Land Rover Engine Management Systems Rover Manual

13/14CU AND 14CUX SYSTEMS
13/14CU and 14CUX Systems 89 A/C Fan Switch Input (13CU and 14CU only)
This indicates that heater or A/C blower motor operation has been requested via the dash 
control panel.  On 13CU  systems, this is the only Air Conditioning system input signal.  The 
ECM will compensate for the additional engine load and adjust idle speed accordingly.  On 
14CU systems, this signal is used in combination with the A/C thermostat input signal.
A/C Thermostat Input (14CU and 14CUX only)
By...

13/14CU AND 14CUX SYSTEMS
90 OUTPUTS
Main relay
The ECM provides power to both fuel injector banks, MAFS, the fan module, and fault display 
via the main relay.  The relay is located under the passenger seat on most models.  For 1995, 
the relay has been moved to the engine compartment where it is mounted on the passenger 
side fender wall.  On Defender, the relay is mounted on the passenger side of the bulkhead.
Fuel Pump Relay
The fuel pump relay is located next to the main relay.  The ECM provides...

13/14CU AND 14CUX SYSTEMS
13/14CU and 14CUX Systems 91 Fuel Injectors
The ECM provides ground side switching to both A (pin 13) and B (pin 11) injector banks.  
Banks are operated alternately except at start-up when simultaneous operation is used to 
provide additional fuel to the system.  Injectors are shut off during deceleration.
The ECM controls fuel volume through injector pulse width.  Pulse width varies between 
approximately 2.4 milliseconds at idle to a maximum of approximately 9.0 milliseconds...

13/14CU AND 14CUX SYSTEMS
92 Inertia Switch
The inertia switch isolates the power supply to fuel pump in the event of extreme deceleration 
like that which would occur in a collision.  The inertia switch is located under the left front seat 
on 1987-1994 vehicles, and on the bulkhead at the back of the engine compartment from 1995.  
It can be reset by pressing the button at the top of the switch.
Inertia Switch 1987-1994
Inertia Switch 1995 

13/14CU AND 14CUX SYSTEMS
13/14CU and 14CUX Systems 93 Engine On-Board Diagnostic (OBD) System 
Much of the new technology introduced on these engine control systems is directed toward 
improving the quality of exhaust gas emissions and reducing air pollution.   Much of this has 
been mandated by legislation that originated with the California Air Resources Board (CARB).  
Control system self-diagnostics, or On-Board Diagnostics (OBD) for vehicle emissions are 
included in the 14 CUX engine control...

13/14CU AND 14CUX SYSTEMS
94 System Fault Codes
13CU and 14CU systems have a limited number of self-diagnostic fault codes, however all of 
the basic system areas such as Oxygen Sensors, Throttle Potentiometer, Air Flow Sensor, and 
Coolant Sensor are monitored.
14CUX sytems are OBD (I) compliant, and will display the following faults, which are listed in 
order of display priority:
Code Description
02 ECM Power Disconnected (displays only until first key on/key
off cycle)
29 ECM Memory Check
44 Lambda...

13/14CU AND 14CUX SYSTEMS
13/14CU and 14CUX Systems 95 SYSTEM DIAGNOSTICS
A technicians approach to diagnostics of any vehicle system should include the following steps:
•  Verify the customer concern
•  Determine related symptoms
•  Isolate the source of the concern
•  Perform the required repair
•  Verify system operation
As indicated, the first step in vehicle diagnosis is verification of the customers concern.  This 
can eliminate time spent unnecessarily searching for the cause of a normal operating...

13/14CU AND 14CUX SYSTEMS
96 Using this diagnostic connector allows you to perform system diagnostics without removing the 
harness connector from the ECM and clear codes without diagnostic equipment.
Diagnostic Connector Locations 

13/14CU AND 14CUX SYSTEMS
13/14CU and 14CUX Systems 97 TestBook Connections
Selecting the correct accessory cables is critical when using the TestBook for system diagnosis.  
Cables can vary for each application.
Once you have selected the proper cables, ensure that they are securely connected and 
plugged into Socket 1 at the back of the TestBook unit.  Next, connect the clip on the power lead 
to the positive (B+) post of the vehicles battery.  You are now ready to enter TestBook 
diagnostics.
TestBook...

13/14CU AND 14CUX SYSTEMS
98 Touch the system icon to move on to the next selection screen.
TestBook provides you with the opportunity to monitor the function of the system inputs listed on 
the screen below.