1994 JAGUAR XJ6 traction control

Electrical D ~
Ignition
+ve feed
Ignition +ve switched supply output I 01 03
06 Speed signal input
09 Traction Control input
10 Control valve control output
11 Ground
12 Ignition +ve input
14
15 ~
Stop
lamp input
17
1 Control switches input
18
j Gear select input
' Dump valve control output ~
20 I Vacuum
pump control output
15.3.2.2 Speed Control Module Pins
1 Pin No 1 Description I Comment
0
Feed to vacuum pump /control valve unit and
dump valve
via brake and clutch switches (or link)
0
0
1 10
A
11 'I n n 01 *O
I" " 1:
J86 1879
Fig. 1 Speed Control Module multi-pin Connector
15.3.2.3 Vacuum Pump /Control Valve Unit
The vacuum pump / control valve unit is located under the hood, behind the LH headlamp. When adjustment of the
throttle position is required, the pump and valve are 'pulsed' on/off by the SC CM to achieve the required vacuum and
hence vehicle speed.
15.3.2.4 Pressure Release Valve
The pressure release (or dump) valve is located adjacent to the vacuum pump /control valve module and opens, vent- ing system air pressure to atmosphere, when speed control is disabled.
X300 EDM 15.3 - 3 Issue 1 August 1994

0 15.3.3 SYSTEM FLOW CHARTS
Systematic fault diagnosis of the speed control system cannot be accurately achieved by attempting to simulate actual
driving conditions. The system can only be reliably and safely tested using Jaguar Diagnostic Equipment.
15.3.4 DIAGNOSTIC SUB-ROUTINES
The following information details possible fault conditions, causes and remedies.
components are covered in Pin-point Tests. Detail test procedures
for
Fault: System inoperative
Possible causes:
1. Fuse FIO (LH 'A' post base fuse-box) blown.
2. Pneumatic circuit fault (ie vacuum leak)
3. Brake switch fault.
4. Clutch switch or link fault. Gear position input fault (automatic transmission only).
5. Harness wiring or connector faulty.
6. Set switch faulty.
7 Paddle switch faulty
8. Traction control input high.
9. Road speed input missing.
10 Dump valve failure.
11 Vacuum pump 1 control valve unit failure.
Remedy: 1. Examine fuse F10, if blown determine reason for failure and renew.
2. Examine all pipework, connections and components for damage or
disconnections, repair
or renew as necessary.
3. Check brake switch operation, renew if necessary.
4. Check clutch switch operation (manual transmission) or link connection I position input
(automatic transmission), renew if necessary.
5. Examine harness wiring. Examine connectors for corroded, damaged or distorted pins.
6. Check set switch operation and wiring, renew if necessary.
7. Check paddle switch operation and wiring, renew if necessary.
8. Examine harness wiring between SC CM and ABS / TC CM, check ABS /TC CM fault
diagnosis.
9. Examine harness wiring between SC CM and instrument pack, check pack fault diagnosis.
10 Renew faulty valve.
11 Renew faulty unit
0
Fault:
Cause:
1. Clutch pedal switch or harness failure.
Clutch pedal operation does not disable system
1. Remedy: Check switch operation and wiring connections. Repair or renew switch / wiring
as necessary.
Fault:
Cause:
1, Faulty signal from gear selection module.
Remedy: 1. Examine transmission fault diagnosis.
Neutral gear selection does not disable system (automatic transmissions only)
2.
2.
Harness wiring or connector fault
Examine harness between gear selection module and SC
CM pin 18.
X300 EDM 15.3 - 5 Issue 1 August 1994

7. Gear position input
a. Examine harness wiring, checking continuity between SC CM pin 18 and transmission decoder module
(6 cylinder) or linear switch (12 cylinder)
b. Examine transmission fault diagnosis.
8. Road speed input
a. Examine harness wiring, checking continuity between SC CM pin 6 and instrument pack.
b. Examine instrument pack fault diagnosis.
9. Traction control input
a.
b.
Examine harness wiring, checking continuity between SC CM pin 9 and ABS TC J CM.
Examine ABS TC
J CM fault diagnosis.
1
1. Speed Control Control Module (SC CM) 7. Dump Valve
2. Clutch Switch J Link 8. Control Valve / Pump Unit
3. Brake Switch
9. Gear Position Module 4. LH 'A' Post Base Fuse-box 10. ABS Control Module
5. Switch Pack 11. Instrument Pack 6. Column Switchgear Dimmer
Fig. 1 Gear Position, Road Speed and Traction Control Inputs
Issue 1 August 1994 15.3 - 11 X300 EDM