Lexus IS Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1 (Edited)
The problem:
Speedometer, odometer and mpg gauge do not work. Everything else works on the cluster.

The story:
2001 is300 manual swapped w55.
Auto ecu (no vss connected because auto harness).
When I bought the car the speedometer worked fine with all of these lights- solid "brake", flashing "trac", solid "abs".

Randomly the speedometer stopped working last winter. I knew I had a bad front abs wheel sensor so I replaced the abs sensor. After the new sensor all of the lights went off. No abs light, no trac light, and no brake light on the cluster.
Speedometer worked fine for maybe 2 months. Then stopped working again.

Today I tried the "Skid ecu to speedometer rewire". (Which basically bypasses the existing stock auto harness to its same exact destination)
Explained in this thread
http://my.is/forums/f114/how-abs-speedo-rewire-v160-swapped-iss-02-5spds-412759/#/topics/412759

I also jumped pin A15 (cluster) to "MPX-B" fuse (pass kick panel) just to ensure good continuity.

All other fuses in every kick panel and under every fuse box are good.
After looking through the schematic I have no idea, can anybody help me out here please?
 

·
Registered
Joined
·
5,270 Posts
How about hooking it back up the way it was? The 01 and 02+ clusters are different. The speed pulses for the ECU in 02+ come off the cluster. In 01, they come directly from the transmission.

Speed pulses to ECU:

02+
Transmission/Abs -> cluster ->ECU

01
Transmission->ECU

The speed pulses for display speed on the 01 is
01
ABS->Cluster

02
Transmission->Cluster - Manual
Abs->Cluster - Automatic


So, in 01, the ECU gets the speed off the transmission and the cluster gets speed off the ABS.

Are you using an Automatic ECU with this? If so, you're probably not making full power.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #3
I tried tapping the signal for the cluster directly from the ABS/skid computer. I'm confused why that wouldn't give the cluster the correct signal.

Yea I realized how much slower the car feels recently with the auto ecu! Funny you say that, something about how it retards the timing because of the cels I think I read somewhere.
 

·
Registered
Joined
·
5,270 Posts
I'll try connecting the w55 speed sensor to the auto harness. Maybe it really needs that signal to the ecu
In your shoes this is what I'd do. It's what I did with my manual swap. Of course in my case the calibration was off. If I left it manual, I was going to install a speed conditioner between the tranny and the ECU which would make the ECU reported speed the same as the dash reported speed.

You might find you need to do this. You can check the ECU reported speed with the OBD2 scanner. Don't be surprised if it's quite different than the speed reported on the cluster.

I tried tapping the signal for the cluster directly from the ABS/skid computer. I'm confused why that wouldn't give the cluster the correct signal.

Yea I realized how much slower the car feels recently with the auto ecu! Funny you say that, something about how it retards the timing because of the cels I think I read somewhere.
I don't think a manual swap into an 01 can be made to work properly unless you also switch in a manual ECU. Supposedly some Russians sell a box that helps simulate the transmission but the level of effort to get all that working was beyond my interest level. I ended up just switching it back to auto and selling off my swap. I had a transmission simulator that kept the CEL's off but, the Auto-ECU is looking for 2 speed sensors, one on the tail-shaft and one from the torque converter. Without simulating those, I think you'll have problems with low power mode.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #6
You might find you need to do this. You can check the ECU reported speed with the OBD2 scanner. Don't be surprised if it's quite different than the speed reported on the cluster.
^Good info! I'll have to see if I can find anyone with a really great obd2 scanner I can use.

I don't think a manual swap into an 01 can be made to work properly unless you also switch in a manual ECU.
Funny you mention that. Because I went from hell and back trying to make a manual 2005 ecu work on this auto 2001 harness. I had tweak'd performance make me a patch harness. Too many obstacles so I abonded ship also.

Without simulating those, I think you'll have problems with low power mode.
Yea it feels like lag without a turbo not fun ha. But I'll just deal with it for now, mostly just want to get the car to a decent dd status again.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #7
Started my "back to start" backtracking and I know the 02+ doesn't read speed signal the same way as my 2001 but I figured I'd connect the speed sensor anyway. Is it needed for my 2001?

I noticed the 2001 auto harness (on the car) speed sensor is for a 2 pin plug.
W55 speed sensor in the trans looks like a 3 pin plug?

Also tested my front abs sensors.
Driver front abs sensor= 1667-17xx ohms when spinning.
Passenger front abs sensor= 1690-17xx ohms spinning.
So it's safe to say the abs sensors are good?
 

·
Registered
Joined
·
5,270 Posts
I noticed the 2001 auto harness (on the car) speed sensor is for a 2 pin plug.
W55 speed sensor in the trans looks like a 3 pin plug?
I'd have to look at the pinnout. For the AR-5, I changed the connector on the harness. The AR-5 drove the ECU properly. The reported speed was just wrong because the diff ratio and tire sizes were different. I wonder if you might need to find a 2 wire sensor?
 

·
Registered
Joined
·
18 Posts
Discussion Starter #9
Manual trans has 3 pins for the speed sensor.
1. A12 cluster connector (red w/ yellow stripe)
2. B1 cluster connector (red)
3. 10A GAUGE fuse (red w/ light blue stripe)

Automatic has 2
1. B2 skid ecu (red w/ yellow stripe)
2. ????
I couldn't find a diagram in the service manual explaining the 2 wires for the auto speed sensor. Just the 1 wire also labeled "A/T" in the attached picture.

With all those random bits of info, and using an automatic cluster, which combo would be best?
I'm guessing the auto speed sensor? Will the auto speed sensor fit in my w55 trans?
 

Attachments

·
Registered
Joined
·
3 Posts
https://www.youtube.com/watch?v=4uYo1dfH...
Not sure if this applies to your scenario, but This video explains the 3 simultaneous symptoms others have had and shows the process of how it’s fixed. Hope this helps everyone who may run into this issue.
3 issues are:
1. speedometer not moving
2. odometer digital display is blank
3. shifting is erratic while trying to accelerate
 
1 - 12 of 12 Posts
Top