Dead Speed Sensor?

[JZiggy]

Hey guys,

4-banger manual transmission here... I bought a new gear for the speedometer sensor when I changed tire sizes. The install went fine, but i had gotten the wrong tooth count so it made the inaccuracy worse. Got the right gear, swapped it in, and now my speed sensor appears to be dead. No speedometer or odometer action at all. After a few miles driving around it threw a code.

I took it back out and could not find anything wrong. Connection appears solid. I took the back of the sensor off and cleaned the contacts -- noticed nothing weird. Reinstalled and it is still dead.

I'm taking a change on this replacement el-cheapo speed sensor from Amazon.

Anyone have any tips for me? Is there a good way to test the speed sensor?

Also if you have a used OEM one you're looking to offload please let me know...

 

[Toyotayoda]

Does the old speed sensor work when installed? That would be your tell if the amazon sensor was bad. On rare occasion I've seen the gear in the transmission break, but try swapping in your old sensor and for drive first.

 

[JZiggy]

Sorry, should have been more clear: the Amazon speed sensor hasn't arrived yet. I have swapped out gears on my original SS only.

 

[JZiggy]

So I tried popping in the new speed sensor and clearing the code -- still have a dead speedometer.

Does anyone have some pages of the FSM that refer to the VSS for 1999 manual transmission? I think I need to do some real troubleshooting and I'm afraid my issue might be upstream of the sensor.

Thanks

 

[TheDurk]

So I tried popping in the new speed sensor and clearing the code -- still have a dead speedometer.

Does anyone have some pages of the FSM that refer to the VSS for 1999 manual transmission? I think I need to do some real troubleshooting and I'm afraid my issue might be upstream of the sensor.

Thanks

I have a '99 FSM (paper). Not much help in there, I'm afraid. It does inform that only the 4-bangers have a sensor on the transmission, 6 cyls like mine use the ABS wheel sensors in the rear.

There is no real troubleshooting info under P0500, other than that the sensor is good if the speedo works. (Thanks, Toyota.) If it does not, it tells you to check the speedo circuit.

The EWD says the signal hits the speedo at Pins 9 (purple/blue) and 1(green-blue) of the C28 plug, which is the blue one of the back of the speedo.

There is zippo in the W59 chapter except the torque: 9 ft-lbs.

The only good stuff is in the Combo Switch chapter in V2, where the FSM says to test the sensor, pull it, spin the shaft with key on, and you should have four pulses from 0 to 11 volts between the purple-blue and the green-blue for every turn. So I'd do that, and then, if successful, repeat at the speedo connection.

You can bench test the sensor by applying battery positive at Pin 1 (where the black-yellow goes) and negative at Pin 2 where the purple-blue goes, and then spin and read as above between Pin 2 and Pin 3 (where the green-blue goes).

If the connection is good, Toyota says only to replace the speedo.

Good luck.

 

[JZiggy]

I have a '99 FSM (paper). Not much help in there, I'm afraid. It does inform that only the 4-bangers have a sensor on the transmission, 6 cyls like mine use the ABS wheel sensors in the rear.

There is no real troubleshooting info under P0500, other than that the sensor is good if the speedo works. (Thanks, Toyota.) If it does not, it tells you to check the speedo circuit.

The EWD says the signal hits the speedo at Pins 9 (purple/blue) and 1(green-blue) of the C28 plug, which is the blue one of the back of the speedo.

There is zippo in the W59 chapter except the torque: 9 ft-lbs.

The only good stuff is in the Combo Switch chapter in V2, where the FSM says to test the sensor, pull it, spin the shaft with key on, and you should have four pulses from 0 to 11 volts between the purple-blue and the green-blue for every turn. So I'd do that, and then, if successful, repeat at the speedo connection.

You can bench test the sensor by applying battery positive at Pin 1 (where the black-yellow goes) and negative at Pin 2 where the purple-blue goes, and then spin and read as above between Pin 2 and Pin 3 (where the green-blue goes).

If the connection is good, Toyota says only to replace the speedo.

Good luck.

Durk, thanks man! That's exactly what I needed. I'll try to do the bench test tonight and report back.

The only causal link I have is that I pulled the sensor, replaced the speedo gear, and put it back and at that moment it quit working. When I replaced it that time it went in with a bit of a *thunk* due to the drag of the sealing o-ring. I had assumed that I had killed the sensor when that happened.

Maybe the connector is bad?

 

[JZiggy]

Welp, as I suspected it was something obvious.

The original 32T gear is about 1.13" in diameter, and so is the 33T. But the 30T I replaced it with was 1.03", so it simply wasn't meshing with the drive gear on the transfer. Doh!