When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Here is yet another thread on a broken speedometer. My situation seems a little different from the rest, so I decided a new thread was best, rather than bumping an old one. Plus, this is going to be a long post! There is no TL;DR section, so you've been warned.
My rig is a 1993 Pickup 4WD with 22RE engine and electronic (not cable) speedometer. A few months ago, my speedometer needle started dropping to zero intermittently before finally quitting completely. The odometer also quit. Since both the speedometer and odometer quit, it seemed the VSS might be faulty. My mechanic used a scope and verified that the VSS was producing a nice clean square wave signal and suggested that I replace the instrument cluster.
New (used) clusters are selling for over $200 on ebay, and unfortunately I can't afford that right now. I've checked one local junk yard, but the poor pickup there was stripped clean. So, I started doing more testing to see if there is anything I could do to fix it. Here is what I've done:
Pulled the VSS, connected it to hot and ground using little jumper cables with alligator clips, and probed the signal and ground wires with my multimeter. I got about 11 volts. Turning the plastic gear slightly, it dropped to about 0.65 volts. Turning it some more, back to 11 volts. This seemed to confirm my mechanic's results.
Checked the continuity of the signal and ground wires between the cluster and a well-hidden wiring harness behind my ECU. They were fine. I then checked continuity from that harness to the connector on the VSS itself. Again, all was well. I also checked continuity from the cluster all the way to the VSS, in case that hidden harness had a bad connection. Everything was good. A couple ohms of resistance (okay, I think??).
Checked the voltage between signal and ground on the connectors that clip into the back of the cluster. I can provide pictures and pin numbers if anyone is interested. With the cluster disconnected and the key in the on position, I read about 10.7 volts. With the cluster connected, I read only 2.65 volts. I'm assuming this drop is due to the components in the gauge itself.
Checked continuity between points "A" and "B" on the back of the cluster as recommended in the manual I have. These are just hot and ground. There was continuity, but fairly high resistance (around 57 ohms iirc). Again, I think this is due to the circuit components in the gauge.
Removed the speedometer gauge and tore it apart completely. My brother has some soldering and electronic skills, so he re-melted most of the solder points for good measure and replaced a couple capacitors that seemed to be bulging a bit. That didn't work. So I tore the gauge down again and my brother saw that a tiny hair-thin wire (one of four) had broken off from its post. He soldered it in place, but this still did not fix the problem.
Finally, I decided to bench(seat) test the speedometer and VSS together in order to eliminate any possible wiring issues from the equation. This involved a bunch of jumper cables and alligator clips, and a MacGyver'ed cordless drill to spin the VSS gear. I'll be happy to explain exactly how I did this if it will be helpful. I (rather naively) used the wires connected to the cigarette lighter for my hot and ground. When I ran the drill, the gauge worked beautifully! The needle moved smoothly, and I was able to hold it at 20 mph easily.
I honestly don't know what to conclude at this point... I cleaned the contacts on the back of the cluster, so I'm pretty sure that's fine. The contacts on the VSS look fine. There is no corrosion anywhere that I can see. The ECU is throwing code 42, which I would expect since the speedometer itself provides the ECU with a speed signal.
Before I scrape together the cash for a new cluster, or even a new VSS, does anyone know why my bench test worked when nothing else did? The only difference that I can see is a little bit more voltage in the bench test. Is the speedometer really that sensitive, or am I missing something?
You have the classic symptoms of a failing VSS1. Dropping to zero and popping up, then longer and longer, until.... it stays at zero until you do a bench test. Or it can smell a mechanic.
The sensor is an amplified hall-effect sensor. There is a seal around the shaft to keep ATF out of the sensor itself; someone on this list reported success cleaning the sensor (inside). I don't know if the seal can be realistically replaced.
Holy cow! I have no idea if any of these are any good, but for the price you can't afford to not try one. There is slight variation in these sensors by model, but they vary enough that you can tell if the picture matches yours.
Interesting! Thank you for the information and the links. It's amazing how cheap those sensors are, compared to what I've seen on the usual parts sites. I just hadn't done the proper research since I was so fixated on the cluster.
I will definitely buy a new sensor (or two) and keep you posted.
I ordered a sensor off ebay and it came today. It is identical to mine, except I found out it has two more gear teeth (20 vs 18). I decided to just swap the gears, since mine was fine. So far, it works like a charm! The speedometer and odometer work great now. I've only driven it about 15 miles this evening, so we'll see how it does with a long commute tomorrow.
The quality is okay, but the metal closest to the gear is pitted and uneven, which can't be seen in the photos on ebay. I'm certainly not complaining, though. $28 total is pretty sweet.
Now I just need to tear apart the old one and figure out how it works. I guess I should clear out that pesky code 42 from the ECU, too.
Thanks a ton for your help, scope103! You saved me a lot of time, money, and energy.
After another 120 miles, it is still working great.
Here's a nice summary for the search engines:
If you have a 1993 Toyota Pickup 4WD 22RE DLX Standard Cab with W56 transmission and your speedometer is not working or is intermittent, you may need a new VSS (speed sensor) with a gear that has 18 teeth. Before buying a new sensor, check the larger of the two numbers stamped on your existing gear and go with that.
I experienced this same exact problem with the electronic speedometer on my 1994 4x4 Toyota PU.....speedometer intermittentenly worked and just got worse and worse until it barely ever worked at all. I searched every forum and thread that I could but couldn't find an actual solution that had worked. Most said to change the speed sensor unit on the trans but seemed those that did that just wasted their money as it didn't work except in a case or two. So, I decided to take things into my own hands. I removed my instrument cluster, then I split the plastic cover in half at the seam and removed the mother board with the guages and speedo attached. I then removed the speedometer itself from the mother board (4 philips screws on the backside of the mother board) and pulled the speedo out which has its own board on the back of it. I then took an old toothbrush and sprayed the bristles with WD40 and proceeded to scrub the back of the speedo board with the WD'd bristles. I removed any crud that was there and sort of just scrubbed and polished all of the solder connections on the back of the board. Then I wiped it down as best as I could with a cloth. I put speedo back on the mother board and then the cluster back in the plastic case and reinstalled it all into the dash and buttoned everything back up figuring it was either going to work or not. Upon completionl, I started the truck up and drove off down the road and WAH-LAH!...the speedo worked perfectly and, it has continued to do so since. In that I already had the toothbrush and the WD40, my cost for this fix was zero $!!! I know this will sound hokey to some of you but this is not a joke and if you are having the intermittent speedo issue, I implore you to try this process on your cluster and see if it works for you.,,,I mean....what have you got to lose. Hope this works as well for you as it did for me.
i have a 1993 Toyota Pickup v6-auto…same issue of speedometer speed working then not working. I replaced my VSS2 on my transmission (both sensor and Gear). This did not work. My question to brotherbud…was your problem just the speed not working or did it affect your transmission also (or do you have a stick)?….Thanks for any reply.
VSS2 controls the shifting, and is on the transmission. VSS1 controls the speedometer, and is in the back of the transfer case. (You wouldn't get correct speed in 4-Lo if you picked the rpms before the transfer case.)
Yes, you are correct. I replaced VSS1 (with 20 tooth gear). The speedometer is acting up as shown on this thread. But it is also affecting the shifting of the transmission. So I assume since both VSS1 and VSS2 are wired to the ECM they both affect the shifting of gears?
03-06-2016, 05:19 PM
