Question: Service ASR - ABS Lights

[waikool93]

I have a 93 Roadster that I'd driven daily since 93 - surprise! and have loved all 75K miles.

However, since retirement in '05, I've not driven it as much as I'd like....so it sits and waits and stuff happens that I can't expalin. Recently the idiot screen has flipped up "service ASR" and "service ABS" lights - plus the brake light comes on and goes off while driving. The car seems to drive ok and the brakes feel and work ok as well. I've check the service manuals without resolution. I added a bit of brake fluid and the warning lights went out for a while and then came back on.

Hope there's someone out there who may be able to help. Like to try to resolve the issue myself before taking it to some hack - - unfortunately, they seem to know more than the local Chevy dealer.

 

[Schrade]

Get codes with one of these super duper hi-tech data scanners

Sequenced Code Recovery - 1990 through 1993:
With the interior redesign in 1990, Chevrolet added additional computer capability. The CCM (Central Control Module) was added and a method was provided to display codes on the speedometer of the Corvette.
From 1990 through 1993, you shorted ALDL pin "G" to "A" and turned the ignition to "On" without starting the engine.

This action will cause the speedometer and trip odometer to become a troubleshooting aid:

The codes will display on the speedometer. If there are no codes, the speedometer will show three dashes (---) and if the CCM cannot communicate with the other computers, the letters "ERR" will show up on the display.
The module number associated with the codes will be displayed on the odometer and will show which computer's codes is being displayed.
For the 1990 and 1991 Corvette, the modules are Module "1", the CCM computer and module "4", the ECM module.
For 1992 and 1993, an additional module, module "7", the ABS (Anti-Lock Brake System) and ASR (Automatic Slip Regulation System) codes will be displayed.
The codes will show up for three seconds each and once all codes have been displayed, the speedometer will show three dashes. You can either turn the ignition off for five seconds and then back on to repeat the process or turn the ignition off and remove the short to restore normal operation.


Oops - wrong year!

From here...

 

[waikool93]

Thanks Schrade - I'll give it a try.....also read previous posts about adding more brake fluid.....so, I'll try both.

Thanks again, Ron

 

[Schrade]

Thanks Schrade - I'll give it a try.....also read previous posts about adding more brake fluid.....so, I'll try both.

Thanks again, Ron

Don't forget to replace the air freshener toooooo!
















Just kiddin'. Brake fluid top-off ain't gonna' do squat.

DO check the spark plug wires for proper routing. Misrouted wires will emit radiation, just like a nuke, and will trip false codes on ALL solid-state electronics, like the ABS/ASR system, which is real close to the drivers side wires.

Raise the hood in the COMPLETE dark, fully warmed up, and look for a laser light show. No show does NOT mean you still don't have radiation gettin' loose.

And, get the codes as described above...

Post back up on it.

 

[93Rubie]

Your abs and asr lights are probably unrelated to a red brake light. Is the light just red or is it bright red. E brake switches can stick and cause that. I have seen brake fluid level sensors stick and give false activation.

You need to get codes for the abs and asr lights. Often times it is a bad wheel speed sensor, but it can be other things. Early 2000's Buicks seem to have problems with the wheel speed senor harness getting rubbed through, and putting up the abs light, for instance. You need to get codes.

 

[Schrade]

I have seen brake fluid level sensors stick and give false activation.
.

Now THAT I did not know (and lots of other stuff too). Some fluid level sensors have positive and negative leads that are immersed in [the] fluid, and they measure how much current passes through the fluid... No fluid, no current.

I guess some fluid level sensors have a float mechanism, just like the gas gauge???

 

[93Rubie]

Now THAT I did not know (and lots of other stuff too). Some fluid level sensors have positive and negative leads that are immersed in [the] fluid, and they measure how much current passes through the fluid... No fluid, no current.

I guess some fluid level sensors have a float mechanism, just like the gas gauge???

Correct, some do have floats in them. What you see is what you get.

 

[Schrade]

Correct, some do have floats in them. What you see is what you get.

Which ones have floats? :confused

With sideways and forward/rearward G's tossin' the fluids around, how do they stay accurate?

Only floats I ever heard of was gas tank, and carbuerator in early Shelby GT's, with center-pivot float in the carb bowls for G compensation to stop fuel starvation.

 

[Brian Smith]

Had a similar problem six months ago with the ABS light coming on while stopping. Would stay on till I shut the motor off. Restart and all was OK till next hard brake application.

All fuilds were in good shape level wise but kind of tired in terms of age. One Sunday I hooked my MytyVac brake bleeder to the ABS bleed port in the ABS vault behind the driver seat. Apparently had some smal quantity of air that had precipitated over 16 years and it was moving around inside the ABS valve system. Hard braking would initiate ABS activity and thus trigger the event. Since air is compressible the system barfed a alert. I bled out a couple of 1/2 cc. bubbles and about 1/2 a shot glass of brake fuild till no more bubbles appeared (just to be sure since it's so cheap) and haven't had an issue since.

 

[93Rubie]

Which ones have floats? :confused

With sideways and forward/rearward G's tossin' the fluids around, how do they stay accurate?

Only floats I ever heard of was gas tank, and carbuerator in early Shelby GT's, with center-pivot float in the carb bowls for G compensation to stop fuel starvation.

I don't remember off hand, but they are out there. Like I said what you see it what you get. As far as Corvettes are concerned, none that I know of.

 

[waikool93]

Thanks all: apparently you have to fill the brake fluid to the underside of the opening. I had only put in a little brake fluid to just above the seam line - this was apparently not enough. When I filled it and drove the car, all lights and systems functioned as they should. Yes, the brake light that came on was the red E-brake light and it too has not come back on.

Thanks again - and it looks like everyone had a little fun with this one.