Originally Posted by als99r/t
...try flushing the engine and radiator out on it ... id also flush the heater core out real good on it...
Thank you for the response I appreciate it.
I have seen this response in other forums on the web, all with the same result...not effective. That makes sense to me since this error code is an open circuit code and not a fluid level or clarity indication, unless I'm missing something such as a sensor in the low speed fan circuit that would be effected by the fluid clarity. Is there one? I have not heard of anything along those lines except possibly the temperature sensing gage and that would not provide an open circuit indication because of the fluid needing flushed. It might provide an open circuit indication if it were malfunctioning (assuming it is even in the low speed fan circuit), but that would be indicated by the lack of the temperature gage on the dash to track engine temperature. Since I have validated that the temperature gage is indeed tracking the engine temp properly we can therefore assume that the temp sensor is working properly.
... try another low speed fan relay,its possible you got a bad one from the parts store ... part of the relay can be good and the other part bad,so yes in answer to your question it could still be a bad relay on it...
To preclude that possibility I set up a functional test bench and performed a complete functional test of the relay on the test bench. All aspects of the relay are functioning properly.
This brings us back to the original questions:
What exactly constitutes the “low speed fan circuit” that is being monitored by the computer for this error code?
What other possibilities are there in this circuit that could cause this error code and how do I test them?