I've got a 94 GS300 which has some swapped Aristo tails. Since I have owned the car, the taillight malfunction lamp has been lit. Searching on the Supra forums showed that those guys have the same problem when switching to the updated Supra lights, and they fix it by upping the resistance in the taillight ECU. No problem, I can do that. I got the specified resistors and my soldering iron out.

When I pulled the old resistors out, I checked them to see that they matched the values I expected. Nope. Expecting 2.7k and 6k ohm. Instead I got 11k and 27k ohm. I installed the ones I had just since I was this deep in, but as expected the light is still on. Anyone beaten this before? Next step is just pull the bulb, but I love having stuff work correctly if I can manage it.

 

did you reset the ecu?

 

how u reset the ECU, and where is the resistor?

 

I presume he is talking about the primary ECU, which will reset with a battery disconnect. I don't think the taillight malfunction ECU has a memory, but it was disconnected for me to swap resistors and it still gave me the error. The resistors I am talking about are on the circuit board itself.

I note that having the ECU disconnected does prevent the light from coming on, but I still wish the feature worked.

 

where is the circut board?

 

the ECU is in the trunkwell on the passenger side above the CD changer location. It is a little red box. You can remove it and pop the black cover off to expose the ECU guts. I'll send the link tomorrow (i have it saved on my laptop) to point you to the Supra page I was using as a guide

 

Fixed. Go to local auto parts store and buy six (6) tail-light bulbs, Sylvania 1157LL. Install them. Done.

The GS300 bulbs are 27W/6.8W, the Aristo bulbs are 20W/5W. That is the problem.

 

a nice low tech solution to a high tech problem

thanks for taking the time to find and post the answer. I was going to install my rear garnish and was curious as to how to fix this problem. Well done

 

ok the problme i have is that my car is an aristo,not a GS300.and i took my old aristo tails off to put the newer stayle tails on

 

The problem is still almost 100% related to this issue. You need to remove the lamp sensor ECU and look at the cover. It states the wattage of bulbs that it is expecting to see. You then need to look at your bulbs to see what the ratings are.