REAR AXLE – Troubleshooting <AYC>
27-7
4. INSPECTION PROCEDURES FOR DIAGNOSIS CODES
Code No. 12: Power supply voltage (valve power supply)
system
Probable cause
This code is output when the AYC-ECU power supply voltage drops below, goes
beyond, a specified level.
D Defective harness or connector
D Defective battery
D Defective AYC-ECU
NOTE
Refer to the corresponding item if any other diagnosis code is being output.
Is the battery voltage correct?
NG
Replace
OK
Measure at B-96 AYC-ECU connector.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Voltage across 31 and body ground
OK: Battery voltage
NG
Check the following connectors:
B-96, B-94, B-49, B-75, B-76
OK
Check the trouble symptom.
NG
Check and repair harness between
ignition switch (IG
2
) and AYC-ECU.
OK
Replace AYC-ECU.
NG
Repair
Code No. 21, 22, 23, 24: Wheel speed sensor system Probable cause
This code is output if any one of three wheel speed sensors fails to provide an input
even after the other wheel exceeded 8 km/h.
D Defective harness or connector
D Defective ABS-ECU
D Defective AYC-ECU
<Vehicles with ABS>
OK
Replace AYC-ECU.
OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.
NG
Repair
OK
Check the trouble symptom.
Is an ABS diagnosis code No. 21, 22,
23, or 24 output?
YES
Troubleshooting
NO
Measure at B-95 AYC-ECU connector.
D Disconnect the connector and
measure at the harness side.
D Ignition switch: ON
D Turn tire at 1/2 to 1 revolution/sec.
D Voltage across 6/7/8/9 and body
ground
OK: 42 mV or more (when mea-
sured with a circuit tester)
120 mV-P or more (when
measured with an oscillo-
scope)
OK
Check the following connector:
B-95
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95
NG
Repair
NG
Repair
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