LAND ROVER V8
27
DESCRIPTION AND OPERATION
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P1191 - Oxygen sensor heater circuit open
circuit, downstream sensors
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P1192 - Oxygen sensor heater circuit short
circuit, downstream sensors
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P1193 - Oxygen sensor heater circuit inferred
open circuit, downstream sensors
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P1194 - Oxygen sensor heater circuit high
resistance, downstream sensors
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P1195 - Oxygen sensor heater circuit inferred
low resistance, downstream sensors
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P1196 - Oxygen sensor heater circuit low
resistance, downstream sensors
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P0420 - Catalyst efficiency is low, bank A
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P0430 - Catalyst efficiency is low, bank B
Fuel pressure regulator - (up to 99MY only)
The fuel pressure regulator is a mechanical device
controlled by manifold depression and is mounted at
the rear of the engine in the fuel rail. The regulator
ensures that fuel pressure is maintained at a constant
pressure difference to that in the inlet manifold. As
manifold depression increases, the regulated fuel
pressure is reduced in direct proportion. When
pressure exceeds the regulator setting, excess fuel is
spill returned to the fuel tank swirl pot which contains
the fuel pick up strainer.
Failure of the regulator will result in a rich mixture at
idle but normal at full load, or a rich mixture resulting
in engine flooding, or a weak mixture. Although the
fault will not illuminate the MIL, faults caused by the
failure may be indicated.
Accumulator - (up to 99MY only)
Certain derivatives have an accumulator fitted into the
feed line connection at the fuel rail. The purpose of
this device is to damp out pulsations in the fuel
system caused by the normal opening and closing of
the injectors. These pulsations, called injector knock,
may otherwise be detected inside the vehicle.
Relays - (up to 99MY)
The engine management system employs four relays,
which are all located in the main under bonnet
fusebox.
Main Relay:
The main relay supplies the power feed to the ECM to
feed the fuel injectors (8 amps)and air flow meter (4
amps). This relay is controlled by the GEMS ECM
which has a second power feed. This enables the
ECM to remain powered up after ignition is switched
off. During this ’ECM power down routine’ the ECM
records all temperature readings and powers the
stepper motor to the cold start position. Failure of this
relay will result in the engine management ECM not
being powered up, resulting in engine not starting due
to absence of fuel and ignition.
Starter Motor Relay:
The starter motor relay is ignition key controlled and
activated with the key in position 3 only. Releasing the
key after cranking cuts supply to the relay and
switches off the starter motor. Failure of this relay will
result in the starter motor not working.