Check Engine light?

[CrankyManBaby]

My 2010 ve calais has been giving me a Check Engine light warning. I took it straight to my mechanic and it showed a fault in the coolant level sensor. The level was fine? The mechanic cleared the fault and told me to see if the Check Engine light comes back. It did a week or so later, with the same result. He then changed the sensor and cleared the fault. The Check Engine light came back on a couple of week later. Mechanic had the same reading (coolant level sensor)? The mechanic then replaced the water cap with a new one cleared the fault and two weeks later the Check Engine light is on again??? I have yet to take it back to my mechanic as I have already spent $$$ to find it has not fixed the problem? Does anyone have any clues as to what step I take next? Thanks

 

[Capsule]

What’s the exact code? Could be a connector or harness issue affecting the ability for the ECU to fully access the sensor.

 

[CrankyManBaby]

Not sure of the code as the mechanic just told me it was the coolant level sensor. I am about to buy myself a

OBD-AUS Bluetooth Scan Tool – OBD2 Scan Tool​

to check it myself. It is due a service at the mo so I will book it in and let my usual mechanic deal with it this time and if it pops up again I will take it to Holden and let them use their scanner on it. I have only had the car a couple of months. Previously owned by a mechanic. He said he has done the following: Oil change every 7,500km. Timing chain Replaced about 25,000km ago with geniune holden parts. Had a major service at same time with new water pump, spark plugs and lots of other stuff.

 

[uglyoldfatbastard]

Have found with these cars that the sensors if not plugged and unplugged correctly seem to make the female side of the connector a bit loose. You can buy a terminal pin fit tension testing tool that helps make sure everything is making contact correctly. Seems a little weird but intermittent contact and vibration can give you heaps of engine codes and these tools help eliminate this. Ask your mechanic if he has a set or even if he has even heard of them

 

[CrankyManBaby]

Yeah I am finding that 'ALL SORTS' of things can set off the Engine Light; from low air in tires to fading batteries to a bug stuck on your wiper blade to dropping a french fry between your seats. I don't like the fact that you have to become your own mechanic to fix these probs. The one good thing about becoming that is that it saves you money from those who take the "steps of elimination" approach. Buy the time you have spent hundreds, if not thousands and find out all you had to do was inflate your tires to fix it just because they are too busy or proud to ask for help outside their own knowledge base.
I appreciate your suggestion and will ask if my mechanic if he has a terminal pin fit tension testing tool and I will also ask for a list of error codes from his diagnostic tool and update this feed as it comes to hand.

 

[CrankyManBaby]

OK I have used the diagnostic app and the error code is as follows...
P0128 (Coolant thermostat - coolant temperature below thermostat regulating temperature)
I have had the coolant sensor changed with a new one and this still comes up as the fault? Is the sensor different to the thermostat?

 

[Fu Manchu]

That doesn’t say the sensor is faulty. It says the sensor is reading data outside of what is ideal. That’s what fault codes are for. It’s doing its job. They don’t tell us what is broken. Unfortunately that is how most workshops treat them. They are the trained people. They should know that!

 

[Fu Manchu]

It could mean the thermostat is stuck open.

It’s on the back of the engine. Easiest access is with gearbox out. That is what is suggested by Holden. It’s how mine was done.

It can be done through the top but it’s like doing heart surgery blind folded and the job could easily need redoing. Getting all the clips for the wiper cowl are hard to find and the wiper cowl won’t fit the same. It all has to come off if going through the top.