Chipp

The check engine light on my car is still turned on even after replacement of the coolant bypass valve and switch, as per the codes. Does anyone have a clue what else needs fixing?

Thanks in advance for your advice

CODES:

1) P2681 - Engine Coolant Bypass Valve Control Circuit/open
2) P0116 - Engine Coolant Temperature Sensor 1 Circuit Range/Performance
3) P2181 - Cooling System Performance

jagtoes

So do we assume you erased the codes in the OBDII port. If so did they just come back.

Chipp

Exactly right. The codes were erased twice and came back

Do you think the other 2 temperature sensors/switch require replacing?

Or possibly the Passenger (backseat) air-con coolant bypass valve needs replacing?

jagtoes

Usually code "stack" meaning that the 1st code is the problem and it triggers the follow on codes. What was your 1st code and did you check that component for it's electrical value prior to replacing it.

Chipp

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First code is P2681 coolant bypass valve that was replaced by a mechanic, I assume they followed the protocol and tested the electrical value of the parts before installing it.

That being said, only 1 of the 3 switches was replaced

Chipp

This is the first code:
1) P2681 - Engine Coolant Bypass Valve Control Circuit/open

I'm assuming the mechanic followed standard protocol and tested the electrical value before putting in the new part.

Only 1 of 3 switches was replace though, do you think the other 2 switches may be faulty?

jagtoes

I would not ASSUME anything. Now days I find that "mechanics" just replace parts instead of diagnosing the problem. Someone should be able to check the circuit with a meter to verify if the other switches are working correctly. By the way did you ask him for the bad parts.

Chipp

Thanks, I can ask the mechanic to do a check of the circuit for all switches

I did get the original bypass valve back, the entire part is sealed so unsure if the original part is actually faulty

chuckwp

Sometimes it is easier to go with a educated guess and replace a suspect part if it is not too costly. Example is replacing a $75 part is way lest expensive than spending 4 hours trying to prove it is bad. This does not always work but, in the cases of know problems it often does. The increasing over complexity and over engineering of cars today makes it increasingly difficult to properly diagnose electronic related problems. I, being an older tech. did not start working on cars because I like geeky high tech computer stuff. That is fine as there is a whole new generation to deal with that and that like it! The other problem is that the majority of people that buy these cars think they are good because they are so expensive. Those people scream the loudest when you tell them it took 6 hours of labor time and a $1500 part to repair their vehicle.

jegoalv2090

I have the same error code on my Audi A4 1.8 2013, could anyone tell me where i can find the coolant bypass valve, please.