Mitsubishi 1989-1993 GALANT Service Manual page 434

FUEL SYSTEM <DOHC>
oxygen sensor
side connec
SENSOR INSPECTION
(1) Disconnect the heated oxygen sensor connector, and con-
nect the special tool (harness connector) to the heated ox-
ygen sensor side.
(2) Check that there is continuity [approx. 1252 at 20°C (68"F)]
between heated oxygen sensor connector terminal @ (red
clip of special tool) and terminal @ (blue clip).
(3) If there is no continuity, replace the heated oxygen sensor.
(4) Warm up the engine until the engine coolant temperature
exceeds 80°C (176°F).
(5) Use jumper wires to connect heated oxygen sensor termi-
nal @ (red clip of special tool) and terminal @I (blue clip) to
the battery 0 terminal and 0 terminal.
Caution
Be very careful when connecting the jumper wires
because the heated oxygen sensor will be damaged if
a mistake is made in the connecting terminals.
(6) Connect a digital voltmeter between terminal @ (yellow
clip of special tool) and terminal @ (black clip).
(7) While repeatedly racing the engine, measure the output
voltage of the heated oxygen sensor.
When racing
engine
TSB Revision
Heated oxygen Remark
sensor output
voltage
When the air/fuel mixture ratio
becomes rich by repeatedly
racing the engine, the normal
heated oxygen sensor output is
approximately 0.6-I .O V.