fuse box JAGUAR XJ6 1994 2.G Electrical Diagnostic Manual

lw Automatic Transmission (AJ16)
SYSTEM VOLTAGE MALFUNCTION - P 1794
The TCM monitors the supply voltage and will log this fault if the voltage is less than 10.5V when the engine speed is
greaterthan 1600rpm. This fault code is unlikelyto becaused by afault within theTCM and assuch thevehicle harness
and fuses etc. should be completely tested before the TCM is condemned.
Possible causes:
. Blown fuses.
. Faulty harness wiring /connections.
Effects:
Transmission default settings adopted.
. MIL illuminated.
Transmission warning lamp illuminated.
. Maximum fluid pressure available.
. Limp home mode applied.
Remedy:
Examine fuse F14 in LH heelboard fuse-box. Renew (if necessary) after determining cause of rupture.
. Repair or renew harness / connector.
KICK-DOWN SWITCH SYSTEM - P 1796
The diagnostic check on the mode switch input is a plausibility check which is performed continuously while in oper- ation. A fault is determined when kickdown is seen when the throttle angle is less than 50%. However a fault will only
be logged if the output speed is greater than 256 rpm. No fault is logged if there is already a throttle signal fault. The
kickdown switch is located on the floor under the accelerator pedal and is operated when the throttle is fully open (ap- prox 90%). It is a normally open switch with one contact permanently to ground and the other is a signal to the TCM.
The signal wire is routed through the bulkhead harness and the gearbox harness to the TCM.
LHD
(FCO19) PIN 2 GROUND PIN 1 KD
SIGNAL
RHD
(CA074) PIN 2 GROUND PIN 1 KD
SIGNAL
Possible causes
. Faulty harness wiring /connections.
. Faulty switch (or switch adjustment).
Effects:
No kickdown facility.
Remedy:
. Repair or renew harness /connector.
. Re-adjust or renew switch.
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0
0
Q
Issue 1 August 1994 24 X300 EDM

Powertrain Automatic Transmission (V12)
Solenoid Valves A and B - Performance /Electrical - PO75 1 / PO753 and PO756 / PO758
Function:
Valve operation monitoring.
Connections: TCM
CCO48/039
CCO48/043
Multi-plug
Connector
GBO
10/002
GBOl0/004
GBO 10/003
(+12V)
Transmission
GB012/001 SOL A
GBOl2/002 SOL B
GB012/003 SUPPLY
Possible causes:
. Faulty valve.
. Faulty harness wiring 1 connectors.
. Blown fuse.
Effects:
9 MIL illuminated.
Second gear selected permanently ie 'Limp Home' mode.
Remedy:
. Renew faulty valve.
Repair or renew harness 1 connectors.
. Renew fuse F14 in LH heelboard fuse-box on determining reason for rupture.
1 1
Solenoid valves -fault codes PO751 / PO753 / PO756 / PO758
1
Fia. 1 JUl3 ~ 1749
&@: * +12V present
only when ignition switched ON
X300 EDM 19 Issue 1 August 1994

Automatic Transmission (V12) Powertrain
Shift Malfunction (Max- Adapt) - PO780
Function:
Transmission internal operation monitoring.
Possible causes:
. Mechanical wear 1 failure.
Effects:
. Harsher shifts.
Remedy:
. Refer to VSM, Section 8.2.
Transmission Component Slipping - PI 739
Function:
Transmission internal operation monitoring.
Possible causes:
Faulty harness wiring /connection.
. Fuse blown.
. Faulty torque converter clutch.
Mechanical wear.
Effects:
. MIL lamp illuminated.
. Harsh shifts.
Remedy:
. Repair or renew harness 1 connector.
Renew fuse F14 in LH heelboard fuse-box on determining reason for rupture.
Refer to VSM, Section 8.2.
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Issue 1 August 1994 20 X300 EDM

Automatic Transmission (V12) - Powertrain
System Voltage Malfunction - P1794
Function:
Battery voltage monitor.
Possible causes:
. Faulty harness wiring /connection.
. Blown fuses.
Effects:
. MIL illuminated.
. Second gear selected permanently ie ‘Limp Home’ mode.
Remedy:
Repair or renew harness I connector.
. Examine fuse F14 and F5 in LH and RH heelboard fuse-boxes respectively.
. Renew (if necessary) after determining cause of rupture.
P5 5
P53
1
I -3---+-2 YR
System supply voltage -fault code PI794
J86 - 1 753 Fig. 1
- Note: * +12V present only when ignition switched ON
X300 EDM ~.
25 Issue 1 August 1994

Steering @
10.3 DIAGNOSTICS
a Fault: Steering light at all times
Cause: 1. No speed signal
2. Wiring fault
Remedy: 1.
2a.
2b. Check
wiring harness continuity between PSCM pin
V and instrument pack
pin
2.
Check voltage between transducer pin 1 (+ve) and ground, with ignition
ON. If 12V is recorded repair or renew harness.
Check wiring between transducer pin
2 (-ve) and OV. If OV is recorded
repair or renew harness.
Fault: Steering heavy at all times
Cause: 1. Fuse blown
2. Wiring fault
Remedy: 1.
2a.
2b.
2c.
2d Examine
fuse F12 in
RH heelboard fuse-box, if blown determine reason for
failure and renew.
Check wiring harness continuity between fuse F12 in
RH heelboard
fuse
-box and PSCM pin V.
Check wiring harness continuity between PSCM pin W1 and transducer
pin 1.
Check wiring harness continuity between PSCM pin W2 and transducer
pin
2.
Check voltage between transducer pin 2 and ground, with ignition ON. If
12V is recorded repair or renew harness and renew PSCM.
Fault:
Cause:
1. Short circuit
Remedy:
Steering becomes heavy during driving until ignition cycled
la.
1 b.
Check resistance between transducer pins 1 and 2. If a value below 7.5f is
recorded renew transducer.
Check resistance of wiring harness between transducer connections. If
short circuit is recorded renew harness.
Note: Operation ofthe PSCM can bechecked using Jaguar Diagnostic Equipment. Generation of input speed signals
and measurement of the resulting current outputs indicate
if PSCM is faulty.
X300 EDM 3 Issue 1 August 1994

Brakes (a)
The input frequency of each sensor signal is translated, by the ABS /TC CM, into a comparable wheel speed. Should
any sensed speed be in excess of 330 km / h the relevant sensor is designated 'faulty' and ABS /TC control disabled.
Similarly ABS/TCcontrol is inhibited (switched off until fault condition is cleared) at speeds up to 40 km/ h whenfre- quency fluctuations are detected that are inconsistent with wheel rotation. At speeds above 40 km / h both systems
are disabled when inconsistencies are detected.
Traction control (where fitted) is achieved by using
a small motor and pulley arrangement to adjust the position of the
throttle flap. Under normal operating conditions the system is enabled by default. Operation of the Traction OFF / ON switch, located on the RH side of the fascia switch pack, disables the system and illuminates the TRACTION OFF lamp
located in the instrument pack.
Control is effected to prevent wheel spin by regulating (reducing) the throttle flap position, irrespective of the acceler
-
ator pedal position, using sensor signal comparisons and applying braking force to the wheel affected. Precise posi- tioning of the flap is achieved by monitoring the position of a throttle position sensor. When traction control is
requested
a gearshift inhibit signal is transmitted to the traction control module and cruise control (if selected) is dis- abled.
1
2
3
4
Battery positive feed (via fuse F7,located in the left-hand 'A' post lower fuse-box).
Battery positive feed (via fuse
F7,located in the right-hand 'A' post lower fusebox).
Gearshift inhibit
- during traction control.
Cruise control inhibit
- during traction control.
5/6 Wheel sensor
- LHF
7/8 Wheel sensor
- RHF
9/10 Wheel sensor
- LHR
Control Module Connections
Control module connections numbering 1 - 28, inclusive, provide the necessary input / output signals to enable the
module to control and monitor ABS / TC operation.
Connections are as follows:
13 Ground
14 Ground
15
16
17
18
19 Not used
20 Brake pedal switch.
21
22
23
24
25
26 Throttle position sensor wiper.
27 Throttle position sensor ground.
28 Diagnostic
IS0 communication bus.
Ignition
feed
- monitoring battery voltage to ignition switch.
Throttle valve actuator motor
- battery voltage reference.
Throttle valve actuator motor switching
-during traction control.
Traction inhibit
- via traction OFF / ON switch.
ABS MIL
- malfunction indicator lamp.
ABS ground
- illuminates ABS MIL lamp if ABS /TC CM connector loose or not fitted.
TC MIL
- malfunction indicator lamp.
RL out
- LHR wheel sensor signal drive pulse to speedometer.
Throttle position sensor
5V supply.
I 1 11/12 1 Wheel sensor - RHR 1
X300 EDM 3 Issue 1 August 1994

Brakes
12.4 SYSTEM FAULT INDICATION
Fault Indication:
ABS MIL lamp is still illuminated after ignition switch on and instrument pack self test.
h:
Possible causes
Fuses blown.
Faulty wheel speed sensor or harness.
Faulty wiring.
Faulty ABS
/ TC CM.
It is likely that theTC MIL lamp and Traction OFF lamp will also illuminate on vehicles with traction control fitted.
Fault Diagnosis
On the first ignition cycle after afault has been sucessfully diagnosed and corrected the vehicle must bedriven to a speed above 20kph (12.5 mile/ h) before warning lamps will extinguish. If lamps remain on after this exer- cise repeat fault diagnosis.
. Check fuses (F7) in battery feed lines and (F16) in ignition line. Battery fuses are located in the left and right hand
. Unbolt 28 way multi-plug connector from ABS / TC CM.
. Measure resistance across each wheel speed sensor.
No - Unplug sensor flying lead and re-measure sensor resistance.
N&:
heelboard fuse boxes. The ignition supply fuse is located in the left hand heelboard fuse box.
Is value measured 1 10052, f 50%?
Rear sensor connectors are located beneath the rear seat. Seat must be removed to gain access to connector.
Forward sensor connectors are located adjacent to the hood catch bracket.
Is value now within range?
Yes
- Examine harness between ABS I TC CM and sensor.
No - Renew sensor.
= Check continuity to ground from ABS 1 TC CM harness connections 13 and 14. If value is much greater than 0.152
renew harness.
. With the ignition switch ON, measure voltage between ABS /TC CM harness connection 14 and connections 1 and 2 respectively. If value is not approximately equivalent to battery voltage renew harness.
. With the ignition switch ON, measure voltage between ABSITC CM harness connections14 and 15. If value is not
approximately equivalent to battery voltage renew harness.
Renew ABS /TC CM if fault is not located during the above procedures.
fault Indication:
ABS MIL lamp illuminates at 20 kph.
m:
Possible Causes
Fuses blown.
Faulty hydraulic module pump
/ motor unit or circuitry.
Faulty ABS
/ TC CM.
Fault Diagnosis
Check fuses.
. Disconnect pump / motor unit and measure resistance across two pin connector. Measured value should be in the
. Unbolt 28-way connector from ABS /TC CM and measure voltage between harness connections1 and 14. If value
. Renew ABS 1 TC CM if fault is not located during the above procedures.
It is IikelythattheTCMILlampandTraction OFFlampwill also illuminateonvehicleswithtractioncontrolfitted.
region of 0.852. Renew unit if excessive resistance or short circuit is recorded.
is not approximately equal to battery volts renew harness.
Issue 1 August 1994 X300 EDM

Climate Control Systems
28-
I llSA I
1.
2.
3.
4.
5.
6.
7.
8.
9.
IO.
11. 12.
13.
14.
15.
21J 20
Instrument pack
Fascia switch pack
Defrost servo.
Air distribution box Solar sensor
Control panel
Centre console
LH blower motor
Water valve
Circulation pump
Coolant temperature sensor
LH front fuse
-box
Circulation pump relay
Ambient temperature sensor
A
/ C compressor
17
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27. 28.
29.
16 1's J86 1767
Compressor clutch relay
Trinary pressure switch
Radiator fan pressure switch
Control module
RH blower motor
Engine control module
Motorized
in-car aspirator
A
/ C isolate relay
RH blower motor high speed relay RH blower motor relay
LH blower motor high speed relay
LH blower motor relay
-
-
Fig. 1 Component Location Diagram
Issue 1 August 1994 2 X300 EDM

Climate Control Systems
14.7.22 BLOWER MOTORS
Disconnect the blower motors (LH & RH) multi-plugs and check motor operation by applying battery voltage (+12V) across pin 5 (+vel and pin 9 (-ve).
Non-functioning of both L H and RH motors *
Cause:
1. Loss of ignition voltage.
Remedy:
1.
2.
*
Examine fuse F12 in RH heelboard fuse-box. If fuse is blown determine reason for failure and renew.
Examine harness wiring from
RH heelboard fuse-box connection CA044/010 to splice CAS53. Repair or renew
wiring as necessary.
This fault will also affect the operation of seat control modules, power steering control module and door mirror
heaters.
Non-functioning of RH blower motor only
Cause:
1. Faulty relay operation.
2. Faulty harness wiring.
Remedy:
1. Ensure 12Vsupply between relay pin 1 and ground.
Ensure continuity between pins 3 and
5 when relay operated.
Ensure relay coil impedance of
7552 to 135Q across pins 1 and 2.
Ensure correct seating of relay on base. Examine pins for damage or deformity.
Check continuity of wiring from fuse F12
(RH heelboard fuse-box) to relay pin 1 and from relay pin 2 to A / CCM
pin 53 (26-way connector).
Check continuity of wiring from fuse
F11 (RH heelboard fuse-box) to relay pin 3, from relay pin 5 to motor pin 5, from motor pin 13 to A / CCM pin 41 (16-way connector), from motor pin 8 to ground and from motor pin 10 to A / CCM pin 42 (16-way connector).
2.
Non-functioning of L H blower motor only
Cause:
1. Faulty relay operation.
2. Faulty harness wiring.
Remedy:
1. Ensure 12V supply between relay pin 1 and ground.
Ensure continuity between pins 3 and
5 when relay operated.
Ensure relay coil impedance
of 7552 to 135Q across pins 1 and 2.
Ensure correct seating of relay on base. Examine pins for damage or deformity.
2. Check continuity of wiring from fuse F12 (RH heelboard fuse-box) to relay pin 1 and from relay pin 2 to A / CCM
pin 66 (26-way connector).
Check continuity of wiring from fuse
F11 (LH heelboard fuse box) to relay pin 3, from relay pin 5 to motor pin 5, from motor pin 13 to A / CCM pin 49 (16-way connector), from motor pin 8 to ground and from motor pin 10 to
A / CCM pin 50 (16-way connector).
X300 EDM 23 Issue 1 August 1994

Electrical
0
NO AIR BAG MIl LAMP
Inoperative lamp Circuit or No Ignition to the Diagnostic Module
Normal Operation
The air bag MIL Lamp is designed to illuminate for approximately six seconds when the ignition is switched ‘on’; this
time has been allocated to prove the MIL Lamp operation.
The DM requires an ignition supply to Pin
1, to energize the air bag MIL Lamp circuit. If the MIL Lamp is open circuit
or the DM does not receive ignition voltage at Pin 1, the MII Lamp will not illuminate.
Open circuit in the
MII Lamp supply will cause the DM to emit five tones, or ‘beeps’ every 30 minutes while ignition
is on. Repair faulty circuitry before further diagnostics.
Possible Causes
0 Bulb blown or faulty wiring in the air bag MIL Lamp circuit.
0 Loss of ignition voltage at DM pin 1.
Fault Diagnosis
1. Ignition voltage -check
8 Disarm the SRS system.
8 Switch on the ignition.
8 Measure the voltage between pin 1 (+vel and pin 3 (-vel of the connector.
8 Battery voltage present, proceed with step 2.
8 Battery voltage not present; open circuit on R / W wire from RH fuse-box or faulty ground at pin 3.
8 Check fuse 17, RH fuse-box.
8 Check the fuse connectors and wiring.
8 Check the ground at pin 3 of the DM connector.
8 Arm and verify the SRS system.
2. MIL Lamp open circuit
8 Renew the DM.
8 Arm and verify the SRS system.
If the MIL Lamp is not illuminated, check the bulb, instrument pack and associated wiring.
Issue 1 August 1994 15.1 - 6 X300 EDM