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Hey guys, I'm getting c1226 (RF excessive wheel speed variation and c1233 (RF wheel speed open circuit) when I exceed around 5k RPMS. I tested the ABS sensor on the hub and get AC voltage when I spin the wheel, so as far as I know that tests good. I teat DC volts on the connector and then harness connectorb just behind it and get 9.4 on both. I started the car for gee whizz and same values. Should that be 12 volts? If not, what's my next step? Any assistance would be appreciated.
Wheel speed sensors produce their own AC voltage...no 12 volt reference...if you are getting an "open circuit" I'd check the connector at both ends of the harness...you can try spinning the wheel and shake the wiring down...you can use the 5 volt dc bias voltage too without having to spin the wheel..probably at 5K you have a lot of vibration going on down there at the tire...."sometimes" a lot of alternator AC ripple can cause these wheel speed sensor to whig out...a buddy of mine on the Forum's wife was saying her Tahoe was getting WSS DTC's...I had him check the AC ripple and it was over 1 volt I believe and the alternator was extremely HOT...you can check that just for the heck of it...with your multimeter set on AC put the leads across the battery terminals...use a low voltage setting and raise the RPM...anything over .5 volts is bad !!...good luck !!...oh, on my 2001 the sensor should ohm out from 850-1350 ohms !!...don't understand what you were trying to say about the 9.4 and the harness behind it ???????
Wheel speed sensors produce their own AC voltage...no 12 volt reference...if you are getting an "open circuit" I'd check the connector at both ends of the harness...you can try spinning the wheel and shake the wiring down...probably at 5K you have a lot of vibration going on down there at the tire...."sometimes" a lot of alternator AC ripple can cause these wheel speed sensor to whig out...a buddy of mine on the Forum's wife was saying her Tahoe was getting WSS DTC's...I had him check the AC ripple and it was over 1 volt I believe and the alternator was extremely HOT...you can check that just for the heck of it...with your multimeter set on AC put the leads across the battery terminals...use a low voltage setting and raise the RPM...anything over .5 volts is bad !!...good luck !!...oh, on my 2001 the sensor should ohm out from 850-1350 ohms !!...don't understand what you were trying to say about the 9.4 and the harness behind it ???????
C5 Diag thank you for your reply! To clarify, there is that segment that connects to the WSS, then runs back to a connector mounted to the cradle. I'll call that "cable A". I tested volts DC on both that cable A and the connector it connects to, assuming that if I got the same value, that segment is good. That value was 9.4 volts. Is your diagram saying there is ANOTHER segment? I am not wiring diagram savvy.
I'm aware the WSS itself doesnt have a 12V output, but I thought the harness would be providing 12v to it.
When you say "low setting" you mean like 2000m AC? And if I get above a .5v it's an alternator issue?? thanks again for your time.
The connector closest to the harness is one and the other is 6-8 inches upstream of that...I think that is the one you are referring to as being on the cradle...from there it is a straight shot to the EBCM..yes, like I said as the wheel spins the sensor is providing AC voltage to the EBCM where all the magic happens...the harness side signal wire has a 5 volt "bias" voltage key ON engine off !!!.. that comes from the EBCM...see the picture...the other wire is a low reference (ground)
at the top of the pic the conduit was heat rotted and didnt have any insulation, so I put new conduit and heat tape. I also swapped the cables from the WSS to the harness on both sides to see if the error moved. After the test drive c1226 went away, but c1233 (RF open circuit) remains. So it isnt that cable. I'm gonna try to follow those sensor testing guidelines, I just have little experience with testing OHMs.
I've researched and fixed dozens of C5s with this issue, including my 98 and 02 Z. Most of the time, its an issue with the WSS wiring harness connector female pins. For what ever reason, GM picked crappy pins and for no reason other than to make money, they SPREAD APART all by them selves. When the female pin/s spreads apart, it makes crappy connections with the male pins and you get the errors that you are seeing.. The only real way to be proof positive that the pins are really bad is to conduct a male pin PUSH /PULL test. Insert a male pin into the female pins and when you insert and extract the pin, there should be a firm grip on the male pin. When you have a bad female pin, it can literally just fall out
There are TWO female wiring harness connectors on each wheel assy. One that the jumper harness connects to on the frame inside the wheel well and the other is on the end of the jumper harness that connects to the HUB Assy pig tail.
You can attempt to bend the female pin back to a better grip, replace the bad connector with a replacement pigtail connector or solder/crimp on a new pin.
Thanks for the input Bill, I have a new female connector so I'll pry on the pins a bit, dab a little dialectic grease on there, and give her another try. I'll swap the connector if that doesnt work.
I've researched and fixed dozens of C5s with this issue, including my 98 and 02 Z. Most of the time, its an issue with the WSS wiring harness connector female pins. For what ever reason, GM picked crappy pins and for no reason other than to make money, they SPREAD APART all by them selves. When the female pin/s spreads apart, it makes crappy connections with the male pins and you get the errors that you are seeing.. The only real way to be proof positive that the pins are really bad is to conduct a male pin PUSH /PULL test. Insert a male pin into the female pins and when you insert and extract the pin, there should be a firm grip on the male pin. When you have a bad female pin, it can literally just fall out
There are TWO female wiring harness connectors on each wheel assy. One that the jumper harness connects to on the frame inside the wheel well and the other is on the end of the jumper harness that connects to the HUB Assy pig tail.
You can attempt to bend the female pin back to a better grip, replace the bad connector with a replacement pigtail connector or solder/crimp on a new pin.
Well after prying a bit, I feel more of a "purchase" when I connect them. But now when I turn the power on I get a check engine light, and upon starting, the TCS and ABS are there immediately. Prior to this, I had to go out and drive around for them to pop up.
I rechecked and reseated the connectors, no bent pins. Code is still c1233. the only thing I know to do is replace that female connector coming off the main harness....
Last edited by Summiz; Jul 31, 2019 at 02:05 PM.
Reason: elaborating
Thanks for the input Bill, I have a new female connector so I'll pry on the pins a bit, dab a little dialectic grease on there, and give her another try. I'll swap the connector if that doesnt work.
Dielectric grease doesn't improve the conductivity of the connection but actually makes it worse...it's only used to keep out moisture and prevent corrosion !!...I use this stuff !!
at the top of the pic the conduit was heat rotted and didnt have any insulation, so I put new conduit and heat tape. I also swapped the cables from the WSS to the harness on both sides to see if the error moved. After the test drive c1226 went away, but c1233 (RF open circuit) remains. So it isnt that cable. I'm gonna try to follow those sensor testing guidelines, I just have little experience with testing OHMs.
Dielectric grease doesn't improve the conductivity of the connection but actually makes it worse...it's only used to keep out moisture and prevent corrosion !!...I use this stuff !!
well ****... alright I'll do my best to swab it off and try again. Thanks for the tip.
Last edited by Summiz; Jul 31, 2019 at 04:50 PM.
Reason: correction
well ****... alright I'll do my best to swab it off and try again. Thanks for the tip.
Also I see members using dielectric grease on their spark plug boots at the plug and coil pack...gotta be careful where that stuff goes...you may start getting misfires !!...like I said previously you have to shake that wiring down to find something...Bill mentioned that also !!...great find on the wiring...the wiring in these cars are getting old and brittle and it's not going to be getting better down the road !!...were you showing a 9.4 bias dc voltage like I showed in my picture ??
I CRINGED when you said that you used Dielectric grease inside the connector. Get that stuff out and follows C5 Diags advice..
Bill
So I replaced the female connector on the subframe and cleaned the contacts. I start it, light are not illuminated, so I drive around for a while, putting it through its paces. No TCS or ABS the whole time so I am feeling good about it. Then I'm just cruising home and the lights come back. I'm going to replace that second female connector and I'm praying it works.
Since electrical gremlins are now starting to appear it may be a good idea to pick up one of these terminal cleaning kits...and Deoxit is another good contact "enhancer"...if all the contacts are cleaned and or replaced you may just have a broken wire somewhere in that harness !!
Since electrical gremlins are now starting to appear it may be a good idea to pick up one of these terminal cleaning kits...and Deoxit is another good contact "enhancer"...if all the contacts are cleaned and or replaced you may just have a broken wire somewhere in that harness !!
ABS and TCS
