Discovery II
EMISSION CONTROL - V8
DESCRIPTION AND OPERATION 17-2-27
The ECM connector and pins pertinent for secondary air injection are listed in the following table:
Secondary Air Injection System Components
The secondary air injection (SAI) system components (where fitted) are described below:
Secondary Air Injection (SAI) Pump
1 SAI pump cover
2 Foam filter
3 SAI pump
4 Pressurised air to exhaust manifolds
The SAI pump is attached to a bracket at the rear RH side of the engine compartment and is fixed to the bracket by
three studs and nuts. The pump is electrically powered from a 12V battery supply via a dedicated relay and supplies
approximately 35kg/hr of air when the vehicle is at idle in Neutral/Park on a start from 20
°
C (68
°
F).
Air is drawn into the pump through vents in its front cover and is then passed through a foam filter to remove
particulates before air injection. The air is delivered to the exhaust manifold on each side of the engine through a
combination of plastic and metal pipes.
Connector / Pin No.
Description
Signal type
Control
C0635-23
Main relay output
Output drive
Switch to ground
C0636-4
Secondary air injection vacuum solenoid
valve control
Output, drive
Switch to ground
C0636-16
Secondary air injection pump relay control
Output drive
Switch to ground
C0636-21
Coolant temperature (ECT) sensor
Ground
0V
C0636-22
Coolant temperature (ECT) sensor
Input signal
Analogue 0 - 5V
C0637-20
MIL "ON"
Output drive
Switch to ground
M17 0204
1
4
2
3
