Fun with trouble codes
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Joined: Feb 2005
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From: Harrisburg, PA 86 Vert w/ 89 wheels
Now on to MAF and speed sensors....
help me troubleshoot?
Code 15 - Engine Coolant Temperature (ECT) sensor - possible circuit high or shorted sensor
Code 24 - Vehicle Speed Sensor (VSS) circuit
Code 34 - Manifold Absolute Pressure (MAP) sensor - circuit out of range voltage, low or Mass Air Flow (MAF) sensor circuit (gm/sec low)
Coolant Low light comes in and out. Coolant levels always check out fine.
Anti lock light is locked in.
Also have exhaust smoke issues. More white than grey and can be kinda excessive sometimes.
I know what the code 24 is since I sometimes lose my speedo, then get it back when i hit a pothole. How to fix it? Also does the code 24 also bring up the anti lock light?
Also if you are close to Harrisburg PA and you help me make these problems go away I have much beer to offer.
Code 15 - Engine Coolant Temperature (ECT) sensor - possible circuit high or shorted sensor
Code 24 - Vehicle Speed Sensor (VSS) circuit
Code 34 - Manifold Absolute Pressure (MAP) sensor - circuit out of range voltage, low or Mass Air Flow (MAF) sensor circuit (gm/sec low)
Coolant Low light comes in and out. Coolant levels always check out fine.
Anti lock light is locked in.
Also have exhaust smoke issues. More white than grey and can be kinda excessive sometimes.
I know what the code 24 is since I sometimes lose my speedo, then get it back when i hit a pothole. How to fix it? Also does the code 24 also bring up the anti lock light?
Also if you are close to Harrisburg PA and you help me make these problems go away I have much beer to offer.
Last edited by illinest; Jul 15, 2005 at 02:47 AM.
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Joined: Feb 2005
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From: Harrisburg, PA 86 Vert w/ 89 wheels
So, what if i ordered this
http://www.madvet.com/shop?frame=3.13.867 engine coolant temp sender
and this?
http://www.madvet.com/shop?frame=3.12.3808 MAF combo sensor power and burnoff
would I be hurting the relays if its actually the MAF thats bad? Says that if I replace the MAF I should probably replace the relays as well, and the code 15 seems to be pointing directly at the ECT so.....
come on help me out
http://www.madvet.com/shop?frame=3.13.867 engine coolant temp sender
and this?
http://www.madvet.com/shop?frame=3.12.3808 MAF combo sensor power and burnoff
would I be hurting the relays if its actually the MAF thats bad? Says that if I replace the MAF I should probably replace the relays as well, and the code 15 seems to be pointing directly at the ECT so.....
come on help me out
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
That looks like the right coolant temp sender.
You might see if Contemporary Corvette (link on my site) has a good used MAF for an '85 Vette (as I recall you have '89 wheels on an '85??).
Generally it's a good idea to replace the relay before doing the MAF but not with an '85. When I replaced the MAF in my '88 I did not replace either of the relays.
The VSS signal comes from the sensor on the LH rear of the tranny tail shaft housing via a Yel and a Ppl wire to the inst cluster. From the inst. cluster the VSS signal goes to the ECM. I would first check the connector at the tranny and the wires comming from it before replacing that sensor.
You might see if Contemporary Corvette (link on my site) has a good used MAF for an '85 Vette (as I recall you have '89 wheels on an '85??).
Generally it's a good idea to replace the relay before doing the MAF but not with an '85. When I replaced the MAF in my '88 I did not replace either of the relays.
The VSS signal comes from the sensor on the LH rear of the tranny tail shaft housing via a Yel and a Ppl wire to the inst cluster. From the inst. cluster the VSS signal goes to the ECM. I would first check the connector at the tranny and the wires comming from it before replacing that sensor.
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Joined: Feb 2005
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From: Harrisburg, PA 86 Vert w/ 89 wheels
an 86 actually.
this is the best price ive found so far, but it's aftermarket so im not ready to trust it until it's been okayed
http://www.madvet.com/shop?frame=3.12.5594
there is also an ebay for a brand new MAF but its for an 85 so im guessing that would present problems considering i have the aluminum heads?
I'll get right to work on finding a lift to look at that VSS, hopefully this one is easy.
Thanks for the help 65Z01.
also found a rebuilt one here for much cheaper. opinions?
http://store.yahoo.com/dpstore/afmarw3.html
and the beginning of a theory, says that if the MAF isnt operating then the engine will alternate between lean and rich conditions. Sounds very similar to the way my engine smokes real bad and then dont smoke much at all? Could my exhaust smoke episodes be caused by rich fuel cycles caused by a faulty MAF?
holy moley this is fun. I wish it were light out so i could inspect the MAF closer.
this is the best price ive found so far, but it's aftermarket so im not ready to trust it until it's been okayed
http://www.madvet.com/shop?frame=3.12.5594
there is also an ebay for a brand new MAF but its for an 85 so im guessing that would present problems considering i have the aluminum heads?
I'll get right to work on finding a lift to look at that VSS, hopefully this one is easy.
Thanks for the help 65Z01.
also found a rebuilt one here for much cheaper. opinions?
http://store.yahoo.com/dpstore/afmarw3.html
and the beginning of a theory, says that if the MAF isnt operating then the engine will alternate between lean and rich conditions. Sounds very similar to the way my engine smokes real bad and then dont smoke much at all? Could my exhaust smoke episodes be caused by rich fuel cycles caused by a faulty MAF?
holy moley this is fun. I wish it were light out so i could inspect the MAF closer.
Last edited by illinest; Jul 15, 2005 at 02:18 AM.
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Joined: Feb 2005
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From: Harrisburg, PA 86 Vert w/ 89 wheels
new update, pulled the MAF, checked it over, I see the wire filaments inside and they all LOOK fine. (shouldnt that mean it's probably fine?)
also when I disconnected and reconnected I managed to get another trouble code
33 - MAP sensor - signal voltage out of range, high or mass air flow sensor - signal voltage out of range, probably high
this means it has to be MAF doesnt it....
There is a tiny pinhole on the bottom of the accordion tubing that connects maf to throttle body. I cant SEE the pinhole (its so small) but i can see that the plastic is bent in where it shouldnt be and experience tells me to expect a puncture.
also when I disconnected and reconnected I managed to get another trouble code
33 - MAP sensor - signal voltage out of range, high or mass air flow sensor - signal voltage out of range, probably high
this means it has to be MAF doesnt it....
There is a tiny pinhole on the bottom of the accordion tubing that connects maf to throttle body. I cant SEE the pinhole (its so small) but i can see that the plastic is bent in where it shouldnt be and experience tells me to expect a puncture.
Drifting
Joined: Mar 2005
Posts: 1,923
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From: GA
Originally Posted by illinest
new update, pulled the MAF, checked it over, I see the wire filaments inside and they all LOOK fine. (shouldnt that mean it's probably fine?)
also when I disconnected and reconnected I managed to get another trouble code
33 - MAP sensor - signal voltage out of range, high or mass air flow sensor - signal voltage out of range, probably high
this means it has to be MAF doesnt it....
There is a tiny pinhole on the bottom of the accordion tubing that connects maf to throttle body. I cant SEE the pinhole (its so small) but i can see that the plastic is bent in where it shouldnt be and experience tells me to expect a puncture.
also when I disconnected and reconnected I managed to get another trouble code
33 - MAP sensor - signal voltage out of range, high or mass air flow sensor - signal voltage out of range, probably high
this means it has to be MAF doesnt it....
There is a tiny pinhole on the bottom of the accordion tubing that connects maf to throttle body. I cant SEE the pinhole (its so small) but i can see that the plastic is bent in where it shouldnt be and experience tells me to expect a puncture.
And fix that pin hole in the duct the very first thing.
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From: Harrisburg, PA 86 Vert w/ 89 wheels
Originally Posted by Morley
first inspect the connector going to the MAF sensor, look for bent pins on the MAF and on theharness side look for female pins that have been spread apart. Next, replace the MAF power and burn off relays as a pair. After that start and run the car unil it reaches closed loop, while it is running gently rap on the MAF housing with a screwdriver handle and see if the idle changes. If the idle changes while doing the previous step...MAF sensor time, and yes, you can use the 85 MAF sensor, they atually seem to work better with the 165 ECM's than the MAF's made specifically for the 165's.
And fix that pin hole in the duct the very first thing.
And fix that pin hole in the duct the very first thing.
That's ridiculous.
I WILL take the car to the dealer to get the ECT replaced. I can't tell how to get at it easily so I'm just gonna let them charge me .8 hours worth of labor at 74 per. I can get the part for 8 dollars.
The VSS problem seems to be intermittent, will it be possible to just clear the code right before the inspection and then live with the occasional loss of speed indication? I'll be in a better position to get this fixed after Christmas so I'm trying to just get it legal first.
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Thread Starter
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Joined: Feb 2005
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From: Harrisburg, PA 86 Vert w/ 89 wheels
*UPDATE!!!*
relays SOLVED THE MAF CODES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!
im taking it in for the ECT, and the VSS cleared when i disconnected the battery so this tuesday will be the FIRST time since i got the Vette last year that all trouble codes will be cleared.
i am sooooo stoked. this is my first serious attempt at fixing a car myself.
relays SOLVED THE MAF CODES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!
im taking it in for the ECT, and the VSS cleared when i disconnected the battery so this tuesday will be the FIRST time since i got the Vette last year that all trouble codes will be cleared.
i am sooooo stoked. this is my first serious attempt at fixing a car myself.
Burning Brakes
Joined: Mar 2003
Posts: 1,174
Likes: 6
From: NW MN
Originally Posted by illinest
*UPDATE!!!*
relays SOLVED THE MAF CODES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!
im taking it in for the ECT, and the VSS cleared when i disconnected the battery so this tuesday will be the FIRST time since i got the Vette last year that all trouble codes will be cleared.
i am sooooo stoked. this is my first serious attempt at fixing a car myself.
relays SOLVED THE MAF CODES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!
im taking it in for the ECT, and the VSS cleared when i disconnected the battery so this tuesday will be the FIRST time since i got the Vette last year that all trouble codes will be cleared.
i am sooooo stoked. this is my first serious attempt at fixing a car myself.
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Joined: Feb 2005
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From: Harrisburg, PA 86 Vert w/ 89 wheels
Originally Posted by 86Pacecar
Glad you got some of it fixed yourself. Actually the Coolant Temp sensor is very easy to do if you have a big enough socket. The code 15 is actually from the sendor being open or the wiring harness being bad and not reading the sensor. It is a very common part available at any auto parts dealer(GM used this sensor on many different vehicles). For the price I would get both the sensor and wiring harness as the harness will very likely be brittle from age and heat. Good Luck!
I'd like to do the coolant sensor but i cant figure out exactly what it is...
:o
I know its supposed to be like, in front of the throttle body and I have some pictures of new ones but theres too much other ....
stuff
in the way. vacuum hoses? I dont know what that crap is.....
Drifting
Joined: Mar 2005
Posts: 1,923
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From: GA
Originally Posted by illinest
Thanks guys
I'd like to do the coolant sensor but i cant figure out exactly what it is...
:o
I know its supposed to be like, in front of the throttle body and I have some pictures of new ones but theres too much other ....
stuff
in the way. vacuum hoses? I dont know what that crap is.....
I'd like to do the coolant sensor but i cant figure out exactly what it is...
:o
I know its supposed to be like, in front of the throttle body and I have some pictures of new ones but theres too much other ....
stuff
in the way. vacuum hoses? I dont know what that crap is.....
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Yes, the coolant temp sensor is located below the TB in the front of the intake base. Remove the MAF and the bellows to the TB and it will be easier to see and access the sensor.
Drain out about 1 gal of coolant before you remove the sensor as it extends into the water jacket in the front of the intake base.
Drain out about 1 gal of coolant before you remove the sensor as it extends into the water jacket in the front of the intake base.
Thread Starter
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Joined: Feb 2005
Posts: 632
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From: Harrisburg, PA 86 Vert w/ 89 wheels
I just gotta say,
WOW.
I've never felt so much like a bad@ss as I did when I fired up my Vette today and saw that the check engine light is no longer on.
I did my own coolant temp sensor, it was a little more involved than anything ive ever attempted before, but I had no problems at all doing the replacement.
This is the first time I've ever attempted (and completed) a job that required me to take off unrelated parts to get at what I needed to fix.
The sensor works fine, but the connector is damaged and I think it still gets a little bit loose sometimes. Shoulda listened to 86pacecar.... ^_^
Still have a speed sensor fault to check out..... (tomorrow)
thanks for encouraging me to work on this my self, I probably saved myself 75 dollars.
WOW.
I've never felt so much like a bad@ss as I did when I fired up my Vette today and saw that the check engine light is no longer on.
I did my own coolant temp sensor, it was a little more involved than anything ive ever attempted before, but I had no problems at all doing the replacement.
This is the first time I've ever attempted (and completed) a job that required me to take off unrelated parts to get at what I needed to fix.
The sensor works fine, but the connector is damaged and I think it still gets a little bit loose sometimes. Shoulda listened to 86pacecar.... ^_^
Still have a speed sensor fault to check out..... (tomorrow)
thanks for encouraging me to work on this my self, I probably saved myself 75 dollars.