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Post by andy33 on Nov 1, 2023 20:04:55 GMT
Hello Everyone,
I have the following problem :
Engine: CJSA kW ( hp) l
Mileage: 141041 km
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01 Engine
System description: 1.8l R4 TFSI
Software number: 8V0906264B
Software version: 0003
Hardware number: 06K907425A
Hardware version: H09
Faults:
P194B00 - Coolant pump locked
Intermittent
Priority - 2
Malfunction frequency counter - 3
Unlearning counter - 255
km-Mileage - 140535 km
Engine speed - 0.00 1/min
Normed load value - 0.0 %
Vehicle speed - 0 km/h
Coolant temperature - 90 °C
Intake air temperature - 27 °C
Ambient air pressure - 980 mbar
Voltage terminal 30 - 12.539 V
Dynamic environmental data - 209628110E0011EC0011DC000011ED6210A601E911EE2911DB05A9
The car has a new water pump as the old let go. The system is not blocked as it has been flushed multiple times and there is no bloackge in the system or heater matrix. Sometimes I get "hot" air and sometimes it just cold, the times where the "hot" air is more like warm air.
When the car turns off in auto shut off or after a long drive the temperature will increase in the temp gauge and in the live data of obd reaching +120C.
What can I do to fix the problem?
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Post by dv52 (Australia) on Nov 1, 2023 23:53:27 GMT
Hmm....... I'm fairly certain that a 1.8l R4 TFSI engine on MQB plaform cars (like this vehicle) is what VAG calls a CJSA engine.
If I'm correct, this engine actually has 2 x coolant pumps: the normal mechanical, belt-driven coolant pump and an electric pump - which is called the "Continued coolant circulation pump V51" in the wiring diagram. The electric pump is the noise that you can hear after the ignition is turned-off (it continues coolant flow until the engine temperature drops below a threshold setting)
I suspect that the P194B00 error is referring to V51 rather than the belt-driven pump. I assume it was the belt-driven pump that was replaced in your words "The car has a new water pump as the old let go")
So again if I'm correct, I suggest that you investigate the operation of V51 - it's a simple 3 x pin pump with a fused +12V supply pin, an earth pin and a control ON/OFF pin that's connected to the Engine module.
I suspect that the fuse is OK because it supplies battery rail volts to other stuff on the engine and your SCAN only has the ONE error. Nevertheless, check that 12V appears on pin#2 on the V51 connector without ignition-ON. Also check that the earth pin#1 is OK, that the general wiring-loom to the pump is sound and make sure that the connector is seated correctly.
After the engine has warmed-up and the ignition is turned-OFF - maybe place a large screwdriver on the pump housing with your ear on the handle - do you hear the pump spinning? If not - check that the control pin#3 on the V51 connector has volts!
Don
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Post by andy33 on Nov 2, 2023 22:47:45 GMT
Hi Don,
As far as I am aware the car with dual climate control have that fan integrated in the water pump, I can hear the pump going on when the car turns off. So I don't know how this is happening.
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Post by dv52 (Australia) on Nov 3, 2023 21:15:58 GMT
hmm........ OK. The fault is listed as "intermittent" - so I guess that it's not surprising that you can hear the pump working from time-to-time! I'm not sure how familiar you are with DC voltage motors (like those in the coolant pump) - but the electrical current in these motors increases as the load on the pump increases. I'm guessing that a fault like "pump locked" means that the monitoring circuit in the Engine module has detected that the electrical current that the pump is drawing is too high. Now, there could be a number of different reasons why the pump is drawing high amperes including a faulty motor winding, defective wiring, broken impeller etc. And again, the other complication in this case is the intermittent nature of the fault!! If this was my car - I would watch the Malfunction frequency counter in the freeze-frame data. This is a count of the number of times that the same error is re-registered by the Engine module in a subsequent ignition cycle. If this number starts to increase - maybe remove V51 and investigate it's operation?
Don
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Post by andy33 on Nov 22, 2023 20:23:42 GMT
Hi Don,
The issue seems to happen when the car turns off as previously mentioned. The temps will creep up but if I restart the car and then turn it off again it will cool down as if there wasn't any issues. So I am lost at this point, the only thing that stands out to me is the following:
Coolant temperature at radiator output, specified value -48.0 C.
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Post by dv52 (Australia) on Nov 24, 2023 20:51:53 GMT
Andy: I'm not sure about the coolant temperature reading -48.0 C. According to my information, the CJSA engine has 2 x temperature sensors - but if there are no reported errors relating to the sensors, I suggest (respectfully) that this is a "red-herring"! The locked pump error that is reported in your first post is consistent with your observation that "the issue happens when the car turns-off". As I said, this is the role of the electric pump V51.
And your other observation "if I restart the car and then turn it off again it will cool down as if there wasn't any issues" is also consistent with the fault classification that this is an intermittent problem. I'm also a tad puzzled by your assertion that "As far as I am aware the car with dual climate control have that fan integrated in the water pump". My information suggests that V51 is installed on ALL CJSA engines.
Do you have a copy of the repair manual for this engine? If so, look at section 2.6 - page 214. This shows the location of the electric coolant pump V51.
Don |
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