1994 JAGUAR XJ6 steering

rl Electrical
FAULTCODE 13
Air Bag Shorted to Ground
Normal Operation
The DM monitors voltage level at pins 11 and 12 which varies in accordance with charging voltage. If voltage measured
at these two pins falls below 2V the MIL Lamp will illuminate and fault code 13 will be present, indicating a possible
short to ground.
During the presence of fault code 13 the DM internal thermal fuse will blow, disabling the air bag deployment circuit.
If voltage to pins 11 and 12 is restored after the fuse has blown, fault code 51, open internal fuse,
will also be present.
Fault code 13 will be present only as long as the short to ground remains.
Possible Causes
Short to ground in any of the following circuits:
0 Air bag supply wiring.
0 Air bag internal.
0 Cable reel cassette internal.
0 Safing sensor supply wiring.
0 Safing sensor internal.
Fault Diagnosis
1. Air bag(s) -short circuit
. Disarm the SRS system.
. Disconnect both air bag modules multi-plug connector.
. Switch ignition ON.
. Is fault code 13 still present ?
Yes - Proceed to step 2.
No - Proceed to step 3.
2. Cable reel cassette
-short circuit
Examine wiring and connector where cable reel cassette mates to the main harness, below the steering column.
If a fault cannot be located, disconnect cable reel cassette from main harness.
. Connect air bag simulator to the main vehicle harness in place of the cable reel cassettes.
. Measure resistance between pin 11 DM and pin 3 (ground).
. Is pin 11 short circuit to ground ?
No - Proceed to fault code 51.
Yes
- Examine wiring and connections between DM, both air bags and safing sensor. Rectify faults as necessary.
If a fault is located, rectify and proceed to step 3.
3. Air bag modules
-check
. Ensure shorting bar is correctly installed to passenger-side air bag connector.
. Measure resistance between connector terminals and module casing.
If resistance value shows a short to ground, renew the module.
. If resistance shows open circuit, repeat test for driver-side module, renew as necessary.
Proceed to fault code 51 on successful diagnosis.
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rl Electrical
FAULT CODE 32
Driver-side Air Bag Circuit High Resistance or Open
Normal Operation
The DM monitors the resistance between pins 10 and 11. The value of this resistance is the sum of the two cable reel
cassettes, the air bag and is normally between
1.5~2 and 2Q. If the resistance measured exceeds 4Q the MIL Lamp will illuminate and fault code 32 will be present, indicating high resistance or open circuit on the air bag circuit.
Possible Causes
0 Poor connections or corrosion at clockspring / main harness connections.
0 Open circuit or high resistance of cable reel cassettes.
0 Open circuit or high resistance in driver-side air bag.
0 Faulty driver-side air bag wiring.
Fault Diagnosis
1. Circuit - check
. Disarm SRS system and disconnect DM.
Disconnect DM and remove plastic locking wedge from black DM harness connector.
. Measure resistance across harness connections to passenger air bag, wires KN and RF!
. Is resistance value less than 2Q ?
Yes -
. Ensure locking wedge has been removed correctly from black connector.
. Examine harness for broken, dirty or incorrectly seated connections.
. Rectify faults as necessary.
No - Proceed to step 2.
2. Resistance -check
. Is resistance measured in step 1 greater than 352 7
Yes - Proceed to step 4.
No - Proceed to step 3.
3. Fault code verification
. Reconnect DM and check if code 32 is still present.
Yes
- Renew DM.
No - Examine harness or broken, dirty or incorrectly seated connections. Rectify faults as necessary.
4. Resistance -check
. Disconnect cable reel cassette at base of steering column.
Install air bag simulator (ensure 2Q resistance of simulator before connection) in place of cable reel cassette.
Measure resistance across harness connections to air bag, wires KIN and RI?
Is resistance equal to between 1.m and 2.2Q 7
Yes - Renew cable reel cassette.
No - Examine harness wiring for open circuit, rectify faults as necessary.
5. On completion.
. Arm and verify the SRS system.
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FAULT CODE 34
Driver-side Air Bag Circuit Low Resistance or Shorted
Normal Operation
The DM monitors the resistance between pins 10 and 11. The value of this resistance is the sum of the two cable reel
cassettes and the air bag and is normally between 1.552 and 2Q. If the resistance measured is less than 0.752 the MIL Lamp will illuminate and fault code 34 will be present, indicating low resistance or short circuit on the air bag circuit.
Possible Causes
0 Poor connection of cable reel cassettes.
0 Worn cable reel cassette connectors.
0 Short circuit in cable reel cassette.
0 Poor connection of air bag harness.
0 Short circuit across air bag terminals.
Fault Diagnosis
1. Resistance - check
. Disarm the SRS system and disconnect the driver-side air bag.
rn Disconnect DM and remove plastic locking wedge from black harness connector.
. Measure resistance across harness connections to driver-side air bag, wires RP and KN.
. Does resistance value indicate open circuit.
Yes
- Proceed to step 2.
No - Proceed to step 3.
2. Diagnostic Module -check
Install air bag simulator in place of cable reel cassette at steering column base.
. Re-connect DM.
. Switch on the ignition and wait 30 seconds.
rn Is code 34 still present ?
Yes - Renew DM.
No - Examine shorting bar on driver-side air bag connector for correct operation, rectify if necessary. Renew air bag
module if shorting bar is functioning correctly.
3. Harness -check
. Measure resistance across harness connections to driver-side air bag, wires RP and KN.
. Does resistance value indicate open circuit 7
Yes -
. Examine shorting bar on cable reel cassette connector for correct operation, rectify if necessary.
. Renew cable reel cassette if shorting bar is functioning correctly.
NO -
Inspect harness wiring, cable reel cassettes and terminals for short circuit. Rectify as necessary.
4. On completion
. Arm and verify the SRS system.

Electrical n
15.2 INSTRUMENTS
15.2.1 Introduction
The instrument pack is a self-contained, removable unit, which incorporates all the main display gauges and warning
indicators that are used to present vehicle condition information. The instrument pack is programmed during vehicle
build, to match the vehicle's individual requirements using 'Programmable Electronic Control Units System'
(PECUS). This is achieved via the diagnostic communication line, and therefore, should be renewed like-for-like. The primary
function of the instrument display is to provide the driver with information usual to normal driving requirements. The
secondary function is to display trip computer information.
The trip computer functions are selected via the steering column stalk switch
(LH). The messages are displayed in the
following order:
Odometer
- Distance - Range - Fuel Used -Average Fuel -Average Speed - Instant Fuel - Odometer (return).
Two trip computer switches, 'Reset' and 'Odo', are incorporated into the facia switch panel.
Instrument pack information is received from sensors positioned
at various locations about the vehicle (Fig. 1, follow-
ing page) via one of the two multi-pin sockets located at the rear of the instrument pack.
Information concerning vehicle condition and operation is displayed in one of three ways:
0 Information necessary to confirm normal vehicle operation: road speed, engine speed, oil pressure, battery
condition, fuel level, coolant temperature. This information is displayed using analogue gauges.
0 Information indicating the presence of a hazard/fault condition (low oil pressure/door open etc.) or operational
action (indicator flashing / headlamp full beam 'on' etc.). This information is provided by twenty two warning
lampsltell-tales, arranged in four groups; two groups of seven at the left and right sides of the instrument pack
and two groups of four
at the bottom of the instrument pack.
0 A Liquid Crystal Display (LCD) is located at the bottom-centre of the instrument pack and is normally used to
display the odometer reading, but it can also be used to display SRS fault conditions and trip computer informa-
tion such as vehicle speed, fuel usage and distance travelled.
0
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15.2.3 COMPONENT DESCRIPTION
15.2.3.1 Speedometer
The speed indication input signal, sent as a pulse rate, is generated by an open collectortransistor within the ABS con- trol module. The instrument pack converts the frequency of this signal to drive the speedometer and to provide two
road speed outputs:
Speed output
1 (pin 2,48 way connector)
This output is connected to the radio head unit, security control module and the power steering module.
Speed output 2 (pin
3,48 way connector)
This output is connected to the body processor unit, cruise control control module, air conditioning control module
and the engine management system.
15.2.3.2 Tachometer
The tachometer input, all engine variants, is provided by the engine management control module. When the engine
is running the control module generates three high state pulses per engine revolution.
15.2.3.3
This signal comes direct from the variable resistance type oil pressure sensor, mounted on the engine. The sensor
resistance values range from 75Q (8 Bar) to 330Q (0 Bar).
When the gauge reaches
a pre-determined reading the instrument pack illuminates the warning light.
Engine Oil Pressure and Warning lamp
15.2.3.4 Engine Coolant Temperature
This signal comes direct from the coolant temperature sensor (variable resistance type), mounted on the engine. The
sensor resistance values range from 34Q (hot) to 241Q (cold), when disconnected from the vehicle.
Note: The coolant temperature gauge is calibrated to indicate at approximately 'Normal' for a wide range of normal
engine operating temperatures.
15.2.3.5 Fuel Tank level Gauge and Warning lamp
This signal (pin 20,24-way connector) comes direct from the variable resistor type fuel level sensor. The sensor resis- tance values range from 80 ohms (full tank) to 900 ohms (empty tank).
When the gauge reaches a pre
-determined reading, the instrument pack illuminates the warning lamp.
15.2.3.6
Battery voltage is displayed on the gauge by measuring the ignition voltage.
The red charge warning lamp will illuminate if either the voltage is too low (below
10.5V) or too high (above 15.5V). In addition, the generator provides a low signal to the instrument pack (pin 9,48-way connector) when battery charging
is unsatisfactory.
Battery Voltage Gauge and Warning lamp
15.2.3.7 Liquid Crystal Display
A single line, six digit, 7 segment display with six trip function flags used for odometer, trip computer and driver mess- ages.
!Y,Q&: If the instrument pack has not been PECUS programmed, the back illumination of the LCD will not switch on.
Check that a PECUS label is attached to the back of the pack.
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SPEED CONTROL
System Description
0 15.3 15.3.1
The speed control system provides an automatic cruise facility, allowing a constant speed to be maintained without
accelerator pedal operation. The system comprises the following components:
0 Electronic control unit
0 Vacuum dump valve
0 Control valve
0 Vacuum pump
0 Mechanical throttle linkage and bellows
0 Selection switch
0 Brake and clutch pedal switches
On selection of speed control, via the switches mounted on the driver's side fascia, the vacuum dump valve, pump and
control valve will energize, creating
a partial vacuum in the bellows assembly. The bellows assembly acts upon the
throttle linkage to adjust throttle position, maintaining vehicle speed at the value when control is selected.
Speed control is determined by the Speed Control Control Module
(SC CM) which monitors a speed signal delivered
from the instrument pack (initially from the ABS rear LH wheel speed sensor) to determine vehicle speed.
Speedcontrol isdisabled, returning control tothedriver,
byoperationofthevacuumdumpvalve,ifanyofthefollowing situations occur: 0
0 Braking
0 Clutch operation (3.2 / 4.0 litre manual transmission vehicles only)
o Drive de-select ie P, N or R (automatic transmissions only, both electronic and hydraulic)
0 Traction control system (where fitted) in operation
0 Rapid speed reduction without braking input, ie double brake switch failure
0 Actual speed drop to 3/4 of cruise setting (eg when towing excessive loads under adverse conditions)
0 Vehicle speeds below w 25 mph
0 Ignition OFF
0 De-selection at switch controls
15.3.2 COMPONENT DESCRlPTlO NS
15.3.2.1 Electronic Control Module
The Speed Control Control Module (SC CM), located behind the fascia, adjacent to the steering column, provides sys- tem control and an interface to external input signals from the instrument pack, gear selector module, traction control
system, control switches, and foot pedal switches. The set speed value is retained in SC CM memory and continuously
compared to actual vehicle speed. Adjustments are made, as necessary, to maintain set speed by control of the vac- uum pump and control valve. Connections to the SC CM are listed in the table on page 3.
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15.4 DRIVER ERGONOMICS
15.4.1 System Description
Adjustment of the seats, steering column and exterior rear view mirrors position is effected by means of control
switches. The switches maintain the adjustment facility while depressed, movement ceasing when the switch is re- leased.
Manual adjustment can be achieved either with the ignition key in place or with the driver‘s door open, or having been
closed within the last
30 seconds.
The system offers the following facilities:
Entry
/ Exit mode; an automatic seat /column position setting for ease of driver entry into / exit from the vehicle.
Driving position set; automatic recall of up to three preferred settings.
Passenger seat set; automatic recall of up to three preferred settings.
Remote recall; automatic recall of up to two memory positions from
a remote transmitter (in key fob).
Reverse mirror dip; automatic adjustment of passenger rear view mirror when reversing.
U: Vehicles intended for the Japanese market are fitted with an additional ‘fold away’ mirror function. This func- tion allows mirrors to fold flat against the car when parking in enclosed areas.
15.4.1.1 Entry/ Exit Mode
Entry / Exit mode is designed to give easier vehicle entry and exit for the driver. The facility is selected by positioning
the mode switch, located on the LH side of the column cowl, to ‘auto’ which designates the current seat / column posi- tion, ie driving positions, as the memorized position. On removal of ignition key or opening of driver‘s door, with igni- tion key still in place, the driver’s seat will move to the rear (current position allowing) and the column will adopt ‘tilt
away’ mode automatically creating additional space for driver exit
/ entry. Insertion of key in ignition or closure of
driver‘s door (with ignition key in place) returns seat / column positions to the memorized (previous) position.
Operation of eitherthe brake pedal or
seat/column manual controls during entry/exit mode execution will abort posi- tional adjustments. Setting the mode switch to OFF disables operation of entry / exit mode.
15.4.1.2 Driving Position Set
Setting of seat, column and external rear view mirrors to preferred driving position is available using the memory but- tons located on the drivers door switch pack. With the ignition key in place enter settings to be memorized as follows:
Adjust seat, column and mirrors to desired positions.
Press the ’memory’ button
so that it becomes illuminated.
Press button
1,2 or 3 to store configuration within four seconds of memory button operation. Memory light will extin- guish and a chime will sound, indicating procedure complete.
The above procedure may be repeated two more times until each button
(1,2 & 3) has a preferred position stored in
memory, accommodating different driver settings. Operation of any push-button (1,2 or 3) will re-position seat col-
umn and mirrors to the stored settings.
Memory recall will operate under the following conditions:
. Ignition key in and gear selector in park.
8 Ignition key in and handbrake on.
8 Ignition key out and driver’s door open (or having been closed within the last 30 seconds).
Re
-setting the preferred position on any setting button automatically erases previously stored information. Memory
information is not erased if power supply to the seat and column / mirror control modules is lost (e.g. battery discon- nected).
15.4.1.3 Passenger Seat Set
The procedure for setting and recalling a preferred passenger seat position is identical to that for a driving position.
Memory recall will only operate with ignition key in auxiliary position or passenger door open, or having been closed
within the last
30 seconds.
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15.4.4 STEERING COLUMN /MIRROR
The steering column / mirror adjustment system comprises the following components:
0 Column tilt motor; up / down
0 Column reach motor; fore / aft
0 Column joystick switch; multi-directional
0 Driver’s mirror motors; horizontal and vertical movement
0 Passenger’s mirror motors; horizontal and vertical movement
0 Mirror joystick switches; driver and passenger - multi-directional
0 Column Mirror Control Module (C / M CM)
15.4.4.1 Column Motors
Thetwo column position adjustment motorsare mounted on the column as embly (one laterally d
one transversely)
allowing both vertical and reach distance adjustment. Each motor unit incorporates a potentiometer which provides
directional movement position control via feedback voltage variations to the
C / M CM. Positional variations are acti- vated by the C / M CM in response to signals from the joy-stickswitch mounted on the left-hand side of the column.
15.4.4.2
The column joy-stickswitch provides control of the column position in all directions. Adjustment of theswitch position
will result in a corresponding movement of the column. This switch also allows the selection of ‘Auto Mode’to enable
the Exit / Entry Mode facility.
Column Joy-stick Switch (Fig. 1 inset)
1. Tilt motor 2. Flexible coupling
3 lanition switch
1
J86-1904
Ifeach motor
Fig. 1 Steering Column Assembly 4
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