Mitsubishi 3000GT Service Manual page 868

SERVICE BRAKES - Anti-lock Braking System Troubleshooting
E-3 When diagnostic trouble code "21 G SNSR." is displayed
[Explanation]
The ABS-ECU outputs this diagnostic trouble code
in the following cases.
G sensor OFF trouble (It is judged that the
l
G sensor continues to be OFF for more than
approximately 13 seconds except when the
IGNITION
SWITCH (:S2)
NOTE
l
Is G sensor normal?
(Refer to P.35117.)
Yes
Yes
ABS-ECU malfunction
TSB Revision
vehicle is stopped or when there is stop light
switch input.)
When there is a broken wire or short circuit
in the harness for the G sensor system.
Replace G sensor.
Repair harness.
Replace ABS-ECU.