1997 MAZDA MX-5 relay

ANTI-LOCK BRAKE SYSTEM
1997 BRAKES Mazda - Anti-Lock
DESCRIPTION
The Anti-Lock Brake System (ABS) control module senses reductions in front and rear wheel speed and
modulates hydraulic pressure to the brakes to prevent wheel lock-up. The ABS consists of a hydraulic unit, 4
wheel speed sensors and sensor rotors, valve relay, motor relay, pump motor and ABS control module. An ABS
warning light is located on the instrument cluster.
OPERATION
Under normal driving conditions, Anti-Lock Brake System (ABS) functions like a standard brake system. When
vehicle speed reaches 3.8 MPH, ABS will diagnose pump motor by briefly operating motor. Pump motor
operation may be heard inside vehicle.
ABS control module controls ABS by detecting speed sensor signals and activating solenoid valve in hydraulic
unit. Control module also controls pump motor and self-diagnostic function. If a problem is detected in ABS,
ABS will function like a conventional brake system. ABS warning light will also come on.
With detection of wheel lock-up, short pedal pulsations, occurring in rapid succession, will be felt in brake
pedal and steering wheel. Vehicle body may also vibrate slightly. These conditions are normal. Pedal pulsation
will continue until there is no longer a need for anti-lock function or until vehicle is stopped.
COMPONENT LOCATIONS
COMPONENT LOCATIONS CAUTION: See ANTI
-LOCK BRAKE SAFETY PRECAUTIONS article in GENERAL
INFORMATION.
NOTE: For more information on brake system, see BRAKE SYSTEM article.
ApplicationLocation
ABS Control ModuleUnder Carpet, Behind Passenger Seat
Data Link ConnectorLeft Side Of Engine Compartment
Front Sensor RotorOn Front Wheel Hub
Hydraulic UnitRight Rear Of Engine Compartment
Motor & Valve RelaysOn Hydraulic Unit
Pump MotorOn Hydraulic Unit
Rear Sensor RotorOn Rear Drive Axle
Wheel Speed SensorOn Knuckle

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
Microsoft
Sunday, July 05, 2009 1:48:48 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.
Microsoft
Sunday, July 05, 2009 1:48:54 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.

(DLC). Set NGS Adapter (49-T088-003) to ABS. Select VEHICLE & ENGINE SELECTION, then select
vehicle model, engine type and model year. Select DIAGNOSTIC DATA LINK. Select ABS-ANTI
LOCK BRAKE MODULE.
2. Select DIAGNOSTIC TEST MODE and note any codes displayed. See DIAGNOSTIC TROUBLE
CODE DESCRIPTION table. Perform appropriate test. See DIAGNOSTIC TROUBLE CODE (DTC)
TESTING . Clear codes after servicing. See CLEARING CODES .
DIAGNOSTIC TROUBLE CODE DESCRIPTION
DTCProbable Cause
05 Stoplight Switch Wiring Harness
11 Right Front Wheel Speed Sensor/Sensor Rotor
12 Left Front Wheel Speed Sensor/Sensor Rotor
13 Right Rear Wheel Speed Sensor/Sensor Rotor
14 Left Rear Wheel Speed Sensor/Sensor Rotor
15 Wheel Speed Sensor/Sensor Rotor
22 (1) Right Front Solenoid Valve (AV)
23 (2) Right Front Solenoid Valve (EV)
24 (1) Left Front Solenoid Valve (AV)
25 (2) Left Front Solenoid Valve (EV)
26 (1) Rear Solenoid Valve (AV)
27 (2) Rear Solenoid Valve (EV)
51 Valve Relay
53 Motor Relay/Pump Motor
61 ABS Control Module
(1)Pressure retention valve.
(2)Pressure reduction valve.

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
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DTC 05: STOPLIGHT SWITCH WIRING HARNESS
1. Check stoplight switch wiring harness for open or short to ground between stoplight switch and ABS
control module. See WIRING DIAGRAMS
. Repair as necessary. If wiring harness is okay, go to next
step.
2. Clear DTCs. See CLEARING CODES under DIAGNOSIS & TESTING. Recheck for DTCs. If DTC 05
is displayed, replace ABS control module. If DTC 05 is not displayed, a temporary poor contact in wiring
may have occurred and ABS is now functioning properly.
DTCS 11, 12, 13 & 14: WHEEL SPEED SENSOR, SENSOR ROTOR, HYDRAULIC UNIT OR
WIRING HARNESS
1. Check ABS control module connector for poor connection. See COMPONENT LOCATIONS
. Repair
as necessary. If connector is okay, go to next step.
2. Check wiring harness for open or short to ground between suspect wheel speed sensor and ABS control
module. See WIRING DIAGRAMS
. Repair as necessary. If wiring harness is okay, go to next step.
3. Check suspect wheel speed sensor. See WHEEL SPEED SENSORS under COMPONENT TESTING
.
Replace as necessary. If wheel speed sensor is okay, go to next step.
4. Inspect wheel speed sensor rotor for damage or missing teeth. If sensor rotor is damaged or has missing
teeth, replace sensor rotor. If sensor rotor is okay, go to next step.
5. Inspect brakeline for damage. If brakeline is damaged, replace brakeline. If brakeline is okay, go to next
step.
6. Check hydraulic unit. See HYDRAULIC UNIT under COMPONENT TESTING
. Replace as
necessary. If hydraulic unit is okay, go to next step.
7. Clear DTCs. See CLEARING CODES
under DIAGNOSIS & TESTING. Recheck for DTCs after
driving vehicle from a stop to faster than 6.2 MPH. If DTC 11, 12, 13 or 14 is displayed, replace ABS
control module. If DTC 11, 12, 13 or 14 is not displayed, a temporary poor contact in wiring may have
occurred and ABS is now functioning properly.
DTC 15: WHEEL SPEED SENSOR, SENSOR ROTOR, HYDRAULIC UNIT OR WIRING HARNESS
If DTC 15 is displayed, perform DTCS 11
, 12, 13 & 14: WHEEL SPEED SENSOR, SENSOR ROTOR,
HYDRAULIC UNIT OR WIRING HARNESS test.
DTCS 22, 23, 24, 25, 26 & 27: SOLENOID VALVE OR WIRING HARNESS
1. Check ABS control module connector for poor connection. See COMPONENT LOCATIONS
. Repair
as necessary. If connection is okay, go to next step.
2. Check suspect solenoid valve with valve relay installed. See SOLENOID VALVES
under
COMPONENT TESTING. Replace as necessary. If solenoid valve with valve relay installed is okay, go
to next step.
3. Check suspect solenoid valve with valve relay removed. See SOLENOID VALVES
under
COMPONENT TESTING. Replace solenoid valve as necessary. If solenoid valve with valve relay
removed is oka
y, go to next step.

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
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Sunday, July 05, 2009 1:48:48 PMPage 8 © 2005 Mitchell Repair Information Company, LLC.

4. Check wiring harness for open or short to ground between hydraulic unit and ABS control module. See
WIRING DIAGRAMS
. Repair as necessary. If wiring harness is okay, go to next step.
5. Clear DTCs. See CLEARING CODES
under DIAGNOSIS & TESTING. Recheck for DTCs. If DTC
22, 23, 24, 25, 26 or 27 is displayed, replace ABS control module. If DTC 22, 23, 24, 25, 26 or 27 is not
displayed, a temporary poor contact in wiring may have occurred and ABS is now functioning properly.
DTC 51: VALVE RELAY OR WIRING HARNESS
1. Check BTN fuse. Replace as necessary. If BTN or ABS fuse is okay, go to next step.
2. Check valve relay. See VALVE RELAY
under COMPONENT TESTING. Replace as necessary. If
valve relay is okay, check wiring harness for open or short to ground between valve relay and ABS
control module. See WIRING DIAGRAMS
. Repair as necessary. If wiring harness is okay, go to next
step.
3. Clear DTCs. See CLEARING CODES
under DIAGNOSIS & TESTING. Recheck for DTCs. If DTC 51
is displayed, replace ABS control module. If DTC 51 is not displayed, a temporary poor contact in wiring
may have occurred and ABS is now functioning properly.
DTC 53: PUMP MOTOR, MOTOR RELAY OR WIRING HARNESS
1. Turn ignition off and check if pump motor continues to operate. If pump motor continues operating after
ignition is off, replace motor relay. If pump motor does not continue to operate after ignition is off, go to
next step.
2. Check ABS fuse. Replace as necessary. If ABS fuse is okay, go to next step.
3. Check motor relay. See MOTOR RELAY
under COMPONENT TESTING. Replace as necessary. If
motor relay is okay, check wiring harness for open or short to ground between motor relay and ABS
control module. See WIRING DIAGRAMS
. Repair as necessary. If wiring harness is okay, go to next
step.
4. Check pump motor. See PUMP MOTOR
under COMPONENT TESTING. Replace as necessary. If
pump motor is okay, check wiring harness for open or short to ground between hydraulic unit and ABS
control module. Repair as necessary. If wiring harness is okay, go to next step.
5. Clear DTCs. See CLEARING CODES
under DIAGNOSIS & TESTING. Recheck for DTCs. If DTC 53
is displayed, replace ABS control module. If DTC 53 is not displayed, a temporary poor contact in wiring
may have occurred and ABS is now functioning properly.
DTC 61: ABS CONTROL MODULE
1. Check ABS control module connector for poor connection. See COMPONENT LOCATIONS
. Repair
as necessary. If connector is okay, go to next step.
2. Clear DTCs. See CLEARING CODES under DIAGNOSIS & TESTING. Recheck for DTCs. If DTC 61
is displayed, replace ABS control module. If DTC 61 is not displayed, a temporary poor contact in wiring
may have occurred and ABS is now functioning properly.
COMPONENT TESTING

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
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Sunday, July 05, 2009 1:48:48 PMPage 9 © 2005 Mitchell Repair Information Company, LLC.

ABS control module output system (solenoid, relay, etc.) and harness.
5. If all wheels do not operate as specified, check ABS control module input system and wiring harness for
intermittent failure. Check for fluid leakage. Repair as necessary. If input system, wiring harness,
intermittent failure or fluid leakage are not present, replace hydraulic unit.
PUMP MOTOR
1. Turn ignition off. Disconnect ABS Control Module (ABS CM) connector. See COMPONENT
LOCATIONS . Connect Adapter Harness (49-F066-002) to ABS CM connector. Using ohmmeter,
measure resistance between terminal "X" of ABS CM connector and ground. See Fig. 3
. Resistance
should not be more than one ohm. If the resistance is not as specified, check wiring harness between ABS
CM and pump motor. Refer to WIRING DIAGRAMS
. If wiring harness is okay, go to next step.
2. Turn ignition off. Disconnect pump motor/hydraulic unit 2-pin connector. Using ohmmeter, measure
resistance between terminal "B" of pump motor/hydraulic unit connector and ground. See Fig. 7
.
Resistance should not be more than one ohm. Apply 12 volts across pump motor/hydraulic unit 2-pin
connector terminals. Pump motor should operate. If resistance is not as specified or pump motor does not
operate, check wiring harness. If wiring harness is okay, replace hydraulic unit.
Fig. 7: Identifying Pump Motor/Hydraulic Unit Connector Terminals

Courtesy of MAZDA MOTORS CORP.
SOLENOID VALVES
With Valve Relay Installed
Turn ignition off. Disconnect hydraulic unit 12-pin connector. See COMPONENT LOCATIONS. Apply 12

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
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Sunday, July 05, 2009 1:48:48 PMPage 13 © 2005 Mitchell Repair Information Company, LLC.

volts to terminal "A" and ground terminal "D" of hydraulic unit 12-pin connector. See Fig. 8 . Using ohmmeter,
measure resistance between terminal "B" and specified terminals of hydraulic unit connector. See
HYDRAULIC UNIT CONNECTOR TERMINAL RESISTANCE
table. If resistance is not as specified,
check solenoid valves with vale relay removed. See WITH VALVE RELAY REMOVED. Also check valve
relay. See VALVE RELAY.
HYDRAULIC UNIT CONNECTOR TERMINAL RESISTANCE
With Valve Relay Removed
Turn ignition off. Remove hydraulic unit. See HYDRAULIC UNIT under REMOVAL & INSTALLATION .
Remove valve relay from hydraulic unit. Using ohmmeter, measure resistance between terminal "X" of
hydraulic unit valve relay connector and specified terminals of hydraulic unit connector. See Fig. 8
and Fig. 9 .
See HYDRAULIC UNIT CONNECTOR TERMINAL RESISTANCE
table. If resistance is not as specified,
check wirin
g harness. If wiring harness is okay, replace hydraulic unit.
TerminalOhms
"H"4.7
"I"4.7
"J"4.7
"M"9
"N"9
"O"9

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
Microsoft
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Fig. 9: Locating Hydraulic Unit Valve Relay Connector Terminals
Courtesy of MAZDA MOTORS CORP.
ABS WARNING LIGHT
Operational Test
1. Start engine and observe ABS warning light. Light should illuminate for a few seconds. If light does not
illuminate as described, turn ignition off. Disconnect ABS control module connector. Using a jumper
wire, connect terminal AD of ABS control module connector to ground. See Fig. 3
. Turn ignition on.
2. If ABS warning light illuminates, check ABS control module. See ABS CONTROL MODULE. If light
does not illuminate, remove instrument cluster. Remove and check ABS warning light bulb. Replace bulb
as necessary. If bulb is okay, check METER fuse and wiring harness. Repair or replace as necessary. If
METER fuse and wiring harness are okay, go to next step.
3. Using ohmmeter, connect positive lead to terminal 2K (Black/Yellow wire) of instrument cluster and
negative lead to terminal 1K (Blue/Yellow wire) of instrument cluster. See Fig. 10
. If continuity is not
present, replace instrument cluster. If continuity is present, repair wiring harness between instrument
cluster and ABS control module.

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
Microsoft
Sunday, July 05, 2009 1:48:49 PMPage 16 © 2005 Mitchell Repair Information Company, LLC.

Fig. 10: Identifying Instrument Cluster Connector Terminals
Courtesy of MAZDA MOTORS CORP.
STOPLIGHT SWITCH
Disconnect stoplight switch connector. Using ohmmeter, check continuity between stoplight switch terminals.
With brake pedal depressed, continuity should exist. With brake pedal released, continuity should not exist. If
continuity is not as specified, replace stoplight switch.
MOTOR RELAY
1. Turn ignition off. Disconnect ABS Control Module (ABS CM) connector. See COMPONENT
LOCATIONS . Connect Adapter Harness (49-F066-002) to ABS CM connector. Turn ignition on. Using
voltmeter, measure voltage between terminals "X" and AB of ABS CM connector. See Fig. 3
. Voltage
should be zero volts. Apply 12 volts to terminal "B" an d ground terminal "G" of ABS CM connector.
Using voltmeter, measure voltage between terminals "X" and AB of ABS CM connector. Voltage should
be 12 volts. If voltage is not as specified, check wiring harness. If wiring harness is okay, go to next step.
2. Remove motor relay from hydraulic unit. See Fig. 14
. Using ohmmeter, check continuity between
terminals "B" and "C" of motor relay. See Fig. 11
. Continuity should exist. Apply 12 volts to terminal
"C" and ground terminal "B". Using ohmmeter, check continuity between terminals "A" and "D" of motor
rela
y. Continuity should exist. If continuity is not as specified, replace motor relay.

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
Microsoft
Sunday, July 05, 2009 1:48:49 PMPage 17 © 2005 Mitchell Repair Information Company, LLC.