ambient temp sensor BMW 528i 1999 E39 Workshop Manual

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Fuel Injection 1
NOTE-
The 1998 5281' with MS 41.1 requires a barometric pressure
sensor input signal for activation of the
LDP check. This sen-
sor is located on the passenger side strut tower
fo~lard of
ABS/ASC hydraulic unit.
Evaporative emissions
1. ECM
2. Purge valve
3. Leak detection pump (LDP) (in
lefl rear wheel housing)
4. Filter
5. Liquid vapor separator
6. Purge canister
7. Fuel tank
Secondary air injection, overview
The secondary air system pumps ambient air into the exhaust
stream afler a cold engine start to reduce the warm up time of
the catalytic converters and to reduces HC and CO emis-
sions. The ECM controls and monitors the secondary air in-
jection system. The secondary air pump operates at a start
temperature of between 10°C (50°F) and 40°C (104°F) and
continues to operate for a maximum of
2 minutes at idle
speed.
The electric air pump draws in ambient air and supplies it to
the divertervalve. The vacuum ventvalve (solenoid) switches
vacuum to open the divertervalve when activated by the
ECM. Once opened, the diverter valve allows air to be
pumped into the exhaust stream.

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130-75
Fuel Injection
Secondary air injection, overview
The secondary air system pumps ambient air into the exhaust
stream afteracoid engine start to reduce the warm-up time of
the catalytic converters and to reduces HC and CO emis-
sions. The ME
7.2 ECM controls and monitors the secondary
air injection system. The secondary air pump operates at a
starttemperature of between 10°C
(50°F) and 40°C (104°F).
and continues to operate for a maximum of
2 minutes at idle
speed.
The electric air pump draws in ambient air and supplies it to
the
checlc valve. The vacuum vent valve (solenoid) switches
vacuum to open the
checlc valve when activated by the ECM.
Once opened, the checlc
valve allows air to be pumped into
the exhaust stream.
4 The secondary air injection system consists of the following
components:
1. Secondary air pump relay
2. Oxygen sensors
3. Catalytic converters
4. Electric air pump
5. Non-return valve
6. Vacuum vent valve