Abs and emergency brake light illuminate intermittently, but no apparrent problem surfaces.

have vehicle scanned for trouble code possible abs sensor or hub going bad --when abs goes out you still have standard / conventional brakes [ means if you slam on brakes they will lock /skid ] but your brakes will work normal

When I had that problem with the emergency light it was the sensor for emergency brake
The abs and brakes sounds like you are loosing pressure in the system

They only come on sometimes ?
Brake Warning Indicator
The instrument panel cluster (IPC) illuminates the brake warning indicator when the following occurs:
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The body control module (BCM) detects that the park brake is engaged. The IPC receives a class 2 message from the BCM requesting illumination.

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The EBCM detects a low brake fluid condition and sends a class 2 message to the IPC.

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The IPC performs the bulb check.

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An ABS-disabling malfunction also disables dynamic rear proportioning (DRP).

ABS Indicator
The IPC illuminates the ABS indicator when the following occurs:
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The electronic brake control module (EBCM) detects an ABS-disabling malfunction. The IPC receives a class 2 message from the EBCM requesting illumination.

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The IPC performs the bulb check.

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The IPC detects a loss of class 2 communications with the EBCM.

sounds like you have an intermittent problem for now ! a wiring issue or wheel speed sensor going bad. Need to check for codes in abs module , that will give you an Idea where to look first. These systems can set a lot of codes, component codes , wiring codes etc... need to know what code first.

You might check the rear Emergency brakes. The brake linings peel off the mounts and whirl around inside the E brake drum. The ABS sensors react to the garbage grinding up, blinding the sensors.

The fuse for the ABS in a 2002 Highlander is in the black plastic covered box under the hood. If you take the fuse out, the ABS warning light and the emergency brake warning light will illuminate on your dashboard. The brakes will work as if you never had ABS, and the car will chime when you first start off if the emergency brakes are on.

check the brake fluid level in the reservoir. if full, try poking the float back to the surface. sometimes it sticks sunk. the abs light will always illuminate when the red brake light is on if your vehicle is equip t with abs. it means the abs system is inactive.

It stands for Anti-lock braking system, and the reason the ABS warning light is on is due to a problem with the ABS system

BMW MODELS AFFECTED: All with ABS

FAULT: ABS warning light comes on intermittently. Normal troubleshooting procedures find no defect.

Possible Cause: If car has recently had two new tires, or snow tires put on. Sometimes when the car is driven over 50 MPH.

Solution: Check all four tires on the car, make sure they are the same brand, style, and size. Check if
any of the new tires have substantially more tread than the rest. These differences may cause enough
variance in rolling diameters to confuse the ABS control unit, which in turn, gives a false signal to the ABS
warning light.

If that is not the issue, it is most likely the ABS control module failing.

Do you have a brake fluid accumulator(ABS)? If yes, the pistons/pulsing assembly are worn, and may need to be replaced.

If not, you may have a vacuum leak in the power booster (located on the firewall). Check all hose and clamps for a tight fit/cracks,etc. Vacuum leaks cause intermittent brake failure lights.

You may want to park the vehicle on a clean surface, pump the brakes a few times, and check for brake fluid leaks. If there is a leaking wheel cylinder (back brakes) , caliper (front brakes), or brake line, you will be able to see it.

Leaks cause pressure loss, and, thus, the brake warning light will illuminate.

check brake fluid level. Some vehicles have very sensitive sensors in brake fluid reservoir.