Jaguar XJ (X350). Manual — part 891

Electronic Engine Controls – Armoured

CAUTION: It is imperative that the correct calibration is installed into this engine control module (ECM). In the

event of any doubt, advise should be taken from the Jaguar technical help-line.

Maximum Speed Limit

Modifications have been made to the engine control module (ECM) calibration to improve drivability due to
the extra weight of the glass and armour fitted to the vehicle. If a new ECM is installed, the revised software
must be loaded using the approved Jaguar diagnostic tool. The maximum speed of the vehicle has been
limited to 195 kph (121 mile/h) due to the extra weight of the glass, armour and tire load and speed rating of
the vehicle.

Inertia Fuel Shutoff (IFS) Switch

The fuel pump relay earths through the ECM, via the inertia fuel shutoff (IFS) switch. If, the IFS is
activated, it breaks the path to earth of the fuel pump relay, turning off the fuel pump. The IFS override
switch bypasses the IFS and provides an earth for the fuel pump relay, allowing the vehicle to be driven in
an emergency situation.

Published: Mar 12, 2014

Vehicles

Diagnosis and testing

Electronic Engine Controls - VIN Range:
G00442->G45703

Inspection and Verification

1 . Verify the customer concern.

2 . Confirm which, if any, warning lights and/or messages were displayed on the instrument cluster.

NOTE:

If any warning lights and/or messages were displayed when the fault occurred, refer to the

driver information table for diagnostic trouble codes (DTCs) associated with the display, then to

the DTC index table for possible sources and actions. Some warnings will appear to clear when

the ignition is cycled. This is often because the warning has flagged as a result of one of the

vehicle's on-board diagnostic routines having run to detect the fault. If the same routine is not

run when the ignition is switched ON, the warning will not reflag until the routine does run. See

the DTC summaries for drive cycle routines.

3 . Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection Chart

Mechanical

Electrical

Engine oil level

Cooling system coolant level

Fuel level

Fuel contamination/grade/quality

Throttle body

Poly-vee belt

Fuses

Wiring harness

Electrical connector(s)

Sensor(s)

Engine control module (ECM)

Transmission control module

1 . Verify the following systems are working correctly:

Air intake system

Cooling system

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Charging system

Fuel charging system

Ignition system

2 . If an obvious cause for an observed or reported concern is found, correct the cause (if possible)

before proceeding to the next step

3 . Where the Jaguar approved diagnostic system is available, complete the S93 report before

clearing any or all fault codes from the vehicle.

NOTE:

If a DTC cannot be cleared, then there is a permanent fault present that flags again as soon as it

is cleared. (The exception to this is P1260, which will only clear following an ignition OFF/ON

cycle after rectification).

4 . If the cause is not visually evident and the Jaguar approved diagnostic system is not available, use

a fault code reader to retrieve the fault codes before proceeding to the DTC index, or the symptom

chart if no DTCs are set.

5 . Using the Jaguar approved diagnostic system where available, and a scan tool where not, check

the freeze frame data for information on the conditions applicable when the fault was flagged. The

format of this will vary, depending on the tool used, but can provide information useful to the

technician in diagnosing the fault.

CAUTION: When probing connectors to take measurements in the course of the pinpoint

tests, use the adaptor kit, part number 3548-1358-00.

NOTE:

When performing electrical voltage or resistance tests, always use a digital multimeter (DMM)

accurate to 3 decimal places, and with an up-to-date calibration certificate. When testing

resistance, always take the resistance of the DMM leads into account.

NOTE:

Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.

Symptom

Symptom (specific)

Possible source

Action

(general)

Non-Start

Engine does not crank

Security system

/Immobilizer engaged

Engine in shut-down mode

ECM relay

Battery

Park/Neutral switch

Starting system

Harness

Engine seized

Check for DTCS. Contact dealer

technical support for

information on security system.

For starting system,

For ECM relay tests, GO to

Pinpoint Test G258127p32.

For battery information,

Battery For Park/Neutral tests,

External Controls For engine

information,

Engine

Engine cranks, but

does not fire

Engine breather system

disconnected/restricte
d

Ignition system

Fuel system

Harness

CKP sensor

ECM fault

Check engine breather system,

Engine Emission Control - VIN

Range: G00442->G45703 For

ignition system,

Engine Ignition - VIN Range:

G00442->G45703 For fuel

system,

Fuel Charging and Controls -

VIN Range: G00442->G45703

For CKP tests, GO to Pinpoint

Test G258127p17.

Contact dealer technical

support for advice on possible

ECM failure.

Engine cranks and fires,

but will not start

Purge valve

Fuel pump

Coolant temperature

sensor

Spark plugs

Check for water ingress

into spark plug wells

HT short to ground

(tracking) check
rubber boots for

For evaporative emissions

components,

Evaporative Emissions - VIN

Range: G00442->G45703 For

fuel system,

Fuel Charging and Controls -

VIN Range: G45704->G99999

For ECT sensor tests, GO to

Pinpoint Test G258127p3.

For ignition system,

Engine Ignition - VIN Range:

G00442->G45703

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