You should be able to turn the speed sensor by hand and get some kind of electrical output.

 

I assume you replaced the gear driven #1 VSS located on the transaxle case. Did the replacement come with a new gear drive? They used to be sold separately? Check for broken teeth on the gear drive if it's the original. Check the hole for debris such as broken o-ring and circlip pieces.

Yes, the VSS that I replaced is the one on top of transaxle, holds by one bolt with 2 wire pin. What kind gear drive you are reffering to?

I had car taken to dealer today and they checked and said I need new cluster that comes with vehicle speeds sensor. I told them that I have tried to replace VSS and no help and that there is no signal to VSS on tranny. They said that there is another VSS on cluster. Are they telling truth? I don't know much about Toyota's only VW. Dealer wants $755.00 for cluster with labor.

I can get used cluster with same mileage for $125.00 but don't know if I would have to get it programmed or not.

 

The VSS detects wheel speed and sends the signals to the ABS ECU. The ABS ECU converts it to a 4 pulse signal and sends it to the instument cluster. The cluster then converts it to a more precise signal then outputs it to the ECM. So its not really that theres another sensor in the cluster, its just that the cluster has a role in relaying the speed signal to the ECM. I have yet to see a toyota instument cluster go bad like this, but i suppose it is possible. As I have never replaced one im not sure if they have to be reprogramed, but my guess is it probably would have to be.

 

losha64, I'm sorry for the confusion.
The A541E had 2 vss's (1 gear drive, 1 direct clutch speed sensor)until the 2000 Avalon was introduced. In 2000 the Avalon dropped the gear drive and kept the direct clutch speed sensor. It operates as ShawnM describes "converting pulses to speedometer readings".

A simple test of the speed sensor is to remove it and test the resistance (560-680 ohms).
Then test voltage by putting a magnet close to the tip up down or side to side. You should see low voltages generated.

I plugged a new cluster in a'99 without problem. The odometer read 0's because the cluster was new.

You may want to do the twist/push/and pull of the wiring and connectors including the cluster wiring.

Good Luck!

 

Thank you guys for quick reply.

(ShawnMThe VSS detects wheel speed and sends the signals to the ABS ECU. The ABS ECU converts it to a 4 pulse signal and sends it to the instument cluster. The cluster then converts it to a more precise signal then outputs it to the ECM. So its not really that theres another sensor in the cluster, its just that the cluster has a role in relaying the speed signal to the ECM. I have yet to see a toyota instument cluster go bad like this, but i suppose it is possible. As I have never replaced one im not sure if they have to be reprogramed, but my guess is it probably would have to be.)

Yes, I understand that how it works. One think I don't understand is what VSS sensor the dealer was talking about in cluster? Thats what doesn't make sense to me.

(csaxonlosha64, I'm sorry for the confusion.
The A541E had 2 vss's (1 gear drive, 1 direct clutch speed sensor)until the 2000 Avalon was introduced. In 2000 the Avalon dropped the gear drive and kept the direct clutch speed sensor. It operates as ShawnM describes "converting pulses to speedometer readings".

A simple test of the speed sensor is to remove it and test the resistance (560-680 ohms).
Then test voltage by putting a magnet close to the tip up down or side to side. You should see low voltages generated.

I plugged a new cluster in a'99 without problem. The odometer read 0's because the cluster was new.

You may want to do the twist/push/and pull of the wiring and connectors including the cluster wiring.

Good Luck!)

Thats what they said that the VSS that I replaced was for drive clutch not for speedometer. But when I was getting Vehicle Speed Sensor at dealer parts service there was only to options Wheel Speed Sensor (WSS) or Vehicle Speed Sensor (VSS) the one I got was VSS and the guy at parts even printed out where it exactly goes, on top of transaxle strait down by starter.

I'm having hard time believing what dealer is telling me.

 

CEL, ABS, BRAKE, dead speedo

I have a 2002 Avalon. First I had engine light on with evap emission codes. Got it fixed - guy said it was a broken evap tube somewhere. Worked for some days and CEL came back. Didn't mind it for a time. Then one day, my wife (primary driver) started complaining that the car jerks alot sometimes. Never could see the problem until one day it happened to me and I realized that speedo was dead at the time of the jerking. I took out and cleaned the VSS after reading abit in forums like this one. Vehicle seemed to return to normal:clap:, but that didn't last long. Then I lost the speedo reading and ABS and brake lights are on all the time.

I have changed the VSS. No good. I have checked the wire harness for the VSS. Checks out good. All fuses look healthy. No idea how to test relays. BTW a few relays labeled ABS this and ABS that are not there, but that was not a problem before so shouldn't be now I hope.

I have changed the speedo (after reading about it in this thread) - didn't help. I am wondering whether the speedo is the thing I should have changed or it is the other panel (the one with the CEL on it) b'cos that seems to have more electronics on it than the speedo board - and if there's any processing of the speed signal, it might be here. Anyone have a clue?:headbang:

I did that jumper wire on the OBDII port as described in the haynes manual and the code that came up was 62 which talks of anti skid ECU. But I don't even thing my car has that. Because in the middle panel, there is no bulb for the anti skid light. more :headbang::headbang:.

Got back to my salvage guy and he allowed me to try the middle panel with odometer. Well, it seems this has something to do with mileage because I now saw the other vehicles miles. But still no speedo reading and ABS and BRAKE lights are still on.

I suppose the ABS ECU is next but the dealer quotes $476 on it. The salvage place wanted $75 for it but it does not look like mine too much. I am afraid to open the abs pump to take this out. the system under pressure? Will air bubbles mess it up?

I am really hoping its not the computer. And if it is, it would be strange because no other symptoms show... Help!!

 

I don't know if anyone is still reading this. Its been a while since I got to the bottom of this. Here's the low down in case it helps anyone.

I took car to dealer for the $50 check and they confirmed a bad BAS ECU. They wanted $1000 or so for just the part, and some about $400 in labor if I got a salvage one. Told them I'd think about it - NOT.

I got on car-part.com and found some people who had my actual part number. Picked it up and found a way to place it right next to the one in the car and moved the electrical harness onto the replacement part. The light went off - meaning some good communication to the computer. But since everyone wanted $$$ for replacing it, I bit the bulled and did it myself.

The only part that was a challenge to me really was bleeding the brake lines after having opened them in the middle and introduced air. I spent a week doing research on that - since I had never done it before and I would read about other cars where you have to turn the ABS pump to get all the stuff moving around. Finally had enough to believe the 02 avalon did not require special handling - just bleeds like an ABS-free car.

From there its outright boring. Disable power, open lines, remove old unit, install replacement, reconnect the lines, even had my wife help me with bleeding - at least the stepping on the pedal. Done.

That done, ABS light went off. But the speedo still wouldn't work. For this I nearly lost hope. Except I found techinfo.toyota.com which has detailed info to the tee. Followed up all the circuits for a week and still couldn't find anything. Then one day, I discovered that one of the mechanics that had been looking at the system had widened the connector in one junction box with their probe and therefore the signal was not passing that point. Squeezed it back and everything began working. Sigh! That one was close.

 

By the way, the VSS on top of the tranny is about tranny speed monitoring not wheel speed. If you have vehicle speed issues, check on the wheel speed sensors as I learnt the long and hard way. The wheel speed sensors at the wheels (one for each wheel with ABS) send their signals to the ABS ECU which after using them for its purposes, also computes what it thinks is the actual vehicle speed and sends it to the dash (speed and odometer) which pass it on to the ECU.

 

enenum: I'm late to this post, but I have the same problem you do. Changed all 4 wheel sensors, speedo still doesn't work. I also have the ABS light on. You say changing the BAS ECU fixed the ABS light. What is a BAS ECU? Could that be a typo for ABS ECU? If so, where is it?
Also, can you tell me which connector on which plug was loose, and where it is.
This car has been off the road for 5 years with this problem, and I'm about ready to tow it to the wrecking yard.
Thanks,
Ralphie