Ldle Speed Control Valve; Checking And Replacing - BMW 5251 Service Manual

130-1 3
Fuel Injection
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Unplug harness connector (arrow) from sensor.
CAUTION-
Be sure ignition is OFF before disconnecting or reconnecting
DME system components.
NOTE-
Do not confuse the throttle position sensor on the main Nirot-
tle body with the throttle position switch on the secondary
throttle body, where applicable.
-
Remove two mounting screws holding sensor to throttle
housing.
-
Installation is reverse of removal. Clear adaptation settings
from ECM using BMW-compatible scan tool.
NOTE-
Poor idle quality may be noticeable for a period i f the adapta-
tion settings are not cleared after installing new TPS.
ldle speed control valve,
checking and replacing
The idle speed control valve regulates idle speed by redirect-
inq airaround the throttlevalve.The idlespeed control valve is
mounted on the underside of the intake manifold adjacent to
the dipstick tube bracket. Accessing the valve is best accom-
plished by first removing the air filter housing and the throttle
body assembly.
The valve issupplied with batteryvoltagefrom the ECM relay.
The idle speed control valve incorporates a two-coil rotary ac-
tuator. The ground sides of each coil are pulsed sirnulta-
neously by the ECM. The duty cycle of each circuit is varied to
achieve the required idle speed.
Afaulty ldle speed control valve sets afault code and the MIL
is illuminated when OED II fault criteria are exceeded.
Before checking the idle speed control valve, confirm that the
throttle position sensor is working correctly.
-
With engine running, check that idle speed control valve is
buzzing.
-
Turn on AIC system or shift transmission into drive. ldle
should remain steady or increase slightly.