1999 MITSUBISHI LANCER EVOLUTION VI sensor
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REAR AXLE – Troubleshooting
3. INSPECTION CHART FOR DIAGNOSIS CODE
Diagnosis
code No.Diagnosis itemsRef. page
12Power supply voltage (valve power supply) system (open- or short-circuit)27-6
21FR wheel speed sensor system (open- or short-circuit)27-6
22FL wheel speed sensor system (open- or short-circuit)27-6
23RR wheel speed sensor system (open- or short-circuit)27-6
24RL wheel speed sensor system (open- or short-circuit)27-6
25Wrong-diameter tire27-8
26Faulty wheel speed sensor27-9
31Steer sensor (ST-1, ST-2, ST-N) system (open-circuit)27-10
32Steer sensor (ST-N) system (short-circuit)27-10
33Steer sensor (ST-N) system27-11
34Steer sensor (ST-1, ST-2) system (short-circuit)27-11
41TPS system (open- or short-circuit)27-12
51Longitudinal acceleration sensor system (open- or short-circuit)27-12
52Longitudinal acceleration sensor27-13
56Lateral acceleration sensor system (open- or short-circuit)27-12
61Stop lamp switch system (open-circuit)27-13
65ABS monitor system (open-circuit or defective ABS)27-14
71Proportioning valve system (open- or short-circuit)27-14
72Directional control valve (right) system (open- or short-circuit)27-15
73Directional control valve (left) system (open- or short-circuit)27-16
81AYC relay system (open- or short-circuit)27-17
82Electric pump system27-18
83Electric pump system27-19
Page 202 of 558
REAR AXLE – Troubleshooting
4. INSPECTION PROCEDURES FOR DIAGNOSIS CODES
Code No. 12: Power supply voltage (valve power supply)
systemProbable cause
This code is output when the AYC-ECU power supply voltage drops below, goes
beyond, a specified level.Defective harness or connector
Defective battery
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.
Disconnect the connector and
measure at the harness side.
Ignition switch: ON
Voltage across 31 and body ground
OK:System voltageNGCheck 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. OKReplace AYC-ECU.NG
Repair
Code Nos. 21, 22, 23, 24: Wheel speed sensor systemProbable 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.Defective harness or connector
Defective ABS-ECU
Defective AYC-ECU
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?YESRefer to Group 35B – Troubleshooting
NO
Measure at B-95 AYC-ECU connector.
Disconnect the connector and
measure at the harness side.
Ignition switch: ON
Turn tire at 1/2 to 1 revolution/sec.
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)OKCheck the following connector:
B-95
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95NG
RepairNG
Repair
Page 203 of 558
REAR AXLE – Troubleshooting
OK
Check the wheel bearing.
NG
Check and repair the harness between
wheel speed sensor and AYC-ECU.
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95NG
Repair
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-52, B-17, A-26, A-50, D-04,
D-14, D-19NG
Repair
OK
Measure at B-95 AYC-ECU connector.
Disconnect the connector and
measure at the harness side.
Resistance across 7-20 (front, LH),
6-19 (front, RH), 9-22 (rear, LH),
and 8-21 (rear, RH).
OK:1.4 – 1.8 kΩ.NGCheck the wheel speed sensor. (Refer
to Group 35B.)
Check the installation of wheel speed
sensor.NG
Repair
OK
Check the wheel speed sensor output
voltage. (Refer to P.27-37)NGCheck the wheel speed sensor and
ABS rotor. (Refer to Group 35B.)NG
Replace
NG
Replace
Page 204 of 558
REAR AXLE – Troubleshooting
Code No. 25: Wrong-diameter tireProbable cause
This code is output if the speed of any one of the four wheels exceeds a specified
level with respect to the average of the four wheel speed sensor outputs when the
steering wheel is in the straight-ahead position and the vehicle speed exceeds 20
km/h. At this time, the warning lamp does not light up.Defective harness or connector
Defective AYC-ECU
Defective ABS-ECU
OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95NG
Repair
OK
Check the trouble symptom.
NO
Measure at B-95 AYC-ECU connector.
Disconnect the connector and
measure at the harness side.
Ignition switch: ON
Turn tire at 1/2 to 1 revolution/sec.
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)OKCheck the following connector:
B-95
YES
Is ABS diagnosis code No. 15 output?YESGroup 35* – Refer to Troubleshooting
Are correct tires mounted on all four
wheels?NO
Repair
NG
Repair
NO
Repair
NOCheck and repair the harness between
wheel speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-52, B-17, A-26, A-50, D-04,
D-14, D-19NG
Repair
OK
Check wheel bearing.NG
Replace
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95NG
Repair
OK
Check wheel speed sensor output volt-
age. (Refer to p. 27-37.)NGCheck wheel speed sensor and ABS
rotor. (Refer to Group 35B.)
YES
Check Wheel speed sensor for instal-
lation.NG
Repair
Are correct tires mounted on all four
wheels?
NG
Replace
Page 205 of 558
REAR AXLE – Troubleshooting
Code No. 26: Wheel speed sensor system (faulty output
signal)Probable cause
This code is output if the speed of one of the four wheels exceeds a specified level
when the vehicle speed is 20 km/h or more. At this time, the warning lamp is turned
on.Defective harness or connector
Defective AYC-ECU
Defective ABS-ECU
OK
Replace ABS-ECU.
NG
Check harness between AYC-ECU
and ABS-ECU.NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
NG
Check the following connectors:
B-24, B-95NG
Repair
OK
Check the trouble symptom.
NO
Measure at B-95 AYC-ECU connector.
Disconnect the connector and
measure at the harness side.
Ignition switch: ON
Turn tire at 1/2 to 1 revolution/sec.
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)NGCheck the following connector:
B-95
Is ABS diagnosis code No. 15 output?YESRefer to Group 35B – Troubleshooting
NG
Repair
NG
Check and repair the harness between
wheel speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-52, B-17, A-26, A-50, D-04,
D-14, D-19NG
Repair
OK
Check wheel bearing.NG
Replace
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the following connector:
B-95NG
Repair
OK
Check wheel speed sensor output volt-
age. (Refer to P.27-37.)NGCheck wheel speed sensor and ABS
rotor. (Refer to Group 35B.)
Check wheel speed sensor for installa-
tion.NG
Repair
NG
Replace
Page 206 of 558
REAR AXLE – Troubleshooting
Code No. 31: Steer sensor (ST-1, ST-2, ST-N) systemProbable cause
This code is output when any of the steer sensors ST-1, ST-2, and ST-N is open-circuited
or the steer sensor ground wire is open-circuited.Defective steer sensor
Defective harness or connector
Defective AYC-ECU
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
NG
Check and repair the harness between
speed sensor and AYC-ECU.
OK
Check the trouble symptom.
OK
Check the trouble symptom.
OK
Check the following connectors:
B-95, B-65, B-98NG
Repair
NG: Voltage remains
at 4 V or more.
Measure at B-98 steer sensor connec-
tor.
Disconnect the connector and
measure at the harness side.
Continuity across 3 and body
ground
OK:ConductingNGCheck the following connectors:
B-98, B-50NG
Repair
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.
Connector connected.
Ignition switch: ON
Voltage across 4/5/17 and body ground.
OK:The voltage alternates between about
3 V and about 0.5 V when the steering
wheel is turned.OKCheck the following connector:
B-95NG
Repair
NG: Voltage alternates
between 4 V or
more and 0.5 V.NG: Voltage
remains
at 0 V.
Code No. 32: Steer sensor (ST-N) systemProbable cause
This code is output when the steering wheel is considered to be turned 40 or more
as determined with ST-1 and ST-2 with ST-N ON (LOW voltage).Defective steer sensor
Defective harness or connector
Defective AYC-ECU
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
NG
Replace AYC-ECU.
OK
Check the trouble symptom.
OK
Check the trouble symptom.
NG
Measure at B-95 AYC-ECU connector.
Disconnect the connector and
measure at the harness side.
Ignition switch: ON
Turn steering wheel about 90 in
either direction from the straight-
ahead position.
Voltage across 17 and body
ground.
OK:No continuityNGCheck the following connectors:
B-95, B-65, B-98NG
Repair
Measure at B-95 AYC-ECU connector.
Connector connected.
Ignition switch: ON
Turn steering wheel about 90 in
either direction from the straight-
ahead position.
Voltage across 17 and body
ground.
OK:The voltage increases from
about 0.5 V or less to about
3 V.OKCheck the following connector:
B-95NG
Repair
Page 207 of 558
REAR AXLE – Troubleshooting
Code No. 33: Steer sensor (ST-N) systemProbable cause
This code is output when the steering wheel is turned 400 or more in the same
direction with ST-N OFF (HIGH voltage).Defective steer sensor
Defective harness or connector
Defective AYC-ECU
NG
Replace AYC-ECU.
Check the trouble symptom.
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.
Connector connected.
Ignition switch: ON
Turn steering wheel about 90 in
either direction from the straight-
ahead position.
Voltage across 17 and body
ground.
OK:The voltage increases from
about 0.5 V or less to about
3 V.NGCheck the following connectors:
B-95, B-65, B-98NG
Repair
Code No. 34: Steer sensor (ST-1, ST-2) systemProbable cause
This code is output if a turning condition is detected for a cumulative period of time
of 15 min. or more, during which there is no change in the steer sensor (ST-1, ST-2)
signals with the wheel speed 15 km/h or more.Defective steer sensor
Defective harness or connector
Defective AYC-ECU
NG
Replace AYC-ECU.
Check the trouble symptom.
OK
Replace the steer sensor.
NG
Check the harness between steer sen-
sor and AYC-ECU.NG
Repair
OK
Replace AYC-ECU.
OK
Check the trouble symptom.
Measure at B-95 AYC-ECU connector.
Connector connected.
Ignition switch: ON
Voltage across 4/5 and body
ground
OK:The voltage alternates
between about 0.5 V and
about 3 V as the steering
wheel is turned.NGCheck the following connectors:
B-95, B-65, B-98NG
Repair
Page 208 of 558
REAR AXLE – Troubleshooting
Code No. 41: TPS systemProbable cause
This code is output when the input from the throttle position sensor falls short of
0.2 V.Defective TPS
Defective harness or connector
Defective AYC-ECU
OK
Replace AYC-ECU.
NG
Check and repair the harness between
AYC-ECU and TPS.
OK
Check the trouble symptom.
NO
Measure at B-95 AYC-ECU connector.
Connector connected.
Ignition switch: ON
Voltage across 18 and body ground
Fully open the throttle valve.
OK:4.5 – 5.0 VNGCheck the following connector:
B-95
Is the MPI diagnosis code No. 14 out-
put?YESRefer to GROUP 13A TROUBLE-
SHOOTING.
NG
Repair
Code No. 51: Longitudinal acceleration sensor systemProbable cause
Code No. 56: Lateral acceleration sensor system
This code is output when the output from the acceleration sensor becomes 0.5 V
or less or 4.5 V or more.Defective longitudinal acceleration sensor
Defective lateral acceleration sensor
Defective harness or connector
Defective AYC-ECU
NG
Replace the acceleration sensor.
OK
Check the trouble symptom.
OK
Check and repair the harness between
acceleration sensor and ignition
switch.
OK
Check the trouble symptom.
NG
Check and repair the harness between
acceleration sensor and AYC-ECU.
NGReplace AYC-ECU.
OK
Check the following connectors:
D-20, D-32
OK
Check the trouble symptom.
OK
Check the trouble symptom.
NG: 4.5 V or more
Check the acceleration sensor. (Refer
to P.27-42.)NG
Replace
NG: 0.5 V or less
Check at D-20, D-32 acceleration sen-
sor connector.
Disconnect the connector and
measure at the harness side.
Ignition switch: ON
Voltage across 1 and body ground
OK:System voltageNGCheck the following connectors:
D-20, D-32, B-49, B-75, B-76NG
Check and repair the harness between
acceleration sensor and AYC-ECU.
NG
Measure at D-20, D-32 acceleration
sensor connector.
Connector connected.
Ignition switch: ON
Voltage across 2 and body ground
OK:0.5 – 4.5 VOKCheck the following connectors:
D-20, D-32NG
Repair
Measure at B-95 AYC-ECU connector.
Connector connected.
Ignition switch: ON
Voltage across 1/3 and body
ground
OK:0.5 – 4.5 VOKCheck the following connector:
B-95NG
Repair
NG
Replace