08' 550 Radiator Fan or Fan Relay malfunction
Thread Starter
Junior Member
Joined: Sep 2012
Posts: 59
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From: OHIO
2005 E55 AMG / 2008 GL550
08' 550 Radiator Fan or Fan Relay malfunction
Hey everyone,
Anybody ever have to replace the radiator fan relay or the fan itself? Just wondering if this is a common failing part. I will post up the CEL code tomorrow
Anybody ever have to replace the radiator fan relay or the fan itself? Just wondering if this is a common failing part. I will post up the CEL code tomorrow
Thread Starter
Junior Member
Joined: Sep 2012
Posts: 59
Likes: 0
From: OHIO
2005 E55 AMG / 2008 GL550
Ok, so here are the codes...
P0116
P0300
P0301
P0305
Please, somebody correct me if I'm wrong but the 0116 code is some (ECT) sensor Engine Coolant Temp? I'm assuming the rest of the 300 series codes are misfires because of the 0116 code???
I thought it is was the fan because I never heard it power on, but I guess this sensor has something to do with it coming on too?
P0116
P0300
P0301
P0305
Please, somebody correct me if I'm wrong but the 0116 code is some (ECT) sensor Engine Coolant Temp? I'm assuming the rest of the 300 series codes are misfires because of the 0116 code???
I thought it is was the fan because I never heard it power on, but I guess this sensor has something to do with it coming on too?
Last edited by Ike Luv; Nov 2, 2013 at 09:54 PM.
MBWorld Fanatic!
Joined: Dec 2004
Posts: 4,268
Likes: 253
That engine gets hot very quickly. Are you observing overheating coolant?
Let the truck idle for a bit after you drove it. The fan should cycle on and off as needed. Does it?
Misfires due to overheating suggest very high engine temps - do you observe such temps? See above... My guess is the misfires are not due to engine temps.
Let the truck idle for a bit after you drove it. The fan should cycle on and off as needed. Does it?
Misfires due to overheating suggest very high engine temps - do you observe such temps? See above... My guess is the misfires are not due to engine temps.
Thread Starter
Junior Member
Joined: Sep 2012
Posts: 59
Likes: 0
From: OHIO
2005 E55 AMG / 2008 GL550
That engine gets hot very quickly. Are you observing overheating coolant?
Let the truck idle for a bit after you drove it. The fan should cycle on and off as needed. Does it?
Misfires due to overheating suggest very high engine temps - do you observe such temps? See above... My guess is the misfires are not due to engine temps.
Let the truck idle for a bit after you drove it. The fan should cycle on and off as needed. Does it?
Misfires due to overheating suggest very high engine temps - do you observe such temps? See above... My guess is the misfires are not due to engine temps.
When I let it idle , the red meter pops back up like its going to overheat. The fan never cycles on.
It seems like it started to misfire when the coolant meter popped up. I physically felt the stutter of the motor after that.
Do you think this comes from the fan not cycling on?
MBWorld Fanatic!
Joined: Dec 2004
Posts: 4,268
Likes: 253
Fan circuitry needs to be tested via das and if malfunctioning the troubleshooting tree in das can be utilized to divide and conquer.
There could be some backyard mechanic tricks to troubleshoot this in other ways but I am not aware of them.
The only way a misfire will occur after overheating is if ignition coil(s) have been cooked and/ or plugs got glazed. Not sure this has happened though.
There could be some backyard mechanic tricks to troubleshoot this in other ways but I am not aware of them.
The only way a misfire will occur after overheating is if ignition coil(s) have been cooked and/ or plugs got glazed. Not sure this has happened though.
Thread Starter
Junior Member
Joined: Sep 2012
Posts: 59
Likes: 0
From: OHIO
2005 E55 AMG / 2008 GL550
Fan circuitry needs to be tested via das and if malfunctioning the troubleshooting tree in das can be utilized to divide and conquer.
There could be some backyard mechanic tricks to troubleshoot this in other ways but I am not aware of them.
The only way a misfire will occur after overheating is if ignition coil(s) have been cooked and/ or plugs got glazed. Not sure this has happened though.
There could be some backyard mechanic tricks to troubleshoot this in other ways but I am not aware of them.
The only way a misfire will occur after overheating is if ignition coil(s) have been cooked and/ or plugs got glazed. Not sure this has happened though.
So, I cleared the codes with a small ODB II scanner I have & the cleared the CEL. Its been 2 days since it has been out but I still don't hear the fan cycle on. My next step is to get the circuitry tested on that fan like you suggested, I'm also just gonna try to swap out that coolant sensor. You have any idea how big of a job that sensor is?
Joined: Jul 2021
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cls500
Cls 500 2006
Radiator fan won’t turn on so I got a new fan I changed the relay And fuse and coolant temp sensor still nothing so I check the fan power source and I get three green lights and one red fan is receiving constant power it has ground and also has power from the yellow wire I believe but the green wire stays at a constant green light on my probe I believe it turns to ground when fan is sent the signal to turn on so I believe it’s my ecm that’s not sending the signal … dont know what to do I’m kinda stuck as well
