Car won't crank radiator fan runs high speed
06-07-2020, 04:48 AM
#1
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Car won't crank radiator fan runs high speed
Was driving the car in the morning for about 5 mins when I lost power. Looked at the instrument cluster to see
1. Coolant temperature too high warning message with temperature light in red colour
2. No visible bars in the temp gauge cluster
Stopped the car switched off and switched on and car didn't crank
3. Radiator fan started running at full speed until I switched off the key
checked random fuses, wiggled them and wiggled the relays of the front SAM. No difference. Tried to scan the car using a basic bluetooth adaptor which I usually use to read fault codes. It didn't get connected (fried SAM or ECU?). Call me it's a placebo effect but I smelled something funny under drivers floor but didn't inspect anything.
Car is now at workshop waiting for diagnosis. Any suggestions for me to advise the guys to look into rather than replace SAM or ECU
1. Coolant temperature too high warning message with temperature light in red colour
2. No visible bars in the temp gauge cluster
Stopped the car switched off and switched on and car didn't crank
3. Radiator fan started running at full speed until I switched off the key
checked random fuses, wiggled them and wiggled the relays of the front SAM. No difference. Tried to scan the car using a basic bluetooth adaptor which I usually use to read fault codes. It didn't get connected (fried SAM or ECU?). Call me it's a placebo effect but I smelled something funny under drivers floor but didn't inspect anything.
Car is now at workshop waiting for diagnosis. Any suggestions for me to advise the guys to look into rather than replace SAM or ECU
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Krisuu (07-26-2022)
07-26-2022, 02:47 PM
#7
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MY'14 W212 M276 3.5NA @55kMi
ECU madness
No crank + full speed fan... that's pretty extreme 😳
1- check the data value for your COOLANT TEMP!
2- then physically inspect the sensor connector pins
3- then look over data again for any change
With engine cold you expect near ambient temp +/- 15%
1- check the data value for your COOLANT TEMP!
2- then physically inspect the sensor connector pins
3- then look over data again for any change
With engine cold you expect near ambient temp +/- 15%
Last edited by CaliBenzDriver; 07-26-2022 at 02:53 PM.
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07-28-2022, 10:51 AM
#8
Temperature was fine when I read it with computer. Sensor pins looks also good.
ECU have been tested and there was no problem. Also starter seems to be fine because i can get it crank with jumping starter relay.
07-28-2022, 12:31 PM
#9
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MY'14 W212 M276 3.5NA @55kMi
checking ECU supply....
CoolantTemp is OkECU reported Okstarter tested Ok> NO Start + Fan full speed: ECU not running...
> Next:
- Read OP about "driver side carpet...."
- Inspect both side front carpets for water/moisture
- Disconnect battery
- Clean the GND posts under said carpet.
- check ECU connector for Oil
- check front fuses
- Reboot computer by reconnecting battery
- Scan OBD port all modules
- read ECU live data
- report line item findings.
08-03-2022, 05:01 AM
#10
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