Cooling fans run continuously on high
Thread Starter
Member
Joined: Nov 2017
Posts: 75
Likes: 30
ML63 W166
Cooling fans run continuously on high
Assistance and advice Please ML63 (2014 W166)
Car was running fine then fueled up and then when i started up the cooling fan came on full blast after a few seconds. (ambient 19 Celsius /66 Fahrenheit )
air conditioner is OFF (although the fresh air vent blower was on)
I noted the Green start / stop light was no longer lit on my dash. (no ECU light or any other unusual light lit up)
I noticed the temperature gauge was down low/cold and after 5 minutes of driving the temperature was back to normal but the fans are still on full blast.
I stopped for 15 minutes then started up and again temp was low/cold but built up quick after 5 minutes of driving, fan still on full blast.
car seams to be running fine, and maybe the transmission is hanging onto gears a little longer than normal (maybe)
have read a few posts and appears maybe temperature sensor on the motor or the A/C pressure sensor may be faulty.
when i get home today ill Put the OB11 analyser on it to see if I have recorded any faults.
anyone's opinion/ experience is welcome
Car was running fine then fueled up and then when i started up the cooling fan came on full blast after a few seconds. (ambient 19 Celsius /66 Fahrenheit )
air conditioner is OFF (although the fresh air vent blower was on)
I noted the Green start / stop light was no longer lit on my dash. (no ECU light or any other unusual light lit up)
I noticed the temperature gauge was down low/cold and after 5 minutes of driving the temperature was back to normal but the fans are still on full blast.
I stopped for 15 minutes then started up and again temp was low/cold but built up quick after 5 minutes of driving, fan still on full blast.
car seams to be running fine, and maybe the transmission is hanging onto gears a little longer than normal (maybe)
have read a few posts and appears maybe temperature sensor on the motor or the A/C pressure sensor may be faulty.
when i get home today ill Put the OB11 analyser on it to see if I have recorded any faults.
anyone's opinion/ experience is welcome
Thread Starter
Member
Joined: Nov 2017
Posts: 75
Likes: 30
ML63 W166
fitted the iSoft MB OB2 analyser result is P050C64
"the coolant temperature of the combustion engine is implausible during a cold start. there is an implausible signal "
Control Unit MED177_M157-CAN
MB number 2789011300
P050C Cold Start Engine Coolant Temperature Performance (obd-codes.com)
a little research suggest the coolant sensor may be at fault.
Anyone with any wisdom they can share?
"the coolant temperature of the combustion engine is implausible during a cold start. there is an implausible signal "
Control Unit MED177_M157-CAN
MB number 2789011300
P050C Cold Start Engine Coolant Temperature Performance (obd-codes.com)
a little research suggest the coolant sensor may be at fault.
Anyone with any wisdom they can share?
Thread Starter
Member
Joined: Nov 2017
Posts: 75
Likes: 30
ML63 W166
SOLUTION PENDING. for those interested or who may come up with the same problem.
I was all prepared to replace the coolant temperature sensor and when i went to put the car up on the ramps to start work HEY PRESTO problem was gone.
WHAT DID I DO?? removed the left air filter to do some investigation as to the location of the coolant temperature sensor (located below the left hand head)
ALSO pushed the connector to the fan which was in place (but the moving of the connector I believe was the solution) this indicates potentially a poor connection at the plug and probably result in a reoccurrence of the problem.
SO if this problem occures again , hopefully i know where to look, I put the OB11 analyser on to check codes and noted the fault codes had cleared.
I was all prepared to replace the coolant temperature sensor and when i went to put the car up on the ramps to start work HEY PRESTO problem was gone.
WHAT DID I DO?? removed the left air filter to do some investigation as to the location of the coolant temperature sensor (located below the left hand head)
ALSO pushed the connector to the fan which was in place (but the moving of the connector I believe was the solution) this indicates potentially a poor connection at the plug and probably result in a reoccurrence of the problem.
SO if this problem occures again , hopefully i know where to look, I put the OB11 analyser on to check codes and noted the fault codes had cleared.
Newbie
Joined: Nov 2025
Posts: 6
Likes: 3
2009 ML63
Your thread saved me hours!
I changed all the injectors on my ML63 last night, everything was fine except the radiator fan going full speed afterwards.
Saw your post today. Reseated the MAF plugs and some vacuum hoses.... problem solved!!!
I was about to pull out the xentry laptop and probably throw some sensors at it. Thank you!
I changed all the injectors on my ML63 last night, everything was fine except the radiator fan going full speed afterwards.
Saw your post today. Reseated the MAF plugs and some vacuum hoses.... problem solved!!!
I was about to pull out the xentry laptop and probably throw some sensors at it. Thank you!
Thread Starter
Member
Joined: Nov 2017
Posts: 75
Likes: 30
ML63 W166
Your thread saved me hours!
I changed all the injectors on my ML63 last night, everything was fine except the radiator fan going full speed afterwards.
Saw your post today. Reseated the MAF plugs and some vacuum hoses.... problem solved!!!
I was about to pull out the xentry laptop and probably throw some sensors at it. Thank you!
I changed all the injectors on my ML63 last night, everything was fine except the radiator fan going full speed afterwards.
Saw your post today. Reseated the MAF plugs and some vacuum hoses.... problem solved!!!
I was about to pull out the xentry laptop and probably throw some sensors at it. Thank you!
