Antilock Brake System

TROUBLE CODE (21, 23, 25 and 27) - Faulty ABS sensor (Open circuit or input voltage excessive)

1. CHECK RESISTANCE TO ABS SENSOR TO ABS CONTROL UNIT SIDE.
1) Turn ignition switch OFF.
2) Disconnect connector from ABS control unit.





3) Measure resistance between ABS control unit connector terminals.





4) Measure resistance between ABS control unit connector and body.
5) Turn ignition switch ON.





6) Measure voltage between ABS control unit connector and body.

2. CHECK INPUT SIGNAL OF ABS SENSOR TO ABS CONTROL UNIT SIDE.
1) Raise all four wheels of ground.
2) Turn ignition switch OFF.
3) Disconnect connector from ABS control unit.
4) Disassemble connector.





a) While pushing portion (1), disconnect connector.
b) Remove screw from portion (2).
c) Move rubber boot (3) back (toward harness).
d) Slide cover (4) in direction shown by arrow and remove.
5) Connect connector to ABS control unit.
6) Connect the oscilloscope to the ABS control unit connector in accordance with trouble code.
7) Turn ignition switch ON.
8) Rotate wheels and measure voltage at specified frequency.





When this inspection is completed, the ABS control unit sometimes stores the trouble code 29.





3. CHECK ABS SENSOR MECHANICAL TROUBLE.
1) Dismount brake as outlined in manual to gain access to ABS sensor and tone wheel for inspection.
2) Check pole piece and tone wheel for accumulation of foreign particles. If necessary, remove foreign particles and clean.
3) Check tone wheel teeth for cracks for deformities. If necessary, replace lone wheel (No. of teeth 44) with a new one.
4) Check tone wheel for looseness.

Tightening torque:
10 - 16 Nm (1 - 1.6 kg-m, 7 - 12 ft-lb)











5) Measure tone wheel-to-pole piece gap over entire perimeter of the wheel.
If measurements check out "Not OK", adjust the gap using spacers (Part No. 26755AA000). If spacers cannot correct the gap, replace worn sensor or worn tone wheel.

6) Check hub runout.

Specifica1ions 0.05 mm (0.0020 in)

4. CHECK RESISTANCE OF ABS SENSOR.
1) Turn ignition switch OFF.
2) Disconnect connector from ABS sensor.





3) Measure resistance between ABS sensor connector terminals.