2010 JAGUAR XFR boot

Published: 11-May-2011
Fuel Charging and Controls - V8 S/C 5.0L Petrol - Fuel Charging and Controls
Diagnosis and Testing

Principles of Operation

For a detailed description of the fuel charging and controls system and operation, refer to the relevant Description and
Operation section of the workshop manual. REFER to:

Fuel Charging and Controls (303-04D Fuel Charging and Controls - V8 5.0L Petrol, Description and Operation), Fuel Charging and Controls (303-04D Fuel Charging and Controls - V8 5.0L Petrol, Description and Operation), Fuel Charging and Controls (303-04D Fuel Charging and Controls - V8 5.0L Petrol, Description and Operation), Fuel Charging and Controls (303-04E Fuel Charging and Controls - V8 S/C 5.0L Petrol, Description and Operation), Fuel Charging and Controls (303-04E Fuel Charging and Controls - V8 S/C 5.0L Petrol, Description and Operation), Fuel Charging and Controls (303-04E Fuel Charging and Controls - V8 S/C 5.0L Petrol, Description and Operation).
Inspection and Verification


CAUTION: Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not
guarantee confirmation of a fault and may also cause additional faults in the vehicle being checked and/or the donor vehicle.


NOTE: Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage.

Visual Inspection
Mechanical Electrical
Fuel level
Fuel leaks
Damaged fuel lines
Damaged push connect fittings
Fuel contamination/grade/quality
Throttle body
Damaged fuel tank filler pipe cap
Damaged fuel tank filler pipe
Fuses
Loose or corroded electrical connectors
Harnesses
Sensor(s)
Engine Control Module (ECM)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to
the next step.

4. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for
Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.

Symptom Chart

Symptom Possible Causes Action Engine cranks, but does not
fire
Engine breather system
disconnected/restricted
Ignition system
Fuel system
Electronic engine control Ensure the engine breather system is free from restriction
and is correctly installed. Check for ignition system, fuel
system and electronic engine control DTCs and refer to the
relevant DTC Index Engine cranks and fires, but
will not start
Evaporative emissions purge
valve
Fuel pump
Spark plugs
HT short to ground (tracking)
check rubber boots for
cracks/damage
Ignition system Check for evaporative emissions, fuel system and ignition
system related DTCs and refer to the relevant DTC Index Difficult cold start
Engine coolant level/anti-
freeze content
Battery
Electronic engine controls
Exhaust Gas Recirculation
(EGR) valve stuck open
Fuel pump Check the engine coolant level and condition. Ensure the
battery is in a fully charged and serviceable condition.
Check for electronic engine controls, engine emissions, fuel
system and evaporative emissions system related DTCs
and refer to the relevant DTC Index www.JagDocs.com

Published: 11-May-2011
Engine Ignition - V8 5.0L Petrol/V8 S/C 5.0L Petrol - Engine Ignition
Diagnosis and Testing

Principles of Operation

For a detailed description of the engine ignition system and operation, refer to the relevant Description and Operation section
of the workshop manual. REFER to: (303-07B Engine Ignition - V8 5.0L Petrol/V8 S/C 5.0L Petrol)

Engine Ignition (Description and Operation), Engine Ignition (Description and Operation), Engine Ignition (Description and Operation).
Inspection and Verification


CAUTION: Diagnosis by substitution from a donor vehicle is NOT acceptable. Substitution of control modules does not
guarantee confirmation of a fault and may also cause additional faults in the vehicle being checked and/or the donor vehicle.


NOTE: Check and rectify basic faults before beginning diagnostic routines involving pinpoint tests.

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical and electrical damage.

Visual Inspection
Mechanical Electrical
Engine oil level
Cooling system coolant level
Fuel level
Fuel contamination/grade/quality
Exhaust gas recirculation (EGR) valves
Fuses
Wiring harness
Loose or corroded electrical connectors
Ignition coils
Sensor(s)
Engine Control Module (ECM)
Transmission Control Module (TCM)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to
the next step.

4. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for
Diagnostic Trouble Codes (DTCs) and refer to the DTC Index.

Symptom Chart

Symptom Possible Causes Action Engine cranks, but does not
fire
Engine breather system
disconnected/restricted
Ignition system
Fuel system
Electronic engine control Ensure the engine breather system is free from restriction
and is correctly installed. Check for ignition system, fuel
system and electronic engine control DTCs and refer to the
relevant DTC Index Engine cranks and fires, but
will not start
Evaporative emissions purge
valve
Fuel pump
Spark plugs
HT short to ground (tracking)
check rubber boots for
cracks/damage
Ignition system Check for evaporative emissions, fuel system and ignition
system related DTCs and refer to the relevant DTC Index Difficult cold start
Engine coolant level/anti-
freeze content
Battery
Electronic engine controls
Exhaust Gas Recirculation
(EGR) valve stuck open
Fuel pump
Purge valve Check the engine coolant level and condition. Ensure the
battery is in a fully charged and serviceable condition.
Check for electronic engine controls, engine emissions, fuel
system and evaporative emissions system related DTCs
and refer to the relevant DTC Index

Visual Inspection

Mechanical Electrical
Low/contaminated fuel
Fuel supply/return line(s)
Fuel tank and filler pipe
Fuel leak(s)
Fuel filler cap
Fuel filter
Push connect fittings
Fuel pump
Fuses
Links
Relays
Fuel Pump Driver Module (FPDM)
Fuel pump module
Sensor(s)
Engine control module (ECM)
Rear Junction Box (RJB)
Restraints Control Module (RCM)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to
the next step

4. If the cause is not visually evident, verify the symptom and refer to the Symptom Chart, alternatively check for
Diagnostic Trouble Codes (DTCs) and proceed to the DTC Index

Symptom Chart

Symptom Possible Causes Action Engine cranks, but does not
fire
Engine breather system
disconnected/restricted
Ignition system
Fuel system
Electronic engine control
Ensure the engine breather system is free from
restriction and is correctly installed
Check for ignition system, fuel system and electronic
engine control DTCs and refer to the relevant DTC
Index Engine cranks and fires, but
will not start
Evaporative emissions purge
valve
Fuel pump
Spark plugs
HT short to ground (tracking)
check rubber boots for
cracks/damage
Ignition system
Check for evaporative emissions, fuel system and
ignition system related DTCs and refer to the
relevant DTC Index Difficult cold start
Engine coolant level/anti-
freeze content
Battery
Electronic engine controls
Fuel pump
Purge valve
Check the engine coolant level and condition
Ensure the battery is in a fully charged and
serviceable condition
Check for electronic engine controls, engine
emissions, fuel system and evaporative emissions
system related DTCs and refer to the relevant DTC
Index Difficult hot start
Injector leak
Electronic engine control
Purge valve
Fuel pump
Ignition system
Check for injector leak, install new injector as
required
Check for electronic engine controls, evaporative
emissions, fuel system, ignition system and engine
emission system related DTCs and refer to the
relevant DTC Index Difficult to start after hot
soak (vehicle standing,
engine off, after engine has
reached operating
temperature)
Injector leak
Electronic engine control
Purge valve
Fuel pump
Ignition system
Check for injector leak, install new injector as
required
Check for electronic engine controls, evaporative
emissions, fuel system, ignition system and engine
emission system related DTCs and refer to the
relevant DTC Index Engine stalls soon after start
Breather system
disconnected/restricted
ECM relay
Electronic engine control
Ignition system
Air intake system restricted
Air leakage
Fuel lines
Ensure the engine breather system is free from
restriction and is correctly installed
Check for electronic engine control, ignition system
and fuel system related DTCs and refer to the
relevant DTC Index
Check for blockage in air filter element and air
intake system
Check for air leakage in air intake system Engine hesitates/poor
acceleration
Fuel pressure, fuel pump,
fuel lines
Injector leak
Air leakage
Check for fuel system related DTCs and refer to the
relevant DTC Index
Check for injector leak, install new injector as
required www.JagDocs.com

NO SPEECH
DETECTED None
Jaguar Voice system is expecting a voice
command . Repeat required voice command. STORING None
Jaguar Voice system is storing input telephone information. None COMMAND
CANCELLED None
Jaguar Voice button has been pressed
and held. Previous command cancelled. SEARCHING None
Jaguar Voice system is searching for requested information from phone book. None HOLD BUTTON TO CANCEL None
Jaguar Voice system has requested a
command to be cancelled. None FUEL LEVEL LOW
Amber warning triangle
illuminated LCD. Fuel level in fuel tank has fallen below
low fuel warning limit. Replenish fuel tank. FUEL PUMP
SYSTEM FAULT Amber warning triangle
illuminated LCD. Fuel pump or FPDM fault has occurred.
Investigate cause of fault. Interrogate
ECM for faults and diagnose using an approved Jaguar Diagnostic System. WASHER FLUID
LOW Amber warning triangle
illuminated LCD. Fluid level has fallen below low level
switch in windshield washer reservoir. Replenish reservoir. DOOR OPEN
Red text is illuminated in
LCD and vehicle view Door is open or incorrectly closed. Close open door. showing open luggage
compartment lid is
displayed. BOOT OPEN
Red text is illuminated in
LCD and vehicle view Luggage compartment lid is open or incorrectly closed. Close open luggage compartment lid. showing open door location
is displayed. COLUMN ADJUST None
Manual column adjust has been selected
on steering column adjustment switch. None COLUMN ADJUST
AUTO None
Automatic column adjust has been
selected on steering column adjustment
switch. None MEMORY 1 / 2 / 3 / 4 SETTINGS
RECALLED None
Memory button has been pressed to
recall memory positions for seat, steering column and mirrors. None MEMORY 1 / 2 / 3 / 4 SETTINGS
SAVED None
Memory has been saved for one of the
memory button positions. None SEAT BELT
MINDER None
Engine has been started and driver
and/or front passenger seat belt has not
been fastened. Fasten seat belt(s). CHECK
PEDESTRIAN
SYSTEM Red warning triangle
illuminated in LCD. A fault has occurred with the pedestrian
protection system. Investigate cause of fault. Interrogate
pedestrian protection system control
module for faults and diagnose using
an approved Jaguar Diagnostic System. INERTIA SWITCH TRIPPED Amber warning triangle
illuminated LCD. Message appears when the crash status
signal from the RCM (restraints control
module) changes to crash detected or a
fault in the restraints system prevents
the message from being transmitted. RCM can be rest with an ignition on/off cycle. If fault has occurred, then
investigate cause of fault and
interrogate the RCM for faults and diagnose using an approved Jaguar
Diagnostic System. VALET MODE None
Confirmation that valet mode has been
entered. None VEHICLE ARMED None
Confirmation that alarm and
immobilization has been achieved. None SMART KEY NOT
FOUND PLEASE
INSERT IN SLOT Red warning triangle
illuminated in LCD. Smart key has not been detected by the
passive system inside the vehicle. Smart key not present in vehicle. May
be caused by a flat smart key battery.
Replace internal battery in smart key.
May also be due to a communications problem. CHECK SMART
KEY None The smart key detected is not the
correct smart key for the vehicle. Use the correct smart key coded to the
vehicle. REMOVE SMART
KEY None
Smart key is in the start control module
and has been recognized by the passive
start system. Remove smart key from the start
control module. SMART KEY
BATTERY LOW None
Battery voltage in smart key is
becoming low, resulting in a decrease in
effective range of the smart key
transmitter. Replace smart key internal battery. PRESS BRAKE
WHEN STARTING None The stop/start button has been pressed
without the brake pedal depressed. This
will turn on the ignition power mode 6. To start engine, press brake pedal,
then press stop/start button. GEARBOX NOT IN
PARK None The transmission is not in the 'park'
position. Engine starting will be prohibited until 'park' is selected. Put transmission in the park position. www.JagDocs.com

Symptom Chart - iPOD® Related Faults
Symptom Possible Cause Action iPOD® inoperative
iPOD® configured or
connected incorrectly
If iPOD® playback is faulty but USB playback operates
normally, then follow diagnostic procedures as
specified in pinpoint test A GO to Pinpoint Test A. iPOD® does not operate and
in-car display shows "99" on
the screen
The connected iPOD®
unit has crashed or frozen
See diagnostic procedures as specified in pinpoint test
A1 "Check The Operation Of The iPOD®" below GO to
Pinpoint Test A.
The connected iPOD®
unit's battery is flat and
requires charging
The connected iPOD®
unit's battery is not
holding charge and
requires replacement
See diagnostic procedures as specified in pinpoint test
A2 "Check The iPOD® Battery" below GO to Pinpoint
Test A.
The iPOD® unit is not
compatible with the audio
input control module
See diagnostic procedures as specified in pinpoint test
A4 "Check The iPOD® Is Compatible With The Audio
Input Control Module" below GO to Pinpoint Test A. iPOD® playback drops out and
system reverts to radio input
USB input or iPOD® input
faulty
First check operation of iPOD® playback. If iPOD®
operates normally but USB playback is faulty, then
follow diagnostic procedures as specified in pinpoint
test B GO to Pinpoint Test B. If iPOD® playback is faulty but USB playback operates
normally, then follow diagnostic procedures as
specified in pinpoint test A GO to Pinpoint Test A.
The connected iPOD®
unit has crashed or frozen
See diagnostic procedures as specified in pinpoint test
A1 "Check The Operation Of The iPOD®" below GO to
Pinpoint Test A.
The connected iPOD®
unit's battery is flat and
requires charging
The connected iPOD®
unit's battery is not
holding charge and
requires replacement
See diagnostic procedures as specified in pinpoint test
A2 "Check The iPOD® Battery" below GO to Pinpoint
Test A.
The auxiliary input unit is
faulty
See diagnostic procedures as specified in pinpoint test
A6 "Check The Operation Of The Auxiliary Input Unit"
below GO to Pinpoint Test A. iPOD® unit will not charge
when connected to the audio
input control module
The iPOD® unit is not
compatible with the audio
input control module
See diagnostic procedures as specified in pinpoint test
A4 "Check The iPOD® Is Compatible With The Audio
Input Control Module" below GO to Pinpoint Test A.
The iPOD® dock cable is
not securely installed
The iPOD® dock cable is
faulty
See diagnostic procedures as specified in pinpoint test
A3 "Check The iPOD® Is Charging When Connected To
The Audio Input Control Module" below GO to Pinpoint
Test A. iPOD® unit keeps cutting out
and rebooting
The iPOD® unit is not
compatible with the audio
input control module
See diagnostic procedures as specified in pinpoint test
A4 "Check The iPOD® Is Compatible With The Audio
Input Control Module" below GO to Pinpoint Test A.
The iPOD® dock cable is
not securely installed
The iPOD® dock cable is
faulty
See diagnostic procedures as specified in pinpoint test
A3 "Check The iPOD® Is Charging When Connected To
The Audio Input Control Module" below GO to Pinpoint
Test A.
The connected iPOD®
unit's battery is flat and
requires charging
The connected iPOD®
See diagnostic procedures as specified in pinpoint test
A2 "Check The iPOD® Battery" below GO to Pinpoint
Test A.

DTC Description Possible Cause Action B116515
Left Front
Puddle Lamp
Output
Left front puddle lamp
control circuit - short to
power, open circuit Carry out any pinpoint tests associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and test left front puddle lamp control circuit
for short to power, open circuit B116611
Right Front
Puddle Lamp
Output
Right front puddle lamp
control circuit - short to
ground Refer to the electrical circuit diagrams and test right front
puddle lamp control circuit for short to ground B116615
Right Front
Puddle Lamp
Output
Right front puddle lamp
control circuit - short to
power, open circuit Carry out any pinpoint tests associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and test right front puddle lamp control circuit
for short to power, open circuit B111E11
Boot/Trunk
Lamps
Luggage compartment lamp
control circuit - short to
ground Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check luggage compartment lamp control
circuit for short to ground B111E15
Boot/Trunk
Lamps
Luggage compartment lamp
control circuit - short to
power, open circuit Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check luggage compartment lamp control
circuit for short to power, open circuit B112412
Lamp Fade
Control
Interior lamp fade control
circuit - short to power Refer to the electrical circuit diagrams and check interior lamp
fade control circuit for short to power B113C12
Hazard Switch
Illumination
Hazard switch illumination
control circuit - short to
power Refer to the electrical circuit diagrams and check hazard switch
illumination control circuit for short to power B1A8596
Ambient Light
Sensor
Light sensor internal
electronic failure Check and install a new sensor as required U201012
Switch
Illumination
Switch/interior illumination
PWM supply circuit - short to
power Refer to the electrical circuit diagrams and check switch/interior
illumination PWM supply circuit for short to power U201014
Switch
Illumination
Switch/interior illumination
PWM supply circuit - short to
ground, open circuit Refer to the electrical circuit diagrams and check switch/interior
illumination PWM supply circuit for short to ground, open circuit

DTC Description Possible Cause Action B100951
Ignition
Authorisation
Faulty instrument cluster
Target SID re-synchronisation
error following programming
CAN fault Check ignition, power and ground supplies to CJB and
instrument cluster. Re-synchronize ID by re-configuring
the instrument cluster as a new module. Check CAN
communications between instrument cluster and tester B100962
Ignition
Authorisation
Low speed CAN fault
CJB fault
Instrument cluster fault
Incorrect module installed
(CJB/Instrument cluster)
Target SID synchronisation
error following re-programming
Noise/EMC related error Check CAN communications between CJB and instrument
cluster. Check ignition, power and ground supplies to CJB
and instrument cluster. Confirm correct module is
installed. Re-synchronise ID by re-configuring the
instrument cluster as a new module. Check CAN network
for interference/EMC related issues B100963
Ignition
Authorisation
CJB fault
Low speed CAN fault
Instrument cluster fault
Low battery voltage <9V Check Power and Ground supplies to CJB and instrument
cluster. Check CAN communications between CJB and
instrument cluster. Check battery is in fully charged and
serviceable condition, refer to the battery care manual B100964
Ignition
Authorisation
CJB fault
Low speed CAN fault
Instrument cluster fault Check power and ground supplies to CJB and instrument
cluster. Check CAN communications between CJB and
instrument cluster B102B67 Passive Key
CJB fault
Low speed CAN fault
Remote Keyless Entry (RKE)
module fault
Write target SID
synchronisation error following
re-programming Check power and ground supplies to CJB and RKE
module. Check CAN communications between CJB and
RKE module. Re-synchronise ID by re-configuring the RKE
module as a new module B102B87 Passive Key
CJB fault
Low speed CAN fault
RKE module fault
Key fob battery low/battery
contact issue
Interference from other RF
signal
EMC/noise
Receiver fault
Receiver not programmed
correctly
Serial communications fault
(between receiver and RKE
module)
Key fault
Passive antenna fault
Confirm placement of key
within vehicle Check power and ground supplies to CJB, RKE module
and receiver. Check CAN communications between CJB
and instrument cluster. Check key fob battery. Confirm
vehicle surroundings, move vehicle. Check CAN network
for interference/EMC related issues. Disconnect battery,
then re-connect - confirm operation by re-programming
keys. Check serial circuit between receiver and RKE
module. Confirm spare key works. Refer to the electrical
circuit diagrams and test circuits to all 3 antennas. Check
whereabouts of key B108413
Boot/Trunk Motor
Close Switch
Trunk latch open signal circuit -
open circuit Refer to the electrical circuit diagrams and check trunk
latch open signal circuit for open circuit B108783 LIN Bus "A"
Checksum of the received LIN
frame from battery backed
sounder, roof header console,
and/or rain/light sensor is
incorrect Check operation of rain/light sensor by covering sensor or
applying water to screen, install a new sensor as
required B108788 LIN Bus "A"
Bus off. Battery backed
sounder, roof header console,
and/or rain/light sensor LIN
circuit - short to ground, power Carry out any pinpoint tests associated with this DTC
using the manufacturer approved diagnostic system.
Refer to the electrical circuit diagrams and check battery
backed sounder, roof header console, and rain/light
sensor LIN circuit for short to ground, power B108A11 Start Button
Start/Stop switch analogue
input circuits 1 or 2 - short to
ground Refer to the electrical circuit diagrams and check
Start/Stop switch analogue input circuits 1 and 2 for
short to ground www.JagDocs.com

DTC Description Possible Causes Action B10DE15
Low Fuel Warning
Switch
Diesel run-dry switch
analogue input circuit -
short to power, open
circuit Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check diesel run-dry switch analogue input
circuit for short to power, open circuit B111211 Park Aid Ignition
Parking aid ignition
supply circuit - short to
ground Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check parking aid ignition supply circuit for
short to ground B111212 Park Aid Ignition
Parking aid ignition
supply circuit - short to
power Refer to the electrical circuit diagrams and check parking aid
ignition supply circuit for short to power B111511
High Mounted
Stop Lamp
Control
High mounted stop lamp
control circuit - short to
ground Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check high mounted stop lamp control circuit
for short to ground B111611 Left Tail Lamp
Left hand tail lamp
control circuit - short to
ground Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check left hand tail lamp control circuit for
short to ground B111711 Right Tail Lamp
Right hand tail lamp
control circuit - short to
ground Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check right hand tail lamp control circuit for
short to ground B111A11
Number Plate
Lamps
Right hand or left hand
number plate lamp
control circuits - short to
ground Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check right hand and left hand number plate
lamp control circuits for short to ground B111A12
Number Plate
Lamps
Right hand or left hand
number plate lamp
control circuits - short to
power Refer to the electrical circuit diagrams and check right hand and
left hand number plate lamp control circuits for short to power B111A13
Number Plate
Lamps
Right hand or left hand
number plate lamp
control circuits - open
circuit Refer to the electrical circuit diagrams and check right hand and
left hand number plate lamp control circuits for open circuit B111A-15
Number Plate
Lamps - circuit
short to battery
or open
Right or left side licence
plate lamp(s) inoperative
Right or left side licence
plate lamp control
circuits - short circuit to
power, open circuit, high
resistance
Refer to the electrical circuit diagrams and check right
side and left side licence plate lamp control circuits for
short circuit to power, open circuit, high resistance. Repair
wiring harness as required. Clear DTC and retest B111D12
Boot/Trunk Motor
Open
Luggage compartment lid
latch actuator control
circuit - short to power Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check luggage compartment lid latch
actuator control circuit for short to power B111D14
Boot/Trunk Motor
Open
Luggage compartment lid
latch actuator control
circuit - short to ground,
open circuit Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check luggage compartment lid latch
actuator control circuit for short to ground, open circuit B111E11 Boot/Trunk Lamps
Luggage compartment
lamp control circuit -
short to ground Carry out any pinpoint test associated with this DTC using the
manufacturer approved diagnostic system. Refer to the electrical
circuit diagrams and check luggage compartment lamp control
circuit for short to ground B111E12 Boot/Trunk Lamps
Luggage compartment
lamp control circuit -
short to power Refer to the electrical circuit diagrams and check luggage
compartment lamp control circuit for short to power