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Home >> Jaguar >> 2004 >> XJ (X350) V8-4.2L SC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Information Bus >> Testing and Inspection >> Initial Inspection and Diagnostic Overview

Initial Inspection and Diagnostic Overview



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 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.

Electrical
General
- Fuses (see table)
- Wiring harness
- Correct engagement of electrical connectors
- Loose or corroded connections

- Instrument cluster (IC)
- J-Gate module (JGM)
- Air conditioning control module (A/CCM)
- Dynamic stability control control module (DSCCM)
- Engine control module (ECM)
- Transmission control module (TCM)
- Adaptive speed control control module (ASCCM)
- Yaw rate sensor
- Rear climate control panel (RCCP)
- Air suspension control module (ASU)

- Instrument cluster (IC)
- ICE head unit (HU)
- Rear electronic module (REM)

- Front electronic module (FEM)
- Rear memory module (RMM)
- Navigation module (NAV)
- Steering column lock module (SCLM)
- Electronic park brake module (EPB)
- Driver door control module (DDCM)
- Driver seat control module (DSCM)

- Engine control module (ECM)
- Parking aid control module (PACM)
- Intrusion sensor
- Restraints control module (RCM)
- Left-hand high intensity discharge headlamp assembly (HID)
- Right-hand high intensity discharge headlamp assembly (HID)

- Routing of fibre optic harnesses
- Correct engagement of optical connectors
- Correct placement of optical connectors (ring order)
- Correct assembly of optical connectors (backout, etc)
- Damage to fibre (chafing, abrasion, kinking, cuts, etc)
- ICE head unit (HU)
- Compact disc changer (CD)
- Cellular phone module (CPM)
- Voice module (VACM)
- Rear entertainment system
- Navigation system module (NSM)
- Amplifier (AMP)







4. 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, wait one minute, ignition ON cycle after rectification).

5. If the cause is not visually evident and the Jaguar approved diagnostic system is not available, use a scan tool to retrieve the fault codes before proceeding to the diagnostic trouble code (DTC) index chart, or the symptom chart if no DTCs are set.
6. 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:
- Diagnosis by substitution from a donor vehicle is NOT acceptable. Each vehicle is configured to it's own VID block, and substitution of control modules may not only not confirm a fault, but may cause faults in the vehicle being tested and/or the donor vehicle.
- Electronic modules are sensitive to static electrical charges. If exposed to these charges, damage may result.
- 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.
- Where indicated in the tests, use a suitable oscilloscope. The Jaguar approved diagnostic tester has an oscilloscope function in the 'toolbox' menu.
- Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.

7. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
8. If the cause is not visually evident, verify the symptom and refer to the diagnostic trouble code (DTC) index.

Power Supply and Ground table

Module Action
Instrument cluster (IC) [[G239843p23]].
J-Gate module (JGM) [[G239843p31]].
Air conditioning control module (A/CCM) [[G239843p32]].
Dynamic stability control control module (DSCCM) [[G239843p33]].
Engine control module (ECM) [[G239843p19]].
Transmission control module (TCM) [[G239843p34]].
Adaptive speed control control module (ASCCM) [[G239843p35]].
Air suspension control module (ASU) [[G239843p36]].
ICE head unit (HU) [[G239843p12]].
Rear electronic module (REM) [[G239843p14]].
Front electronic module (FEM) [[G239843p13]].
Rear memory module (RMM) [[G239843p15]].
Navigation module (NAV) [[G239843p11]].
Electronic park brake module (EPB) [[G239843p16]].
Driver door control module (DDCM) [[G239843p17]].
Driver seat control module (DSCM) [[G239843p18]].
Parking aid control module (PACM) [[G239843p20]].
Restraints control module (RCM) [[G239843p22]].
Compact disc changer (CD) [[G239843p6]].
Cellular phone module (CPM) [[G239843p8]].
Voice module (VACM) [[G239843p9]].
Rear entertainment system [[G239843p10]].
Amplifier (AMP) [[G239843p7]].

Driver Information Chart

NOTE:
- Use this table to identify DTCs associated with the message center display, then refer to the DTC index for possible sources and actions.
- For definitions of default modes, see the foot of this table.







Default mode Definitions
LIMP-HOME MODE
- Throttle motor off
- Throttle motor relay off
- Throttle motor circuit off
- Fuel intervention
- Cruise control inhibited

LIMP-HOME UNAVAILABLE
- Power limitation
- Vehicle speed limited to 120 kph
- Reverse throttle progression enabled
- Cruise control inhibited

REVERSE THROTTLE PROGRESSION
- Throttle opening limited to maximum 30%

NOTE: The throttle operation uses the same map as for reverse gear.

ENGINE SPEED LIMITED
- Engine runs normally, up to 3000 rpm
- Engine speed restricted to 3000 rpm maximum, by fuel cut-off

HIGH IDLE
- Throttle valve kept in fixed position by motor
- Cruise control inhibited

SAFETY REDUNDANCY
- Power limitation
- Vehicle speed limited to 120 kph
- Reverse throttle progression enabled
- Cruise control inhibited
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