jt-hifi

Hi Folks,

My 2010 S550 4Matic's yellow coolant temperature light comes on around 85 degree. The suction fan does not consistently want to turn on at this temperature. But, if it does, it is operating at high speed.

Star diagnostics threw the following fault codes:
0694: M4/7 (Engine and AC electric suction fan with integrated control) : Output stage
2366: Component M4/7 (Engine and AC electric suction fan with integrated control) has a malfunction.
2358: The control line to component M4/7 (Engine and AC electric suction fan with integrated control) has Short circuit to ground.

I stumbled into Star fan actuation, coolant temp sensor and three-disk thermostat tests and all three tests were able to move the fan. I don't know what to look for in the reading. I checked the W2 ground, no corrosion and connection is tight. I unplugged the connection to the fan and plugged it back in.

How can I tell if it is indeed the M4/7 suction fan that's faulty? Is there anything I can do with Star to test and isolate the problem is not the coolant temperature sensor or the three-disk thermostat valve?

Appreciate your help

John

konigstiger

Coolant sensor provides input to ECM that in turn communicates with fan. Erase all fault codes stored/current, run quick test - should identify malfunction. Check connections @ engine control unit viewed here: https://www.pacificmotors.com/auto-p...des-s550-w221/

jt-hifi

I erased the fault codes and replaced with a new coolant temperature sensor. The Coolant Temperature Warning light still comes on with the same exact errors:
0694: M4/7 (Engine and AC electric suction fan with integrated control) : Output stage
2366: Component M4/7 (Engine and AC electric suction fan with integrated control) has a malfunction.
2358: The control line to component M4/7 (Engine and AC electric suction fan with integrated control) has Short circuit to ground.

When the warning light comes on around 230F, the sensor signal voltage is 0.4V. Which I believe is the correct voltage value. I ordered another sensor just to rule out it is the problem.

I used the actuator to turn on the fan most of the time it would turn but ended in communication error 8.600.0. But, sometimes the fan would not turn on at all. Could it be the cooling fan that's faulty?

Thanks,

EasyPhil

If the fan is running full blast, the controller on the fan is toast. This is easy to test if you have another fan motor and controller. I had this problem with my W220 and an aftermarket unit, plugged in the original and it worked correctly, plugged in the the aftermarket unit and "Jet Engine Time". You may be able to find a used motor/controller and swap with the one you have.

jt-hifi

EasyPhil: The fan doesn't stay full blast all the time, the fan speed decreases proportionally as the temperature drops. But, the problem is the fan doesn't want to turn on automatically when temp goes above 80 or 90C. I ordered another aftermarket OEM coolant temp sensor and a fan (TOM AUTO PARTS brand) 2 days ago from eBay. I hope the aftermarket fan isn't giving me the "Jet Engine" problem that you have and can help me fix the problem.

What do folks think about aftermarket cooling fan in general? Do I need to initialize the new fan with STAR Diagnostics and set the fan speed?

JT

EasyPhil

If the speed of the fan decreases that means there's nothing wrong with it. The aftermarket fan I had got damaged because a hose broke due to age and coolant messed up the electronics in the controller. My fan was on high the moment you started the car.

dlafever

This seems to be pretty specific, have you been able to have a look at the harness and connectors? Might find some gunk/goo or a corroded connection or wire break somewhere along the path.

jt-hifi

I checked the harness and connectors, they seem fine. I disconnected the fan and measured the voltage of the connector, around 12V when engine is off and around 13V or 14V when on. The smaller prong measures around 3V. It suggests to me the wires are probably okay.

jt-hifi

Am I supposed to see different voltage readings on the connector to the suction fan when the Coolant Temperature warning comes on?

2 different voltage value per pin was measured when engine was off and on
Pin 1 (Brown): 0.06 Ohm, 0V
Pin 2 (Red): 12V, 14V
Pin 3 (Red-Green): 0V, 14V
Pin 4 (Red-Black): 0V, 3.18V

The voltages changed ever so slightly when the yellow coolant temp light came on. Does that mean that either the Coolant Temp Sensor or the ECU is not telling the Fan to turn on?
Pin 1 being 0.06 Ohm close to zero suggests that I probably don't have a ground fault?

jt-hifi

I replaced the cooling suction fan this afternoon and the problem went away. Yippee!

The problem wasn't coolant temp sensor, it's the fan controller which refused to turn the fan on when high engine temperature called for it.

Thanks for everybody's help!

verlin samonte

this looks similar to my problem, different benz model though. just a clarifcation, on your defective suction you can actuate the fan using star, right? but upon replacing the fan, no more error?