HOrnbrod Posted October 27, 2013 Share Posted October 27, 2013 Before pulling the VSS, please check all the obvious first. Like continuity between the VSS connector and the ECU (there are a few connectors along the way), and continuity between the distance sensor and speedo. Also make sure the screws on the back of the speedo (and the other gauges while you are in there) are clean and tight against the flex-foil on the back of the cluster. Check to be sure the speedo gear is set correctly in it's proper tooth count slot so it will engage the distance sensor gear. These can all trigger a code 5 CEL fault too. When I bought my truck years ago the speedo wasn't working. I did all of the above first with no joy, then finally replaced the VSS in the AW4 as a last resort, which did fix the problem. It's pretty easy to get to on the 2WDs. http://gojeep.willyshotrod.com/HowtoSpeedoGears.htm Link to comment Share on other sites More sharing options...
carnuck Posted October 27, 2013 Share Posted October 27, 2013 VSS is on the tcase Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 27, 2013 Share Posted October 27, 2013 Can you read? I was referring to 2WD. Link to comment Share on other sites More sharing options...
carnuck Posted October 28, 2013 Share Posted October 28, 2013 Picture shows 4x4 trans and tcase. Speed sensor for the speedometer in on the tailstock of 2wd trans or tailstock of 4x4 tcase. The other speed sensor on the trans doesn't operate the speedometer. It's for the TCM. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 28, 2013 Share Posted October 28, 2013 No, the "other speed sensor on the trans", the VSS, feeds both the TCM and ECU on the HOs. The OP has an HO. And it does affect speedo operation. Link to comment Share on other sites More sharing options...
neohic Posted November 1, 2013 Author Share Posted November 1, 2013 :hmm: Continuity checks out. I'm now looking for a way to check the sensor on the trans and found this picture: ... but no other information to back it up. Any idea how to check this and what a reading should be? I checked the sensor of the t-case also and did get a reading from it. Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 1, 2013 Share Posted November 1, 2013 The best way (other than using the DRBIII scanner) is to check with an ohmeter across the connector pins while rotating the wheels (or the tranny). The meter should make/break continuously while the tranny is turning. But it's not always conclusive. Mine tested okay even though it was bad. Link to comment Share on other sites More sharing options...
ParadiseMJ Posted November 8, 2013 Share Posted November 8, 2013 :popcorn: Link to comment Share on other sites More sharing options...
neohic Posted November 8, 2013 Author Share Posted November 8, 2013 I know... I know... Haven't had much for time to crawl under the truck and take another look. Been cruising around and just keeping up with traffic. :roll: Link to comment Share on other sites More sharing options...
ParadiseMJ Posted November 8, 2013 Share Posted November 8, 2013 No pressure LOL I didn't want to horn in on your thread so I started another one, just asking my specific question. Actually I thought this was an old thread, I found it when I was searching. Watching this hoping we both get our problem sorted out. Thanks Link to comment Share on other sites More sharing options...
ParadiseMJ Posted November 9, 2013 Share Posted November 9, 2013 :hmm: Continuity checks out. I'm now looking for a way to check the sensor on the trans and found this picture: ... but no other information to back it up. Any idea how to check this and what a reading should be? I checked the sensor of the t-case also and did get a reading from it. "Speed Sensor Testing Test the sensor with an ohmmeter. Place the leads of the ohmmeter on the sensor connector. Rotate the output shaft of the transmission. The needle should deflect indicating the switch is opening/closing. as the rotor moves past the sensor (Fig. 40 [you posted Fig 40]). Replace the sensor if the ohmmeter does not display any kind of reading. If a digital ohmmeter is being used, the sensor should generate an ohmmeter reading each time the switch opend and closes." Link to comment Share on other sites More sharing options...
neohic Posted November 10, 2013 Author Share Posted November 10, 2013 "...If a digital ohmmeter is being used, the sensor should generate an ohmmeter reading each time the switch opens and closes." Crawled under the truck today and I'm really glad that I didn't go with the factory t-case shifter crap. This allowed me to get rid of the bracket that holds part of the factory stuff and get a better look at things. There it is! Unplugged it again to check for an ohm reading. I was really hoping that it wouldn't, but I got a reading. Don, I know you said that yours checked out but it turned out to be the problem... think I might be in the same boat? Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 10, 2013 Share Posted November 10, 2013 Yes, mine did check good with an ohmmeter. My meter has a switch position on the ohms scale that beeps when it senses continuity. I had it across the connector pins in this position, had the AW4 in neutral with the ignition key on, and rotated the tires by hand with the rear axle jacked up of the ground. It did beep as I turned the wheels. But this check I think is unreliable as turning the wheel by hand probably equates to a speed of .0009 MPH, and the speedo doesn't even register at that speed. Since our local Mom and Pop Jeep dealer didn't have a working DRBII scanner to do a proper check, I took a chance and replaced it. It's easy to get to on the 2WD tailpiece. Luckily the speedo started working again. Don't know if it will for you Ben. Are you sure the wiring checks good all the way back? Speedo mounting screws in the cluster good and tight? Link to comment Share on other sites More sharing options...
neohic Posted November 10, 2013 Author Share Posted November 10, 2013 ... Are you sure the wiring checks good all the way back? Speedo mounting screws in the cluster good and tight? I checked continuity from the sensors to the firewall. Screws in the cluster were all tight. I even took everything apart in there to clean the board. The thing about it is it worked June when I was swapping everything over: Truck hasn't been on the road more than 50 miles since then. It worked without the driveshaft in... haven't pulled it back out to recreate the day of the video. Worth it? Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 10, 2013 Share Posted November 10, 2013 ... Are you sure the wiring checks good all the way back? Speedo mounting screws in the cluster good and tight? I checked continuity from the sensors to the firewall. Screws in the cluster were all tight. I even took everything apart in there to clean the board. The thing about it is it worked June when I was swapping everything over: Truck hasn't been on the road more than 50 miles since then. It worked without the driveshaft in... haven't pulled it back out to recreate the day of the video. Worth it? I don't see how the drive shaft in or out will affect it since the rotor is still turning in the tranny and the VSS reed switch is still making and breaking. Have you tested this? I suppose you could stick in back in to recreate the original condition. Easier than changing out the VSS sensor.................. Link to comment Share on other sites More sharing options...
neohic Posted November 10, 2013 Author Share Posted November 10, 2013 I don't see how the drive shaft in or out will affect it since the rotor is still turning in the tranny and the VSS reed switch is still making and breaking. Have you tested this? I suppose you could stick in back in to recreate the original condition. Easier than changing out the VSS sensor.................. :hmm: Not sure what you're getting at here. I was referring to the rear driveshaft. Speedo hasn't worked since the rear shaft went in... probably just a coincidence though. I tested the sensor in the trans this morning. Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 10, 2013 Share Posted November 10, 2013 I don't see how the drive shaft in or out will affect it since the rotor is still turning in the tranny and the VSS reed switch is still making and breaking. Have you tested this? I suppose you could stick in back in to recreate the original condition. Easier than changing out the VSS sensor.................. :hmm: Not sure what you're getting at here. I was referring to the rear driveshaft. Speedo hasn't worked since the rear shaft went in... probably just a coincidence though. I tested the sensor in the trans this morning. Ah, okay - I read it wrong. Agree with the rear driveshft coincidence though. Just curious, how many electrical pins are on the adapter connector above the plastic speedometer calibration gear? This one: Link to comment Share on other sites More sharing options...
neohic Posted November 10, 2013 Author Share Posted November 10, 2013 ... Just curious, how many electrical pins are on the adapter connector above the plastic speedometer calibration gear?... Two. Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 11, 2013 Share Posted November 11, 2013 That's correct for only the 91s. ASSume the original 91 TCU is swapped in too? I'm fresh out of ideas Ben. Hate to have you go through all the work of changing the VSS and it doesn't solve the problem, but it looks like you covered everything else. Link to comment Share on other sites More sharing options...
neohic Posted November 11, 2013 Author Share Posted November 11, 2013 That's correct for only the 91s. ASSume the original 91 TCU is swapped in too? I'm fresh out of ideas Ben. Hate to have you go through all the work of changing the VSS and it doesn't solve the problem, but it looks like you covered everything else. All electronics were swapped over from a '91 including the TCU. Unfortunately, electrical is about the only thing I don't have an ample inventory of. If the sensor on the trans is the same from '87-'97, I'd just swap it out with another to see if it changes anything... that I don't have sitting around. Link to comment Share on other sites More sharing options...
neohic Posted November 11, 2013 Author Share Posted November 11, 2013 ... Just curious, how many electrical pins are on the adapter connector above the plastic speedometer calibration gear?... Two. Come to think of it, I didn't swap over the harness from the sensor on the trans to the firewall as it plugged right in. I did move over the harness from the sensor on the t-case to the firewall because it was missing when I got the donor. Any difference in there maybe? Originally, the truck was a 4cyl/4spd that Austin started swapping over to a 6cyl/auto with a '93 XJ. Every piece of wiring was moved over from the '91 to this truck except for the harness from the trans sensor to the firewall. :dunno: Link to comment Share on other sites More sharing options...
neohic Posted November 12, 2013 Author Share Posted November 12, 2013 I think I'm going to rattle the dice on a new sensor. :crossfingers: Anybody else have any ideas? Link to comment Share on other sites More sharing options...
neohic Posted March 14, 2014 Author Share Posted March 14, 2014 To the top!... but still not working. :wall: Jim was nice enough to send me a spare sensor and I found some time this afternoon to take a look at this again. Yup... been flying blind all winter long and I think it's about time to take care of this. Anyhow, I've been having a rough week already and all winter long I've been nursing a torn rotator cuff . Sounds like a perfect combination for everything just falling into place, right? So, I get the truck up in the air, crawl under it (getting dripped on, of course), and I get stuck with my arm between the floor pan the the t-case. I mean... REALLY stuck. Not even sure how I got where I did! I get out, get the retaining bolt out of the trans for the sensor and run into my next situation... getting the sensor out. I'm pulling and turning in this tiny, little space that I only have room for one hand (which leads me to getting my arm stuck again) and then it just pops. Great!.. or not. MOST of the sensor comes out, or rather is removed from the truck. It broke. The little friggin plastic piece cracks so that half of it is still in the trans... and it's cracked off INSIDE the trans. Long story short (already getting to be a long story?), I got the remainder of the sensor out with the help of a lag screw and the new sensor went in just fine... once I got my arm out anyway. :rant: Did it work? @#$% no! Why would it, right?! That'd just be too easy! Then I think back to the last time that I actually saw the speedometer move and the driveshaft wasn't in at that time. Why not? I pull the driveshaft and put it in gear with high hopes of seeing the speedometer spin... somehow. So now I think I'm back to square one. I put it all back together just wanting to go inside with my tail between my legs. The kind of week that its been I was really hoping for at least one small win. I gotta say it was a real journey trying to get that dumb thing changed out... but I digress. *POP!*... "Wait, what was that?" ... my trouble light that I forgot under the truck. :headpop: Any new suggestions? Can I bench test the gauge itself? Link to comment Share on other sites More sharing options...
jimoshel Posted March 14, 2014 Share Posted March 14, 2014 I didn't have that much trouble pulling the thing. Maybe you should try it my instead of the way you're going at it. With the tranny on the ground. Not jammed up into the underside of some truck. :doh: Link to comment Share on other sites More sharing options...
neohic Posted March 14, 2014 Author Share Posted March 14, 2014 Worth trying a different cluster all together? The truck has dummy lights and those work as far as I know. :hmm: Edit... Scratch that. Even if the speedometer wasn't working if there was something up in the cluster the cruise control would still work, correct? Link to comment Share on other sites More sharing options...
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