
REAR AXLE –
Troubleshooting <AYC>
27-6
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: System 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 Nos. 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>
NG
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
Refer to Group 35B – 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