The ABS warning light is located in the instrument cluster. The lamp warns the operator of a possible fault in the system.
When the system is operating correctly, the ABS warning lamp will flash when the ignition switch is initially turned ON , then the lamp will turn OFF . During the lamp illumination the control unit checks the valve relays for proper function. When the ignition is turned to START , power to the ABS controller is interrupted and the warning lamp stays ON . Once the ignition returns to the ON position, power is restored and the system re-checks itself. The warning lamp goes out and should stay off during operation of the vehicle.
READING & CLEARING CODES
See Figures 1, 2 and 3
- Turn the ignition switch ON and OFF several times and observe the ABS warning lamp.
If the ABS warning lamp illuminates constantly, set the system to the diagnosis indication mode as follows:
- Remove the drivers seat.
- Unplug the check connector from the under seat control unit.
- Connect terminal wires G/B and B at the check connector with a jumper wire.
- Start the engine. The system is now in the diagnosis mode.
- Observe the ABS warning lamp. Count the flashes of the lamp.
- Refer to the corresponding chart and correct the indicated item.
After repairs are made or components replaced, cancel the trouble code by following the steps below:
- Connect the G/R and G/B terminals of the check connector with a jumper wire.
- Turn the ignition switch to the ON position.
- Watch for the warning lamp to illuminate and wait 1-2 seconds.
- Turn the ignition switch OFF and disconnect the jumper wire.
- Start the engine and make sure the warning lamp goes OFF.
Only 1 trouble code will be erased, if multiple trouble codes exist, the above procedure must be repeated.1992-98 Vehicles
See Figure 4
To access the codes on 1992-98 models, the following are required: Mazda System Selector Switch 49-BO19-9A0 and Self-Diagnosis Checker 49-HO18-9A1 or a scan tool. If a scan tool is used, be sure it is capable of pulling codes from ABS systems. Not all scan tools have this ability.
- Connect the Mazda system selector switch and the self-diagnosis checker or a scan tool to the underhood data link connector and to a ground. Set the select switch on the checker to A and the system selector knob to position 3. On scan tools, access the ABS menu. Follow the menu on the scan tool to access the codes. If any codes are present it will display the code number and the corresponding circuit or component.
- Turn the ignition switch ON and observe the checker display. Initially, code 88 should appear. If code 88 does not appear check the connections between the checker and the selector. After code 88 appears, watch for and record any other trouble codes.
After the proper repairs are made, the codes must be erased by doing the following:
- At the data link connector under the hood, connect the TBS terminal to GND.
- Turn the ignition switch to the ON position.
- Output all of the memorized trouble codes.
After the first trouble code repeats itself, depress the brake pedal 10 times at intervals of less than 1 second. This will clear all trouble codes.
Remember to first determine if the problem is related to the anti-lock system or not. The anti-lock system is made up of 2 basic sub-systems:
- The hydraulic system, which may be diagnosed and serviced using normal brake system procedures, however, there is a need to determine whether the problem is related to the ABS components or not.
- The electrical system which may be diagnosed using the charts and diagnostic tools.
Before diagnosing an apparent ABS problem, make absolutely certain that the normal braking system is in correct working order. Many common brake problems (dragging lining, seepage, etc.) will affect the ABS system. A visual check of specific system components may reveal problems creating an apparent ABS malfunction. Performing this inspection may reveal a simple failure, thus eliminating extended diagnostic time.
- Inspect the brake fluid level in the reservoir.
- Inspect brake lines, hoses, master cylinder assembly, and brake calipers for leakage.
- Visually check brake lines and hoses for excessive wear, heat damage, punctures, contact with other parts, missing clips or holders, blockage or crimping.
- Check the calipers for rust or corrosion. Check for proper sliding action if applicable.
- Check the caliper pistons for freedom of motion during application and release.
- Inspect the wheel speed sensors for proper mounting and connections.
- Inspect the toothed wheels for broken teeth or poor mounting.
- Inspect the wheels and tires on the vehicle. They must be of the same size and type to generate accurate speed signals. Check also for approximately equal tire pressures.
- Confirm the fault occurrence with the operator. Certain driver induced faults may cause dash warning lamps to light. Excessive wheel spin on low-traction surfaces or high speed acceleration may also set fault codes and trigger a warning lamp. These induced faults are not system failures but examples of vehicle performance outside the parameters of the controller.
- The most common cause of intermittent faults is not a failed sensor but a loose, corroded or dirty connector. Incorrect installation of the wheel speed sensor will cause a loss of wheel speed signal. Check harness and component connectors carefully.
If the battery on the vehicle has been completely drained, always recharge the battery before driving. If the vehicle is driven immediately after jump starting, the ABS self-check may draw enough current to make the engine run improperly. An alternate solution is to disconnect the ABS connector at the hydraulic unit. This will disable the ABS and illuminate the dash warning lamp. Reconnect the ABS when the battery is sufficiently charged.