Mazda 323, 2002, 83,000 miles, recently the ABS, Brake and TCS warning lights have illuminated, when the Hand brake is off and brake fluid level full. Is this a sensor issue, or something more sinister. Also a cluncking noise coming from the front nd during braking, although all brake pads/disks have recently been checked

Still sounds like an ABS problem - get a code reader and carefully check all trouble codes.

tcsd and abs work of sensors on all wheels so check for wiring and connections
brake light ( on dash) can be low fluid level in the brake reservoir, hand brake still on
run the fault codes to find exact codes that are putting the lights on

Only if the warning light showed on the dash...most often these abs sensors get clogged with brake dust or dislodged during wheel swaps if the pads are fine and fluid level correct...first check the brake pads then the disks and clean the sensors with an old toothbrush and reseat, also check the fluid level on the abs system.this should clear warning light.but any error codes stored on ecu need to be cleared using obd.

have the OBD codes read , sounds like low brake fluid or the brake pads need replacing, the OBD codes will tell you where to get started

PRE-DIAGNOSTIC INSPECTIONBefore diagnosing ABS/TCS, perform a comprehensive visual inspection of system as follows.Check ABS/TCS wiring harness connectors for looseness. Check harness routing; pay particular attention to wheel speed sensor wiring harness routing. Check fuses No. 1D, 5B and 6B in instrument panel fuse block. Check fuses No. 1 and 2 in underhood fuse block. Check brake fluid level in master cylinder reservoir. Check brake fluid level in Pressure Modulator Valve (PMV) assembly reservoir. Ensure parking brake is fully released. Ensure parking brake switch is functioning properly. Always perform ABS/TCS system functional check before using DIAGNOSTIC CODE CHARTSThe EBCM/EBTCM has self-diagnostic capability, which can detect system failures. Fault codes stored by EBCM/EBTCM can be displayed using Tech 1 scan tester. There are no provisions for flash code diagnostics.Begin ABS/TCS diagnosis with PRE-DIAGNOSTIC INSPECTION procedure. If failures are found during pre-diagnostic inspection, perform necessary repairs, and proceed with ABS/TCS FUNCTIONAL CHECK. See Fig. 5 .If no failures are found during pre-diagnostic inspection, go to ABS/TCS FUNCTIONAL CHECK. See Fig. 5 . The ABS/TCS FUNCTIONAL CHECK will either indicate ABS/TCS is functioning properly or direct technician to various diagnostic procedures such as diagnostic charts, symptom diagnosis or BRAKE warning light diagnosis.CHART D - TRACTION OFF WARNING LIGHT ON CONTINUOUSLY & NO DTC SET (BUICK WITH UH8 OR U2A INSTRUMENT CLUSTER)Circuit DescriptionWhen ignition switch is first turned to RUN position, EBTCM goes through a self-test, which lasts 2-4 seconds. During self-test, EBTCM commands TRACTION OFF indicator warning light on. Powertrain Control Module (PCM) can also command EBTCM to set a Code 75 which will illuminate TRACTION OFF indicator.Traction control switch is located either on instrument panel center trim plate or driver's front door trim panel. Switch allows driver to select traction control mode (on/off). When traction control system is turned off, TRACTION OFF warning light comes on.EBTCM monitors transaxle temperature through

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.

The brake light will illuminate when the hand brake is on and when the brake fluid is low. Have you checked to make sure the brake fluid is full in the master cylinder reservoir?

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

The traction control gets its information from the ABS system, so a faulty sensor reading will automatically shut down the traction control system.

It is common in this vehicle for the sensor to malfunction!

Brake system warning
Momentarily illuminates when the
ignition is turned to the START
position. Also illuminates if the
parking brake is engaged. If the
brake warning lamp does not
illuminate at these times, seek service immediately. Illumination after
releasing the parking brake indicates low brake fluid level and the brake
system should be inspected immediately.
Anti-lock brake system (ABS)
Momentarily illuminates when the
ignition is turned to the ON
position. If the light remains on,
continues to flash or fails to
illuminate, have the system serviced
immediately. With the ABS light on, the anti-lock brake system is
disabled and normal braking is still effective unless the brake warning
light also remains illuminated with the parking brake released.

Here is a link to your free owners manual with an explanation of all the lights and features of your car as well...

http://safemanuals.com/user-guide-instructions-owner-manual/LINCOLN/TOWN%20CAR%202000-_E

Click on the PDF user guide on the right side.

depending on the system if it is 2 channel or 4 channel one of the sensors that are located on the backing plate located behind calipers is eithier faulty or dirty you can try brake cleaner these sensors use a small magnet pickup device to sense when the wheel "locks up"