Warning lights abs brake vac and vac off plus no speed omete

[JohnBros]

I have been having this issue in my 1998 GS300 for several years. As I drive the lights will come on and speed o meter stops working until I got it off and restart. No other things seem to be happening. Car runs fine with lights on.  Took it to dealer and they couldn’t make the lights come on so they couldn’t diagnose it. Any ideas?  I tested the speed sensors and of course they were fine and the lights were not on?

[RX400h]

3 hours ago, JohnBros said:

I have been having this issue in my 1998 GS300 for several years. As I drive the lights will come on and speed o meter stops working until I got it off and restart. No other things seem to be happening. Car runs fine with lights on.  Took it to dealer and they couldn’t make the lights come on so they couldn’t diagnose it. Any ideas?  I tested the speed sensors and of course they were fine and the lights were not on?

Quote

Copilot

Sent by Copilot:

It sounds like a frustrating issue, especially since it’s been ongoing for years. Given the symptoms you described, here are a few potential causes and solutions:

1. Instrument Cluster Issues: The problem might be with the instrument cluster itself. This is a known issue in some Lexus models where the cluster can fail intermittently. Replacing or repairing the instrument cluster might resolve the issue.

2. Vehicle Speed Sensor (VSS): Even though you tested the speed sensors and they seemed fine, they can sometimes fail intermittently. The VSS sends speed information to the car’s computer, and if it’s faulty, it could cause the speedometer to stop working.

3. ABS and VSC Systems: Problems with the ABS (Anti-lock Braking System) and VSC (Vehicle Stability Control) can also cause the speedometer to stop working. If the ABS sensor or the ABS ECU (Electronic Control Unit) is faulty, it might trigger the lights and affect the speedometer.

4. Wiring and Connectors: Check the wiring and connectors related to the speed sensors and the instrument cluster. Loose or corroded connections can cause intermittent issues.

5. Fuses: Sometimes, a blown fuse can cause the instrument cluster to malfunction. Check the fuses related to the instrument cluster and speed sensors.

Since the dealer couldn’t replicate the issue, it might be worth visiting a specialist who has experience with older Lexus models. They might be more familiar with these intermittent issues and have better diagnostic tools.

Have you noticed any patterns or specific conditions when the lights come on and the speedometer stops working? This information could help narrow down the cause.

 

[Gunnut]

I'm having the same issue in my 98 GS4. Replaced both rear speed sensors and the 2 transmission speed sensors.

Everything works on the cluster except the speedometer and the odometer. (243k on the clock). Car drives and brakes as normal (haven't attempted emergency stop to test abs). 

Crusie control works fine maintaining speed and engages and disengauges normally.

Traction control not working as to applying brakes to spinning wheel but will beep when traction is lost.

I have a used ABS ecm that installs under the dash I'm going to install. The pump/booster was replaced before I bought the car in 2007 (91k on the clock).