ABS brake light is on

[bustedjimmy]

My ABS light started coming on a few months ago.
I would depress brake pedal and hold it at a stop light, and the light would dissappear for several days.
Now it is on constantly and I have no ABS......

any thoughts?

maybe switch or...

[BlazerLT]

Originally Posted by bustedjimmy

My ABS light started coming on a few months ago.
I would depress brake pedal and hold it at a stop light, and the light would dissappear for several days.
Now it is on constantly and I have no ABS......

any thoughts?

maybe switch or...

To be honest, I would take your truck to the dealer.

This could really be anything and you don't want this system not working properly especially with the winter moving in.

[bustedjimmy]

thanks LT.
One more for ya. My engine light came on - I ran the scanner. Gives me a PO446 code. EVAP cannister vent isplugged is what my cheat sheettells me. What do I do about it?

any help would be greatly appreciated.

[BlazerLT]

Originally Posted by bustedjimmy

thanks LT.
One more for ya. My engine light came on - I ran the scanner. Gives me a PO446 code. EVAP cannister vent isplugged is what my cheat sheettells me. What do I do about it?

any help would be greatly appreciated.

It could be plugged or the solenoid is not working properly.

I hope you are not overfilling your tank. Only fill it until it clicks off once, then top to the nearest dollar.

[bustedjimmy]

Originally Posted by BlazerLT

It could be plugged or the solenoid is not working properly.

I hope you are not overfilling your tank. Only fill it until it clicks off once, then top to the nearest dollar.

That would be wife doing that! any input as to "unplugging" the cannister vent?

[ChrisGood]

Checking The EVAP Control System

Purpose:
An evaporative control system is used to reduce emissions of fuel vapors into the atmosphere by evaporation and to reduce unburnt hydrocarbons emitted by the engine.

Construction:
The system consists of an EVAP Purge Solenoid, a Charcoal Canister, a Pressure Vacuum Filler Cap, and a Rollover and Pressure Relief Valve.

Operation:
The evaporative emission system prevents gasoline vapors in the fuel system from escaping into the atmosphere. When the vehicle is not running, fuel in the fuel tank evaporates. The vapors travel through vent hoses or tubes to be stored in the charcoal canister. Once the vehicle is running, these vapors are drawn into the engine and consumed with combustion gases.




Visual Inspection:

Check routing and condition of all vacuum hoses. SEE Vehicle Emission Control Information (VECI) label, (underhood).
Ensure all vacuum hoses and electrical wires are routed a minimum of three inches from the exhaust manifold, to prevent deterioration due to high temperatures.
NOTE: Use only fuel resistant hoses when servicing the evaporative control system.

Purge Shutoff Switch Test:

Check vacuum hoses for proper routing.
Remove fuel vapor hose from canister and plug.
Remove purge hose from intake manifold.
Remove vacuum signal hose from purge switch and install vacuum pump.
Blow on purge hose, passage should be closed. (If passage is open replace Purge Switch/Canister assembly).
Apply vacuum (15 in/Hg) to signal port of purge switch.
Blow on purge hose, passage should be clear. (If passage is closed replace Canister-Purge Switch assembly).
If Purge Switch is operating properly, reinstall vacuum and vapor hoses.
NOTE: The Charcoal Canister and Purge Shutoff Switch are usually a combined unit and are not serviced separately. If the purge switch or cannister is defective the complete assembly must be replaced.

NOTE: A faulty Purge Shutoff Switch can result in increased emissions and/or poor driveability.

Rollover and Pressure Relief Valve Test:

Inspect fuel and vapor hoses for proper routing, cracks, or restrictions.
Inspect fuel tank cap for proper seal and fit.
Remove fuel tank vent hose from EVAP Canister. Apply light air pressure (3-6 psi.) to the Fuel tank filler tube. Air flow should be present at fuel tank vent hose. If air flow is not present, and Fuel Tank is not over-full, replace Pressure/Relief Rollover Valve.
NOTE: In vehicle rollover valve is in the inverted position the plunger is forced against the guide plate and raw fuel is prevented from flowing through the valve orifice into the fuel tank vent tube.

NOTE: Most vehicles are equipped with only one rollover/pressure relief valve. These dual function valves relieve fuel tank pressure and prevent fuel flow through the fuel tank vent lines should the vehicle be rolled over.

As always, check the service manual for the proper procedures and specifications for your particular vehicle.