1999 LAND ROVER DEFENDER clutch

ENGINE MANAGEMENT SYSTEM
5
DESCRIPTION AND OPERATION DESCRIPTION
General
An engine control module (ECM) controls the five cylinder direct injection diesel engine, and works on the drive by
wire principal. This means there is no throttle cable, the ECM controls the drivers needs via a signal from the
Throttle Position (TP) sensor on the throttle pedal.
The ECM is a full authoritative diesel specific microprocessor that also incorporates features for air conditioning. In
addition, the ECM supplies output control for the Exhaust Gas Recirculation (EGR) and turbocharger boost
pressure. The ECM has a self diagnostic function, which is able to provide backup strategies for most sensor
failures.
The ECM processes information from the following input sources:
Mass Air Flow (MAF) sensor.
Ambient Air Pressure (AAP) sensor.
Manifold Absolute Pressure (MAP) / Inlet Air Temperature (IAT) sensor.
Engine Coolant Temperature (ECT) sensor.
Crankshaft Speed and Position (CKP) sensor.
Throttle Position (TP) sensor.
Fuel Temperature (FT) sensor.
Air conditioning request.
Air conditioning fan request.
Brake pedal switch.
Clutch pedal switch.
The input from the sensors constantly updates the ECM with the current operating condition of the engine. Once
the ECM has compared current information with stored information within its memory, it can make any adjustment
it requires to the operation of the engine via the following:
Air conditioning clutch relay.
Air conditioning cooling fan relay.
Electronic vacuum regulator solenoid.
Fuel pump relay.
Glow plug warning lamp.
Glow plugs.
Fuel injectors.
Main relay.
Turbocharger wastegate modulator.
Temperature gauge.
The ECM interfaces with the following:
Serial communication link.
Instrument pack.
ProCarManuals.com

18ENGINE MANAGEMENT SYSTEM
22
DESCRIPTION AND OPERATION SWITCH - BRAKE PEDAL
The brake pedal switch is located at the rear of the brake pedal box, and activates when the brake pedal is
operated. The ECM uses the signal from the brake pedal to activate the brake lamps and to limit fuelling under
braking.
The brake pedal switch can fail in any of the following ways:
Switch open circuit.
Short circuit to vehicle supply.
Short circuit to earth.
SWITCH - CLUTCH PEDAL
The clutch pedal switch is located on the clutch master cylinder and is activated when the clutch pedal is operated.
The ECM uses the signal from the clutch pedal switch to provide surge damping during gear change. Surge
damping stops engine speed rising dramatically (engine flaring) during gear change. Surge damping assists
driveability as follows:
Smoother gear change.
Greater exhaust gas emission control.
Improved fuel consumption.
Input / Output
When the clutch pedal is in the rest position, the clutch switch is closed. This allows a feed to flow from the switch
(C0667-1) to the ECM (C0658-35) on a black/white wire. When the clutch pedal is pressed the switch contacts
open, cutting the feed to the ECM.
The clutch pedal switch can fail in any one of the following ways:
Switch open circuit.
Short circuit to vehicle supply.
Short circuit to vehicle earth.
In the event of a clutch pedal switch failure surge damping will be inactive.
ProCarManuals.com

33 - CLUTCH
CONTENTS
Page
DESCRIPTION AND OPERATION
CLUTCH COMPONENTS 2....................................................................................
HYDRAULIC OPERATION 4..................................................................................
DESCRIPTION 6.....................................................................................................
OPERATION 12......................................................................................................
ADJUSTMENT
HYDRAULIC SYSTEM - BLEED 1..........................................................................
REPAIR
CLUTCH ASSEMBLY 1..........................................................................................
BEARING - CLUTCH RELEASE 2..........................................................................
CLUTCH - MASTER CYLINDER LH DRIVE 2........................................................
CYLINDER - CLUTCH SLAVE 4.............................................................................
ProCarManuals.com

CLUTCH
1
DESCRIPTION AND OPERATION This page is intentionally left blank
ProCarManuals.com

33CLUTCH
2
DESCRIPTION AND OPERATION CLUTCH COMPONENTS
ProCarManuals.com

CLUTCH
3
DESCRIPTION AND OPERATION 1.Brake/clutch reservoir
2.Connecting hose
3.Bolt - 2 off
4.Master cylinder
5.Clutch pedal
6.Gearbox housing
7.Primary driveshaft
8.Bolt - 2 off
9.Slave cylinder
10.Bleed nipple
11.Pressure plate
12.Drive plate
13.Dual mass flywheel
14.Metal hydraulic pipe
15.Ball spigot
16.Clutch release bearing sleeve
17.Bolt - 2 off
18.Pivot washer
19.Release lever
20.Release bearing
21.Retaining clip
22.Bolt
23.Plastic hydraulic pipe
ProCarManuals.com

33CLUTCH
4
DESCRIPTION AND OPERATION HYDRAULIC OPERATION
ProCarManuals.com

CLUTCH
5
DESCRIPTION AND OPERATION 1.Brake/clutch reservoir
2.Fluid supply pipe
3.Hydraulic feed pipe
4.Damper
5.Master cylinder
6.Piston
7.Clutch pedal
8.Primary driveshaft
9.Engine crankshaft
10.Drive plate
11.Dual mass flywheel
12.Ring gear
13.Leaf spring
14.Cover - pressure plate
15.Diaphragm
16.Release bearing
17.Ball spigot
18.Release bearing sleeve
19.Release lever
20.Slave cylinder
21.Piston
22.Bleed nipple
ProCarManuals.com