine. But the heater and check engine lights stay on.

Suggestions?

 

[Deville]

I am pretty sure the inlet air heater is just a fancy name for Glow plug. They do wear out becoming less efficent over time. I've never replaced one, but I'm told they are easy to replace. They look like spark plugs I'm not sure how many are in the CAT 3126 if each cylnder head has it's own.

You may have knocked a wire off the instrument block when you were messing around back there. I was STUNED when I saw how much wiring was back there when i pulled my panel off. It's easy to knock somthing off & never find where it came from.

It may become difficult to start the motor is really cold weather. Outside of that you should be ok driving it.

The clicking noises you hear are various air vavles along the rail of the truck & air bags checking themselves.

 

[greg334]

It sounds like the heater relay may be going. They go bad because of the arcing within the relay - my heater (ISC not 3126) draws about 200 amps cold.

Chances are the relay is going, removing the cluster won't do much damage if any unless you decide to be a gorilla and yank on wires. The heater has zero wiring from the cluster to be harmed by it. The ECM controls the relay that controls the heater.

If it is an inlet heater, it is a BIG metal grid that is placed right in the path of the charge cooler outlet into the intake - on the intake. They don't go bad often, it has to be something dramatic to cause it to go bad.

Try changing the relay out, it is not hard to do and if you can take the cluster out, you can do the relay. As to the location and which one, talk to CAT or FL about that.

 

[jcross]

greg334....I put a multimeter on the air heater, relay and then on both and the meter read that they were working.

Also, when these two lights came on my power windows quit working. I called Freightliner and they told me they didn't have any idea which fuse went to them (power windows) as they were all different and its not shown in my owners manual. So I pulled all the fuses looking for something obvious and found nothing....but when I turned the key on the check engine light went out as did the air heater light and my windows went back to working. That lasted about 3 days.

Well, today the same thing the truck starts and runs good but those two lights are on and no power windows.

I'm still not sure what fuse goes to the power windows (or relay) this thing is getting frustrating.

 

[greg334]

You may have a ground problem.

 

[jcross]

You're right it may be a ground problem. I've already cleaned and tightened the one below the fuel filter on the outside of the drivers side frame rail, the one below the starter on the inside of the frame rail, cleaned the posts on the starter, clean the posts on the batteries, the one of the side of the engine above the ECM. I'll keep looking for more of them.

 

[Deville]

Since the prolbems started when u pulled the Battery connections Have u tried disconecting Waiting a few mins & reconnecting the Batteries again? Than I would look behind the instrument panel again & check all the wies coming off the Idiot lights & try to trace them. U may have pulled somthing off behind the panel when u streched the wires out.

What year is your truck? It could be an actual wire harness issue going to the ECM.

 

[jcross]

The truck is a 1998 with a remanufactured engine in it. I've left the battery cables disconnected overnight this past week.

It's electrical somewhere and giving me fits.

 

[Deville]

So all this happened AFTER u pulled the panel off to get behind the instrument panel? Why did u pull the panel off in the 1st place?