Noob Q: SES-knock sensor code and coolant related?
09-20-2011, 08:59 PM
#1
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Noob Q: SES-knock sensor code and coolant related? Hey, guys, so I bought my car with the low coolant light on. Previous owner said it was a sensor, and on the 2 hour drive back on the highway, temperatures were perfectly in the center of the gauge, car ran (still runs) like a champ. I took him at his word. When I made it back to my place, though, shortly after filling up with 93 octane Chevron, the Service Engine Soon light came on.
I put the car away in my garage for around 2 months or so while I dealt with a cabin rain leak, and in the process, found that the oil cap was somehow missing...
Replaced the oil cap, SES went away.
Cabin leak fixed, I took her to the road. Low coolant light still on, but, as before, no overheating, smooth-running. My coworker even commented how smooth it was (he's the one who pointed out some things, like the unreported accident damage, spot on, so I'm willing to take him at his word).
Well, that SES light came back. Got the code scanned, knock sensor. Reset, SES-light-free until the next morning, SES light on again, same code.
The Advance Auto tech pointed out it might be a coolant issue since the knock sensor is in the coolant line to sense frequencies in it.
So my questions: Does this make sense? Should I just try a coolant flush and try flushing out the sensors with water/some chemical? Should I go for replacing all the sensors? What's the next step/what would YOU do next?
(Would be great to get an answer by Friday because I'll have time to work on her then...)
I put the car away in my garage for around 2 months or so while I dealt with a cabin rain leak, and in the process, found that the oil cap was somehow missing...
Replaced the oil cap, SES went away.
Cabin leak fixed, I took her to the road. Low coolant light still on, but, as before, no overheating, smooth-running. My coworker even commented how smooth it was (he's the one who pointed out some things, like the unreported accident damage, spot on, so I'm willing to take him at his word).
Well, that SES light came back. Got the code scanned, knock sensor. Reset, SES-light-free until the next morning, SES light on again, same code.
The Advance Auto tech pointed out it might be a coolant issue since the knock sensor is in the coolant line to sense frequencies in it.
So my questions: Does this make sense? Should I just try a coolant flush and try flushing out the sensors with water/some chemical? Should I go for replacing all the sensors? What's the next step/what would YOU do next?
(Would be great to get an answer by Friday because I'll have time to work on her then...)
09-20-2011, 09:16 PM
#2
NO NO NO......the Advance Auto guy is a jackass....as usual.
The low coolant sensors in these cars go bad all the time. Its right under the radiator cap on the back. Its the square sensor. Replace the sensor or just unplug it to get the light to stay off. Mine has been unplugged for 10 years.
Frequencies in the coolant lines....hahahaha
Knock sensor is probably bad. There's two of them under the intake.....not sure if there's more.
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The low coolant sensors in these cars go bad all the time. Its right under the radiator cap on the back. Its the square sensor. Replace the sensor or just unplug it to get the light to stay off. Mine has been unplugged for 10 years.
Frequencies in the coolant lines....hahahaha
Knock sensor is probably bad. There's two of them under the intake.....not sure if there's more.
.
09-20-2011, 09:22 PM
#3
Funny ****....last week I stopped by to have Advance Auto scan my car to get the codes. I had a lean 02 sensor code.
I swear, he says:
"Come on inside, you need a new MAF meter, we usually stock them."
Another time I was asking if they sell the AC Delco factory brake pads....the guy says, "man you gotta get ceramic pads, you'll stop in half the distance."
Swear...................
.
I swear, he says:
"Come on inside, you need a new MAF meter, we usually stock them."
Another time I was asking if they sell the AC Delco factory brake pads....the guy says, "man you gotta get ceramic pads, you'll stop in half the distance."
Swear...................
.
09-20-2011, 10:13 PM
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Alright, so I'll have to buy a knock sensor (have 1 that came with the car for whatever reason ), coolant sensor (call me ****-I like it when my cars have everything working), anything else? I'm a complete newb at this-should I add a few improvements/upgrades while I'm at the knock sensors and coolant sensor? I am guessing coolant sensor replace will necessitate a flush?
Incidentally, I'm glad you posted. I came across your coolant flush guide a couple times searching-thanks for posting that up.
), coolant sensor (call me ****-I like it when my cars have everything working), anything else? I'm a complete newb at this-should I add a few improvements/upgrades while I'm at the knock sensors and coolant sensor? I am guessing coolant sensor replace will necessitate a flush?Incidentally, I'm glad you posted. I came across your coolant flush guide a couple times searching-thanks for posting that up.
09-20-2011, 10:44 PM
#5
Alright, so I'll have to buy a knock sensor (have 1 that came with the car for whatever reason ), coolant sensor (call me ****-I like it when my cars have everything working), anything else? I'm a complete newb at this-should I add a few improvements/upgrades while I'm at the knock sensors and coolant sensor? I am guessing coolant sensor replace will necessitate a flush?
Incidentally, I'm glad you posted. I came across your coolant flush guide a couple times searching-thanks for posting that up.
), coolant sensor (call me ****-I like it when my cars have everything working), anything else? I'm a complete newb at this-should I add a few improvements/upgrades while I'm at the knock sensors and coolant sensor? I am guessing coolant sensor replace will necessitate a flush?Incidentally, I'm glad you posted. I came across your coolant flush guide a couple times searching-thanks for posting that up.
No....when you take the metal clip off the sensor and pop it out you will lose some coolant.....just put the new sensor on and then open the radiator cap and top it off with water. Thats it.
I was just suggesting that a knock sensor might be bad. I would first ask in the PCM Diagnostics" section to see if that code comes up if a knock sensor fails or for some other reason.
You have to remove the intake.....there's really nothing to upgrade..performance wise. I would however, check your heater hoses that come off the water pump (two ports on the passenger side of the water pump) and lead back to the firewall where they attach to the heater core. They are much easier to replace with the intake off. Just check the hoses for softness or for any signs of bulging at the metal couplers and the water pump ports. You can buy used ones for around $50-$75 on ebay or other places...or just use $20.00 worth of heater hose and run the hose yourself. But if you run the hose yourself, you'll need to heat wrap them in the area where they run along where the exhaust manifold pipes are to keep the radiant heat off the rubber.
I just bypassed my heater hoses for now because they were just about to pop. I also replaced my coolant crossover hose with a piece of heater hose, it was mushy as hell.
Maybe replace the intake gaskets while you're in there too, they will cause vacuum leaks when they get old.
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09-23-2011, 02:49 PM
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Okay, well, it looks like the general consensus is just change the knock sensors and harness.
Caveats:
Use ACDelco sensors/harness only. (PN: 213-3521 and 12601822[ws6store was the only place I could find one])
Be VERY careful removing the intake, as the brake booster vacuum line can snap the oil pressure sending unit. (PN: D1818A)
After replacing the sensors/harness, have some RTV hi-temp sealant and seal everything down. Be careful to not let the sealant seal to the intake, or you'll probably break the sensor again if you remove the intake.
Anything else? If I don't get any responses, I guess we'll find out when I have to do the repair within the next week or so...
Caveats:
Use ACDelco sensors/harness only. (PN: 213-3521 and 12601822[ws6store was the only place I could find one])
Be VERY careful removing the intake, as the brake booster vacuum line can snap the oil pressure sending unit. (PN: D1818A)
After replacing the sensors/harness, have some RTV hi-temp sealant and seal everything down. Be careful to not let the sealant seal to the intake, or you'll probably break the sensor again if you remove the intake.
Anything else? If I don't get any responses, I guess we'll find out when I have to do the repair within the next week or so...
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10-07-2011, 09:17 PM
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Reporting back. I didn't damage the OPSU during the operation, but I did take a quick gander at it. It looks visually like the D1818A you can find from ACD, but I can't actually confirm it. The knock sensor replacement fixed the SES light. Didn't check coolant, though.
