Subaru Impreza 2002 Service Manual page 758

13.Idle Mixture
A: INSPECTION AND ADJUSTMENT
1. IDLE MIXTURE
Before measuring the idle mixture, make sure that
the ignition timing and the engine idle speed are
within specifications.
1) Set the gear position at "Neutral" for MT, or "N"
or "P" for AT.
2) Warm up the engine sufficiently until cooling fan
starts to operate.
3) Measure the idle mixture using CO meter.
Engine idle speed
700±100 rpm
4) If out of specification, adjust the idle mixture us-
ing CO adjusting screw of mass air flow sensor.
5) After adjusting the CO value, check and adjust
the increment coefficient of CO resistor by using
Select Monitor.
(1) Select "Current data display & Save" on the
select monitor.
(2) If out of specified data, adjust the increment
coefficient of CO resistor while rotating the CO
adjusting screw.
Specified data:
0.28 — 4.22 V
NOTE:
If driving the vehicle on out of specified data, the
"trouble code 49" is indicated in many case.
IDLE MIXTURE
CO
1.0±0.5%
GI0114A
PM-21
PERIODIC MAINTENANCE SERVICES