Land Rover Bosch 5 2 1 Engine Management Systems Rover Manual

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Bosch 5.2.1 Engine Management System 147 The ECM will also store details of the engine speed, engine load and air temperature in its 
memory. This information is stored to aid diagnosis of the fault
Coolant Sensor Operational Values  
Knock sensors
There are two knock sensors on the V-8 engine, both located 
directly on the cylinder block, one on each side. The knock 
sensors produce a voltage signal in proportion to the amount of 
mechanical vibration generated at...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
148 The ECM uses the signals supplied by the knock sensors in conjunction with the camshaft 
sensor signal, to determine the optimum ignition point for each cylinder. The ignition point is set 
according to pre-programmed ignition maps stored within the ECM. In this case, the ECM is 
programmed to use ignition maps for 95 RON premium specification fuel. It will also function on 
91 RON regular specification fuel but without adaptations. If the only fuel available is...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Bosch 5.2.1 Engine Management System 149 The MAF sensor is sensitive to sudden shocks and changes in its orientation. It should, 
therefore, be handled carefully. It is also important that the intake ducting between the air filter 
housing and the engine plenum chamber is not altered in diameter or modified in any way. The 
air mass flow meter contains electronic circuitry, so never attempt to supply it directly from the 
battery. The terminals have a silver coating...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
150 The ECM will store details of the engine speed, engine load and battery voltage when this fault 
is first detected.
Oxygen sensors
There are four Oxygen sensors used on the V-8 Discovery Series II.  Two of the sensors are 
located in each downpipe. 
11- “Downstream” Sensor tip     12- “Upstream” Sensor tip
One sensor is used upstream of the catalyst, i.e. between the catalyst and the engine, and one 
is used immediately downstream of the catalyst. The two sensors...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Bosch 5.2.1 Engine Management System 151 The Oxygen sensors are very sensitive devices. They must be handled carefully at all times. 
Failure to handle correctly will result in a very short service life, or non-operation.
Oxygen sensors are pre-coated with an anti-seize compound prior to installation. Care should 
be taken to avoid getting this compound on the sensor tip. 
If the sensor needs to be removed and reinstalled, a small amount of anti-seize compound 
should...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
152 The ECM also monitors the efficiency of the catalysts. The ECM uses the signal received from 
the two post-catalyst Oxygen sensors to do this. The state of each catalyst is assessed in line 
with its ability to ‘hold’ Oxygen. In a serviceable unit the ‘excess’ Oxygen in the exhaust gas is 
held on the surface of the precious metal coating of the ceramic blocks within the catalyst. This 
Oxygen is used to convert the harmful elements produced by incomplete...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Bosch 5.2.1 Engine Management System 153 Fuel level signal
This signal is supplied to the ECM by the instrument pack. It is used to alter the fault code 
strategy adopted by the ECM when a misfire is detected (see misfire detection) or if the ECM 
detects that the Oxygen signal is unexpectedly recording a weak air/fuel ratio. It will not stop a 
fault being logged but will modify the fault code to indicate the likely cause of the misfire.
Vehicle speed sensor signal...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
154 The automatic transmission TCM is able to request the illumination of the MIL lamp if it detects 
a fault within its systems that might lead to the vehicle emitting excessive levels of pollutants. It 
is good practice to check both ECM and the automatic gearbox TCM for faults when the MIL 
lamp is illuminated, or a MIL event is logged in the ECM.
Fuel tank pressure sensor
The fuel tank pressure sender is located in the fuel tank. This unit supplies a signal to the...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
Bosch 5.2.1 Engine Management System 155 System Outputs
The ECM receives and processes the input information previously described and modifies the 
fuelling and the ignition points for each cylinder accordingly. The ECM will also supply output 
information to other vehicle system ECUs.
The ECM drives the following components:
•  Fuel injectors
•  Ignition coils
•  Idle speed actuator
•  Main relay and fuel pump relay
•  Purge valve
The ECM provides other systems with...

BOSCH 5.2.1 ENGINE MANAGEMENT SYSTEM
156 Fuel injectors
There are eight injectors (one per cylinder) used on the V-8 
gasoline engine. The ECM controls the injectors directly, 
and individually. It opens an injector by providing a path to 
ground for a voltage supplied by a common fuse. The 
injectors are fed fuel under pressure from a common fuel 
rail. A fuel pressure relief valve, incorporated into the lift 
pump assembly located inside the fuel tank, controls the 
pressure in the fuel rail. In this...