Pontiac Problems? Ask a Mechanic for Answers ASAP
Hi . Thank you for asking your question on JustAnswer.whats your questionThank you again for trusting us with your problem. John aka eauto
i have no diagrams today i will open this up for another expert
Have you replaced the ect yet?
What color is the coolant in the radiator?
First off the car should have an orange coolant in it called dex cool. Green antifreeze is to acidic for the aluminum in this engine, as well as the plastic. If you can unplug the ect and the fans will come on, then the ect has to be bad. The ecm is seeing that when it is unplugged, there is a problem and it is turn ng the fans on, so we know the rest of the system is still good. The ect does not run the temp gauge. The ect only tells the ecm what the temp of the engine is. The coolant temp sensor tells the gauge what the temp should be for the gauge on on the dash.
Yes that is the ect. The coolant temp sensor has a black and a dark green wire running to it. Do you have a digital volt meter?
What would you say the temp of the engine is right now?
What I need you to do is go out and unplug the sensor, and with your meter set to ohms, see what the reading is, then warm the car up and see what it is when the temp gets up around the normal range please.
I need you to test the sensor itself not the wires and the sensor needs to be left unplugged.
The ect does not go to the gauge. The gauge has its own sensor. If the ect is working correctly according to a scan tool, then the drivers for the fans in the ecm must be bad. This would means that you need to replace the ecm. The ecm has three sets of drivers in it for the fans. One for when the ac is on, the low and the high. It is possible that when you unplug the ect that the ecm is using the ac drivers to turn the fans on.
If the relays where bad, the fans where bad, then the fans would not come on when you unplug the ect. You said the ect readings where good when it was connected to a scanner So the only thing left will be the ecm itself.
Then please go do the test I asked you to do.
Your ect has a yellow and a black wire, the engine coolant temp sensor has a dark green and a black wire. If you have done the test I asked for, what where the readings?
Hello my name is ***** ***** I can help.
Does your scan tool show live data.
Need to know what the PCM coolant temp is. The dash gauge it self my be reading higher than the pcm temp
The fans wont come on until 230
Did you understand what I was asking for?
Please let me know if you need more help?
I know you are saying hot temperature. Can you tell the degrees?
If you turn on the A/C do the fans come on at low speed?
When you unplug the sensor can you tell if the fans are on high?
Does your scan tool control the fan speeds?
So when the temp gauge on the dash reads 260. The PCM also shows 260.
Is that correct?
The fans do not come on?
On the scan tool does it show. Do you have any live data that shows fan relay request ON/OFF
The fact you can control the fans. Tells me the PCM can turn on the relays.
I agree that the computers are reliable.
You have all the right input data and outputs. But the PCM wont turn on the relays itself.
Is this the original PCM?
Can you scan tool read the VIN# ***** the PCM? If so make sure it matches the car.
Thank you for getting back with me.
If you still need more help let me know.
If you can take a moment and rate my service.