LamSV

Hello There,

I hope someone can give me some answers.

I have a 94 LS400 with 115,000 miles and I live in Houston TX. Prior to this, I had the common problem as reported in ClubLexus, of instrument cluster not lighted up during the cold months. With warmer months coming back to Houston, my instruments light up within 3 minutes of driving my car first time in the morning. This is a known problem - I do not need further answers here.

However, I had another problem last night. I parked my car to pick up my son from soccer practice. On re-start of the engine, my instrument cluster was fully lighted up ie all needles and indicators were visible (like normal). But my speedometer (needle on zero), cruise control (indicator on OK) and odometer (could read current number but it did not increment) all went dead at the same time. My O/D yellow light was also flickering intermittently. I never have seen this before. My car could still be driven nicely but I was not sure what was going on, especially driving without any speed indication.

Thanks for any tips.

spxChrome

Sounds like the circuit board is going out if not completly out now. they are all tied together.

LamSV

Hello spxChrome,

Thanks for quick response

My question - which circuit board are you talking about? Remember that my instrument cluster is still lighted up ie I can see all the needles, gauges and indicators.

Thanks

spxChrome

Can't remember the name of it. Do a search on dash instrument cluster. There are several threads that talk about this issue and one of them mentions the circuit board with the product number.

shelby

Hi There,

I live in the Netherlands and had the same problems ( seems to be a problem with every <95 LS 400 )

This is a very costly matter, but found a guy in California who can rebuild the print plate and fix the problems.

It will cost you approx $ 195 including freightcost inside the USA

Guy is named Jim Walker email jimlwalker@sbcglobal.net
please tell him I've forwarded you ( or anybody else ) to him. i do not get a dime, but are just curious how many people can be helped by posting this answer

goodluck

John van leijenhorst

LamSV

Hello John,

Thanks for your post.

My problem fortunately was not the "expensive" problem with the cluster instrumentation (combination meter). At least not yet. My instrument lights still take about 5 seconds to light up in the morning, first drive. Remember though, this is a very hot summer in Houston Texas!!! During winter, my instrument lights may take about 15 minutes to come on.

I think I have found the cause of my current problem about 2 weeks ago when I had some time to meddle around during the long Memorial Weekend. I had a faulty Vehicle Speed Sensor No.1. This is the VSS that controls the Speedometer, cruise control and odometer. It also supplies a speed feedback to the ECU (Automatic Transmission Control). In other words, the current symptoms may be due to the VSS No.1 failure.

I actually unplugged the wire connector to the faulty VSS No.1. It is located under the car, somewhere between the 2 front wheels, on the final drive element of the transmission. For those of you with big hands and thick fingers, you may have difficulty trying to reach this connector. Anyway, I injected a square wave (about 10Vpp, 200Hz) directly onto the connector pins (yellow wire = +ve, white wire = -ve). I could immediately see my speedometer reacting up or down depending on my square wave input. Moreover, my odometer was counting up due to the perceived speed. I thought this was really neat. I could create a million miles record for my 1994 LS400!!! I could not directly check my cruise control nor O/D light. But I really suspect that they are all symptoms of the same fault.

My Lexus replacement part has been ordered from irontoad @http://www.irontoad.com/l_home.htm. Their service has been good. I will replace it and hopefully I will also post my results here for others' benefit.

LamSV

GA400

LamSV,

Thanks for sharing what you have found so far. This is great info, hopefully it is what you think it is and you could do a diy explanation post. It appears this problem will happen to all of the first generation LS eventually.

GA400

panos

Any update to this? The web site cited does not exist.

LamSV

Hello panos,

I am not sure exactly what is your question? Please rephrase it and I will check if I can help you.

Regards, LamSV

panos

Mine is pearl white too!

I was wondering if you have a part number. Is VSS1 enough for Carson Toyota?

I am not sure if I need the VSS 1. My instrument panel is bright all the time. Its problem is twofold:
(1) The tach takes a few seconds, sometimes a couple of minutes to wake up. Once it wakes up, it works for the rest of trip, regardless of stops at traffic lights, etc.
(2) The speedo is almost always dead on start up. Some times it works after a mile, sometimes it'll be dead for 30+ miles. On occasion, while it works, it'll go dead after I stop at a traffic light. However, the mile counter keeps incrementing correctly at all times.

The car is in Hawaii, so "cold starts" are always 70+ degrees.

Please let me know if you think the VSS1 may still be related to my speedo fault and if so, where I could get it.

Any other ideas of what to look for are welcome.

Thanks.

PS - The car had an odometer change at 39K by the PO. The car now has 44K miles. (It shows 5K.) The repair was made at Lexus and the printout they gave me reads as follows: "Changed cluster ECU. Note: Speedometer needle problem is a separate repair. Cluster ECU will not fix needle problem."

LamSV

Hello panos,

I do not think the VSS1 issue is applicable in your case. If your VSS1 is dead, your speedometer will read zero all the time and your odometer will not increment. Since your odomter is incrementing, regardless of what your speedometer "needle" is indicating, you may have a problem on the display side, not the signal pickup side (ie VSS1).

My only suggestion, since I do not have this problem, is for you to concentrate on the Instrument Cluster electronics, especially the needle gauges.

Are your needles stuck? Or too much friction? Try tapping the Cluster's front plastic cover to see whether this will free the needles. Try checking this site for related threads on the same issue - stuck or unresponsive needles.

Let us know what you find out.

Regards, LamSV