NO.5 ABS OPERATES FREQUENTLY [ANTILOCK BRAKE SYSTEM (ABS)]

id040308109400

5

ABS operates frequently

POSSIBLE CAUSE

• Difference in size or air pressure between front and rear tires.

• Incorrect ABS wheel-speed signal is input to ABS HU/CM.

5	ABS operates frequently
POSSIBLE CAUSE	• Difference in size or air pressure between front and rear tires. • Incorrect ABS wheel-speed signal is input to ABS HU/CM.

Diagnostic procedure

STEP	INSPECTION		ACTION
1	CONFIRM ABS HU/CM AND PCM DTC • Retrieve the ABS HU/CM DTC using the M-MDS. (See DTC INSPECTION [ABS HU/CM].) • Retrieve the PCM DTC using the M-MDS, if the traction control function has a problem. (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-G 1.3, SKYACTIV-G 1.5)].) (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-D 1.5)].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [ABS HU/CM].) (See DTC TABLE [PCM (SKYACTIV-G 1.3, SKYACTIV-G 1.5)].) (See ON-BOARD DIAGNOSTIC TEST [PCM (SKYACTIV-D 1.5)]
1		No	Go to the next step.
2	INSPECT TIRE SIZE AND AIR PRESSURE • Inspect tire size and air pressure. • Is the tire size and air pressure as specified?	Yes	Go to the next step.
2		No	Replace with specified tires and adjust tire air pressure.
^*3	INSPECT ABS WHEEL-SPEED SENSOR OUTPUT PULSE • Perform the Voltage Pattern Inspection for each ABS wheel-speed sensor. (See FRONT ABS WHEEL-SPEED SENSOR INSPECTION.) (See REAR ABS WHEEL-SPEED SENSOR INSPECTION.) • Is the output voltage pattern normal?	Yes	Found malfunctioning part according to the “INTERMITTENT CONCERN TROUBLESHOOTING”. (See PRECAUTION [ANTILOCK BRAKE SYSTEM (ABS)].)
^*3		No	ABS wheel-speed sensor installation inspection: • Inspect the ABS wheel-speed sensor for looseness and confirm it is securely installed. ABS sensor rotor installation inspection: • Inspect the ABS sensor rotor for poor installation. Repair or replace any malfunctioning parts according to the inspection result.

• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while doing the inspection to discover whether poor contact points are the cause of any intermittent malfunctions. If there is a problem, verify that connectors, terminals and wiring harnesses are connected correctly and undamaged.