AutoZone possible causes:

• Faulty Thermostat
• Low coolent level
• ECT fault condition

I guess replacing the Thermostat sounds easiest and I suspect that since when I changed the water pump they recommended changing it and I said don't bother.

Its a V6.

Anyone know if thats the top hose or the bottom hose. I think its the bottom hose but I'm not 100%. There seems to be a sensor as well on the top hose...hopefully that is the one for the guage on the dash which says the motor is not overheating.

Anybody know where the ECT is on this engine so I can ohm that out as well?

 

ect sensor is on top of the engine on the main coolant tube. 2 pin connector. no need to ohm out, just replace it. 2 coolant sensors in that area. the sensor for the gauge is right next to it, and is a one pin connector. parts house or the dealer will ask you if its the sensor for the gauge or the pcm. you need the one for the pcm.

 

I added more coolent and the light went out....it hasn't come back on. My mechanic buddy so don't bother with the ECT...thats not the problem. He said it was a stuck thermostat and he said just because the light went out doesn't mean its fixed. He said go ahead and replace it.

He said its on the bottom hose and the on the top hose manifold there is a bleed screw to bleed the air out once you have replaced it.

 

Dang...he was right...the light came back on. Went back to Autozone and they said I actually had two errors. The second one was P0173 Fuel Trim Malfunction (Bank 2). Does this mean its still the thermostat....or if you get two errors are you suppose to combine the two in thinking?

I believe that is driver side, pre cat 02 sensor.

 

== I can confirm this> I had the same symptoms and changed the driver's side O2 sensor, the one that you can reach from underneath between firewall and engine...

My experience: After dealing with this error and erasing the code, it was "good" for one day, after that it threw code 505, idle problems: I don't know, may be coincidental, I had at least one vacuum leak, so I changed some vacuum lines and a vacuum nipple plug (I have the EGR blocked off with a plate...)

BTW: Does anybody know if a blocked-off EGR is bad/worse for the gas mileage??

have a good evening

 

Where was your vacuum leak?

 

Update on this issue....

I found that when they changed the radiator, they removed the coolent fan for ease of belt access. Unfortunately, they only used one screw to but the fan schroud back. Knock on wood...no light for a whole tank of gas during warm weather.

 

Hi fraknsmontero: Not to be sarcastic but why did you block off your EGR if you don't know whether it will help or hurt MGP?

Google EGR disconnect vs mileage and you will find many, hightly technical, discussions about this. But regardless of who you believe the difference can only be a few %. If you'd done a before and after test you could inform us.

But lord knows we have enough OBD problems with our trucks (reference your issues) so why mess with something that isn't broken? Your ECU is telling your EGR to open per the program and is not seeing the expected change in A/F ratio. So what does it do? I don't know, but maybe some of your CEL problems are related? I have 220K miles on my stock engine and the EGR has not ruined anything.

Further, your truck will never pass your CA smog test with such an obvious mod so are you planning on reversing things every two years? Again, why take a chance if there are no obvious benefits?

All IMHO, of course.