Mitsubishi 3000GT Service Manual page 866

SERVICE BRAKES - Anti-lock Braking System Troubleshooting
When the following diagnostic trouble codes are displayed "11 FL SNSR. OPEN" "12 FR SNSR.
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OPEN" "13 RL SNSR. OPEN" "14 RR SNSR. OPEN"
[Explanation]
The ABS ECU detects breaks in the wheel speed
sensor wire. This diagnostic trouble code is output
if the wheel speed sensor signal is not input (or
short circuited) or if its output is low when starting
to drive or while driving.
When diagnostic trouble code "15 VEH. SPD. SNSR." is displayed
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[Explanation]
This diagnostic trouble code is output when there
is an abnormality (other than broken wire or short
circuit) in any of the wheel speed sensor output
signals while driving.
[Hint]
The following can be considered as the cause of
the wheel speed sensor output abnormality.
Distortion of rotor, teeth missing
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Low frequency noise interference when sensor
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harness wire is broken
Noise interference in sensor signal
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Sensor output signal is below the standard val-
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ue or amplitude modulation is overthe standard
value. Using an oscilloscope to measure the
wave shape of the wheel speed sensor output
signal is very effective.
Broken sensor harness
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[Hint]
In addition to a broken wire/short circuit in the wheel
speed sensor, also check whether the sensor gap
is too large, sensor harness wire is broken, or sensor
harness and body connector are not properly con-
NOTE
(1) If contact is poor, check the sensor cable by
bending and lightly stretching it.
(2) Except for the case where a fault condition
exists in the system, but the inspection results
are normal; if an abnormality cannot be found
in the sensor circuit displayed as abnormal,
erase the diagnostic trouble code and turn the
ignition switch to OFF once, and then test-drive
again.
If the same diagnostic trouble code is output,
replace the ABS ECU. If the trouble does not
occur anymore, the problem is likely to be with
the ABS ECU.
(If the trouble is in the speed sensor circuit,
but is difficult to recreate, it will recur even after
the ABS ECU has been replaced.)
SPEED SENSOR
FRONT CLH) FRONT (RH; REAR (LH) REAR (RH)
NOTE
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