Jaguar XJ (X350). Manual — part 1178

Speed Control - VIN Range: G45704-
>G99999

Principles of Operation

There are two types of speed (cruise) control fitted, adaptive cruise control (ACC) and non-adaptive

cruise control.

For additional information on the operation of either system,

Speed Control - VIN Range: G45704->G99999

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:

For information on the messages displayed, refer to the owner handbook.

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

Mechanical

Electrical

Forward looking radar (FLR) sensor

levelling

Obstructions in the way of the FLR

sensor

Fuses/Relays

Damaged, Loose or Corroded Connector(s)

Damage to Wiring Loom/Incorrect Location, Stretched

or Taught

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

before proceeding to the next step.

5 . If the cause is not visually evident use the Jaguar approved diagnostic system or a scan tool to

retrieve the fault codes before proceeding to the DTC index or the symptom chart if no DTCs are set.

Forward looking radar (FLR) sensor levelling

An incorrectly aligned FLR sensor can cause incorrect system operation. Before starting any repair

work on the ACC system, check the levelling of the FLR sensor. This is carried out in a similar way to

the module levelling in previous systems.

Speed Control Module Alignment - VIN Range: H18680->H99999

Symptom Chart

Symptom

Possible source

Action

Speed control inhibited or

disabled

Default mode enabled

Supply voltage to ACC

module

Supply voltage to FLR

sensor

Steering wheel speed

control switch(es)

Steering wheel speed

control switch
circuit

Throttle sensors

Brake cancel switch

Check message center for default

message.

For ACC module circuit tests, GO to

Pinpoint Test G532451p8.

For FLR sensor circuit tests, GO to

Pinpoint Test G532451p8.

For steering wheel speed control

switch tests, GO to Pinpoint Test
G532451p9.

For steering wheel speed control

switch circuit tests, GO to Pinpoint
Test G532451p9.

For 3.0 L engine throttle position

sensor tests,
Electronic Engine Controls - VIN
Range: G45704->G99999

For 3.5 and 4.2 L engine throttle

position sensor tests,
Electronic Engine Controls - VIN
Range: G45704->G99999

For brake cancel switch tests, GO to

Pinpoint Test G532451p10.

Unable to regulate/adjust

vehicle speed

Steering wheel switch

malfunction

For speed control switch circuit tests,

GO to Pinpoint Test G532451p9.

For speed control switch input signal

tests, GO to Pinpoint Test
G532451p9.

Unable to cancel speed

control from steering wheel

Steering wheel switch

malfunction

For speed control switch circuit tests,

GO to Pinpoint Test G532451p9.

For speed control switch input signal

tests, GO to Pinpoint Test
G532451p9.

Unable to cancel speed

control from brake pedal

Brake cancel switch

malfunction

For brake cancel switch tests, GO to

Pinpoint Test G532451p10.

www.

Diagnostic trouble code (DTC) index

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

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

NOTE:

If the control module/component is suspect and the vehicle remains under manufacturer

warranty, refer to the Warranty Policy and Procedures manual (section B1.2), or determine if

any prior approval program is in operation, prior to the installation of a new module.

NOTE:

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

three decimal places and with a current 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 that involve pinpoint tests.

NOTE:

Inspect connectors for signs of water ingress, and pins for damage and/or corrosion.

NOTE:

If DTCs are recorded and, after performing the pinpoint tests, a fault is not present, an

intermittent concern may be the cause. Always check for loose connections and corroded

terminals.

DTC

Description

Possible Source

Action

C1291

ACC Module

Overheated

Forward Looking Radar

(FLR) sensor is too
warm or too cold

FLR sensor failure

Carry out any pinpoint tests associated

with this DTC using the manufacturer

approved diagnostic system. CLEAR the

DTC. TEST the system for correct

operation. If the DTC returns, INSTALL a

new FLR sensor.

C1292

ACC Blockage

Detection

Forward Looking Radar (FLR)

sensor is blocked

Remove any blockages (snow/leaves etc)

from the FLR sensor. CLEAR the DTC.

TEST the system for normal operation. If

the DTC returns, INSTALL a new FLR

sensor.

C1293

ACC Alignment

Offset Angle Out of

Range

Sensor requires

mechanical levelling

Forward Looking Radar

(FLR) sensor is in
service alignment
mode

Carry out any pinpoint tests associated

with this DTC using the manufacturer

approved diagnostic system. Check FLR

sensor levelling. (This is done in a similar

way to control module alignment in

earlier systems). Complete service

alignment. Refer to the Jaguar approved

diagnostic system.

C1294

ACC Active Speed

Out of Range

Speed related fault with

the engine control
module (ECM),
transmission control
module (TCM),
dynamic suspension
control module
(DSCM), or
instrument cluster
modules

ACC module failure

Carry out any pinpoint tests associated

with this DTC using the manufacturer

approved diagnostic system. Carry out a

full vehicle DTC check. Check the ECM,

TCM, DSCM, or instrument cluster

modules for stored codes. If no DTCs are

indicated in the ECM, TCM, DSCM, or

instrument cluster modules, INSTALL a

new ACC module.

C1459

Adaptive Mode

Switch - Circuit

Failure

Forward alert switch

failure

Forward alert switch to

ACC module circuit
short circuit to
power

Forward alert switch to

ACC module circuit
open circuit

Refer to electrical circuit diagrams, notes

and check the forward alert switch circuit

for failure. For forward alert switch

circuit tests, GO to Pinpoint Test

G532451p1.

C1748

Switch input Circuit -

Short to Ground

Forward alert switch

failure

Forward alert switch to

ACC module circuit
short circuit to
GROUND

Carry out any pinpoint tests associated

with this DTC using the manufacturer

approved diagnostic system. Refer to

electrical circuit diagrams, notes and

check the forward alert switch circuit for

short to ground. For forward alert switch

circuit tests, GO to Pinpoint Test

G532451p2.

www.