My 97 4Runner has recently started experiencing problems associated with the Dashboard Brake Warning Light. Usually in the morning or after work, when I start the vehicle, the Brake Light will not go off. The engines seen to really struggle and make uncommon noises. The engine runs very rough. At first I thought that the emergency brake was not releasing. But that was not the case. This was infrequent. Now it is happening quite often. Also now the problems has progressively gotten worse. When I try to start the vehicle, it will not start. But several attempts at turning the key off and on, it starts OK. The battery is relatively new and this is not the problems either. I took it to the Toyota dealership and they could not find anything wrong. No errors in the computer log.

I can not make the connection between the Brake Light coming on the rough engine idle. I know that the light usually has to do with the ABS system, or parking brake, but why would this cause a rough engine idle. the engine always has an uncommon sound when this occurs. Usually turning off the engine and restarting cures the problem.

I have read most of the post on the web about the brake light, but none seem to describe the problems I am experiencing.

the vehicle is an SR5, 4WD, 5 speed manual shift. 5VZ-FE engine.

any suggestions would be appreciated.

I can't figure out any connection either.
The normal things that cause the BRAKE lamp to light are the parking brake isn't fully released or the MC is low on brake fluid.

It will also light along with the CHARGE lamp when the alt has a problem.

The brake warning light will also come on if you have an air leak in the brake servo, also any leak would cause the engine to run rough.

You might have a lead here. I have heard a small swishing noise when depressing the brake pedal. I let the toyota service tech listen to it, but the could not find any problems. Still has to be something subtle because I definitely am not imagining this. Have not had the problem in the last several weeks however. Seems to have gone away. Will let you know if I find out what it was.

Did you ever get to the bottom of this problem? Was it the booster?

Any updates on this one? I think I have the same problem as the thread starter's. Hope someone could help us out.

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toyota parts.com

Hello, I know it maybe a bit late with any help but I just read this post so here's my thought. I have a 95 dodge intrepid w/189k on it and within the past 2 months it's been doing the same with the lights and running rough AND the key wasn't quite coming back in the exact spot that it's suppose to. At first not all the time, then all the time. I asked at the local parts place and he said that it might be the key lock cylinder, so I replaced and of course nothing, but in doing so I found out that by just moving the ignition switch [ on the intrepid it's located on the opposite side of the column] slightly that all the dash lights would come on and the car would start and run fine as long as the key came bake to the correct place -- NOTE -- giggle the keys and make sure that they are coming back to the correct spot, that was my problem with the brake light staying on and running rough. --Note -- my other problem is that my ignition switch is bad, I've diconnected this and removed and cleaned up and added dielectric to the connections without any luck, so next thing is to replace the switch. Hope this helps anybody.