Mitsubishi 1992 3000GT, Service Manual

Page: 847 / 1308

SERVICE BRAKES Anti-lock Braking System Troubleshooting
E-l
When the following diagnostic trouble codes are displayed “11 FL OPEN” “12 SNSR.
OPEN” “13 RL SNSR. OPEN” “14 RR OPEN”
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I
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[Explanation]
[Hint]
The ABS ECU detects breaks in the wheel speed
In addition to a broken wire/short circuit in the wheel
sensor wire. This trouble code is output if the wheel
speed sensor signal is not input (or short circuited)
speed sensor, also check whether the sensor gap
or if its output is low when starting to drive or while
is too large, sensor harness wire is broken, or sensor
driving.
harness and body connector are not properly
E-2 When diagnostic trouble code “15 VEH. SPD. SNSR.” is displayed
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[Explanation]
This trouble code is output when there is an ab-
normality (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.
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Distortion of rotor, teeth missing
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Low frequency noise interference when sensor
harness wire is broken
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Noise interference in sensor signal
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Sensor output signal is below the standard val-
ue or amplitude modulation is over the standard
value. Using an oscilloscope to measure the
wave shape of the wheel speed sensor output
signal is very effective.
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Broken sensor harness
Poor connection of connector
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.)
(3)
Drive at 19 mph or higher for more than
30 seconds.
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