myls400

I had my circuit board of my speedometer cluster repaired. After taking out the speedometer cluster, the car is barely driving over 30 miles per hour. I was later told that you are suppose to disconnect the battery before taking out the cluster. Now , my car is not running right at all. Please someone, any one, HELP!

Thanks
93 Lexus LS 400

pscmj

This does sound strange and I’m sure alarming to you, but if the cluster is still out for repair, it is feasible that there is some feedback to the ECU that is missing. Assuming that’s the case, I wouldn’t worry too much as proper operation will most likely return after you reinstall your cluster. If you’ve already reinstalled the repaired cluster, and it appears to be working properly, then probably all you need is an ECU reset. The ECU can be reset by pulling the fuse labeled EFI for a few minutes (probably about five minutes), and then reinstalling. If that doesn’t work, disconnect the negative battery cable for about 5 minutes, and then reconnect. That should do it.

If an ECU reset doesn’t resolve the issue, simply call or drop by your local Lexus dealer and explain the situation. While it may seem a bit awkward, they will be glad to at least let you talk to one of their service technicians for guidance (I’ve found that information is one of the few things they don’t charge for). They were always more than willing to do this for me on other issues. Good luck …

myls400

Thanks for your reply. I did replace the cluster, however, nothing has changed yet. I will try to take the fuse out labled efi. But where is it located?

Mike

pscmj

With the hood open, you should be able to see the plastic fuse box cover on the right just beyond (more toward the firewall) the battery. There is a large slotted plastic screw that holds the cover in place. Once this cover is removed, the fuses are exposed. On the underside of the fuse box cover is a fuse designator.

myls400

I took it to the dealer and you were right, however, they stated that from so much time elapsing, the ignition coil went up on me. I replaced the ignition coil, then followed your direction, now everything is working fine now. THANKS!

By the way, I was also told that had i disconnected the battery first, all of this would've never happened.

pscmj

Certainly gald to hear you're back up and running ... great news!!! Sorry to hear about your ignition coil though. It has always been my experience (and I have worked with electronics since the early '80s), that it is best to disconnect power to electronic equipment BEFORE performing any work. We'll know next time ...