1998 JAGUAR X308 Fuel pump relay

Pinpoint Tests
DT
C
De
scription
Possib
le Source
Acti
on
P1245Engine

crank signal low
voltage
Starter relay
coil to
ECM/BPM circuit open
circuit
F
or starter relay circuit tests,GO to
Pinpoint Test B.
.
P1246Engine
crank signal high
voltage
Starter relay
coil to ECM/BPM circuit short
circuit to B+ voltage
B
PM failure
F
or starter relay circuit tests,GO to
Pinpoint Test B.
.
P
INPOINT TEST A : CHECK THE
POWER SUPPLY, GROUND AND TRI GGER TO THE STARTER CIRCUIT
•
NOTE: During cranking with the engine disabled, observe the engine cranking speed. A cranking speed as low as 90 rpm
is acceptable, but will be difficult to measure. A degree of discretion must be used as to when an engine is cranking too
slowly.
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1: CHECK

THE VOLT DROP AC
ROSS THE STARTER CIRCUIT
M
easure the volt drop across the circuit between the battery positive terminal and the starter motor
terminal, ST01.
1
Is the vol
t drop greater than 1 volt?
Yes CHECK the battery connections, cable connections at false bulkhead stud connector, and starter
motor. Make sure all connections are in good co ndition and secure. If all connections are sound,
INSTALL a new battery lead.
REFER to Section 414
-0
1 Battery, Mounting and Cables
.
TEST the system
for normal operation.
No GO to A2
.
A2: CHECK
THE VOLT DROP ACROSS
THE STARTER CIRCUIT (CRANKING)
Di
sable the fuel or ignition system to prevent the engine starting.
1

Turn the ignition swi
tch to the CRANK
position.
2
M
easure the volt drop across the circuit between the battery positive terminal and the starter motor
terminal, ST01.
3
Is the vol
t drop greater than 1 volt?
Yes CHECK the battery connections, cable connections at false bulkhead stud connector, and starter
motor. Make sure all connections are in good co ndition and secure. If all connections are sound,
INSTALL a new battery lead.
REFER to Section 414
-0
1 Battery, Mounting and Cables
.
TEST the system
for normal operation.
No GO to A3
.
A3:
CHECK THE GROUND TO THE STARTER MOTOR
Meas

ure the resistance between the engine GROUND lead and the starter motor body.
1

Is th
e resistance greater than 5 ohms?
Yes CLEAN the connection between the starter motor body and it's fittings, recheck the resistance. TEST
the system for normal operation.
No GO to A4
.
A4
: CHECK THE STARTER SIGNAL FROM THE STARTER RELAY
R

emove the fuel pump relay.
1

Di
sconnect the starter motor signal
electrical connector, ST03 (WR).
2
Turn the ignition swi
tch to the CRANK
position.
3
M
easure the voltage between ST03 (WR) and GROUND.
4

Is th
e voltage less than 10 volts?
Yes GO to A5
.
No

INSTALL a new starter motor.
REFER to Starter Motor
-

in t
his section.
TEST the system for normal operation.
A5
: CHECK THE STARTER SIGNAL CIRCUIT FOR HIGH RESISTANCE
R

emove the starter relay.
1

Meas

ure the resistance between the st
arter relay base, pin 05 and ST03 (WR).
2
Diagnostic Trouble Code (D
TC) Index

• NO
TE: When performing electrical voltag
e or resistance tests, always use a digital multimeter (DMM) accurate to 3
decimal places, and with an up-t o-date calibration certificate. When testing resistance, always take the resistance of the
DMM leads into account.
• NOTE: Check and rectify basic faults before beginning diagnostic ro utines involving pinpoint tests.
Sym
ptom Chart
Sy
m
ptom
Possib
l
e source
Acti
o
n
Engine
cranks, but does
not fire
Secu
rit
y system /Immobiliser
engaged
Harness Fue l
system
ECM fault

Contact deal er techni
cal support for
information on security system. Check fuel
system pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For ECM tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Engine cranks and
fi
res, but will not
start
Fu
el pump relay
Fuel

pump
Cyl
i
nder compression loss
(short-term. Refer to bulletin; 303-52)
Engine coolan t
temperature
(ECT) sensor
Spark plugs fouled, gapp
ed
incorrectly
Ignition coil fail
ure(s)
Check f
o
r water ingress into
spark plug wells
HT sho rt to ground (tracking)
check rubber
boots for
cracks/damage
Fo
r fuel pump relay tests,
REFER to: Fuel Charging and Controls
(303
-04

Fuel Charging and Controls, Diagnosis and Testing).
Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For compression loss, REFER to the technical service bulletins. For ECT sensor tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For spark plug tests, GO to Pinpoint Test B.
.
For ign i
tion system tests, GO to Pinpoint Test
A.
.
Diff
icult to start cold
Batt
ery Fuel
pump
Cyl
i
nder compression loss
(short-term. Refer to bulletin; 303-52)
Spark plugs fouled, gapp
ed
incorrectly
F o
r battery information,
REFER to: Battery and Cables
(414
-01 Battery,

Mounting and Cables, Description and Operation).
Check fuel pressure.
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For compression loss, REFER to the technical service bulletins. For spark plug tests, GO to
Pinpoint Test B.
. For ig
nition system tests, GO
to Pinpoint Test A.
.
Diff
icult to start hot
Roc
h
ester valve
Injec
t
or leak
Purge
val
ve
Fue
l
pump
Engine coolan
t
temperature
(ECT) sensor
F or R
ochester
valve test,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For injector leak test, REFER to technical
service bulletins. Check fuel pressure. For evaporative emissions components,
REFER to: Evaporative Emissions
(303
-13
Evaporative Emissions, Diagnosis and Testing).
For ECT sensor tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
D iff
icult to start after hot soak
(vehicle standing after engine has reached operating temperature)
Roc h
ester valve
Injec
t
or leak
Purge
val
ve
Fue
l
pump
Engine coolan
t
temperature
(ECT) sensor
F or R
ochester
valve test,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For injector leak test, REFER to technical service bulletins. Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).

F
or evaporative emissions components,
REFER to: Evaporative Emissions
(30
3-13
Evaporative Emissions, Diagnosis and Testing).
For ECT sensor tests,
REFER to: Electronic Engine Controls
(30
3-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Engine stalls
soon after start
F
uel pump relay
ECM relay


Harness damage Fue

l pump
Engine coolan

t temperature
(ECT) sensor
Fue
l lines
F

uel pressure regulator
Air leakage


Check f
or DTCS. For fuel pump and ECM relay
tests,
REFER to: Fuel Charging and Controls
(30
3-04

Fuel Charging and Controls, Diagnosis and Testing).
Check fuel pressure.
REFER to: Fuel System Pressure Check
(31
0-
00 Fuel System - Genera l Information, General
Procedures).
For ECT sensor tests,
REFER to: Electronic Engine Controls
(30
3-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For fuel line information,
REFER to: Fuel Tank and Lines
(31
0-01 Fuel
Tank and Lines, Description and Operation).
For fuel pressure regulator,
REFER to: Fuel Charging and Controls
(30
3-04

Fuel Charging and Controls, Diagnosis and Testing).
For intake system information,
REFER to: Intake Air Distribution and Filtering

(30
3-12 Intake Air Distribution and Filtering,
Description and Operation).
Engine hesi
tates/poor acceleration
Fue
l pump
Air leakage


F

uel pressure regulator
Fue

l lines
Harness damage Throttl

e sensors
Throttl

e motor
Spark

plugs fouled, gapped
incorrectly
Ignition coil
failure(s)
Check f

or water ingress into
spark plug wells
HT sho
rt to ground (tracking)
check rubber boots for cracks/damage
Exhaus
t gas recirculation (EGR)

(SC only)
Chec
k fuel pressure,
REFER to: Fuel System Pressure Check
(31
0-
00 Fuel System - Genera l Information, General
Procedures).
For intake system information,
REFER to: Intake Air Distribution and Filtering

(30
3-12 Intake Air Distribution and Filtering,
Description and Operation). For fuel pressure regulator,
REFER to: Fuel Charging and Controls
(30
3-04

Fuel Charging and Controls, Diagnosis and Testing).
For fuel lines information,
REFER to: Fuel Tank and Lines
(31
0-01 Fuel
Tank and Lines, Description and Operation).
For throttle position se nsor and throttle motor
relay tests,
REFER to: Electronic Engine Controls
(30
3-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For spark plug tests, GO to Pinpoint Test B.
.
For ign
ition system tests, GO to Pinpoint Test
A.
. F
or EGR information,
REFER to: Engine Emission Control
(30
3-08
Engine Emission Cont rol, Description and
Operation).
Engine ba
ckfires
Fue
l pump
Fue

l lines
Air leakage


Mass ai

r flow (MAF) sensor
Spark plugs


Check f

or water ingress into
spark plug wells
HT sho
rt to ground (tracking)
check rubber boots for cracks/damage
Chec
k fuel pressure,
REFER to: Fuel System Pressure Check
(31
0-
00 Fuel System - Genera l Information, General
Procedures).
For fuel pump and lines,
REFER to: Fuel Tank and Lines
(31
0-01 Fuel
Tank and Lines, Description and Operation).
For intake system,
REFER to: Intake Air Distribution and Filtering

(30
3-12 Intake Air Distribution and Filtering,
Description and Operation). For MAF sensor tests,

Driver Information
Chart
•

NOTE: Use this table to identify DTCs associated with the me
ssage center display, then refer to the DTC index for possible
sources and actions.
REF E
R to:
Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For spark plug tests, GO to Pinpoint Test B.
.
For ign i
tion system tests, GO to Pinpoint Test
A.
.
Engine s
urges
Air leakage
Fue
l
pump
Fue
l
lines
Mass ai
r fl
ow (MAF) sensor
Harness damage Throttl
e
sensors
Throttl
e
motor
Spark plugs
Check fo
r water ingress into
spark plug wells
HT short to ground (tracking) check rubber
boots for
cracks/damage
Fo r
intake system,
REFER to: Intake Air Distribution and Filtering

(30 3
-12 Intake Air Distribution and Filtering,
Description and Operation). Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
For fuel pump and lines,
REFER to: Fuel Tank and Lines
(310
-01 Fuel
Tank and Lines, Description and Operation).
For MAF sensor, throttle position sensor and
throttle motor relay tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For spark plug tests, GO to Pinpoint Test B.
.
For ign i
tion system tests, GO to Pinpoint Test
A.
.
Engine detonates/k
nocks
Fue
l
lines
F
u
el pressure regulator
Air leakage
Mass air fl
ow (MAF) sensor
O
xygen senso
rs
Fue
l
pump
F
o
r fuel lines,
REFER to: Fuel Tank and Lines
(310
-01 Fuel
Tank and Lines, Description and Operation).
For fuel pressure regulator,
REFER to: Fuel Charging and Controls
(303
-04

Fuel Charging and Controls, Diagnosis and Testing).
For intake system,
REFER to: Intake Air Distribution and Filtering

(30 3
-12 Intake Air Distribution and Filtering,
Description and Operation).
For MAF sensor and oxyg en sensor tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Check fuel pressure,
REFER to: Fuel System Pressure Check
(310
-
00 Fuel System - Genera l Information, General
Procedures).
No t
hrottle response
Throttl
e
sensors
Throttl
e
motor
Fo
r th
rottle position sensor tests, throttle
motor relay tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
Poor throttle responseThrottl e
sensors
Throttl
e
motor
Air leakage Mass air fl

ow (MAF) sensor
F
or throttl
e position se
nsor and throttle motor
relay tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).
For intake system,
REFER to: Intake Air Distribution and Filtering

(30 3
-12 Intake Air Distribution and Filtering,
Description and Operation). For MAF sensor tests,
REFER to: Electronic Engine Controls
(303
-14
Electronic Engine Co ntrols, Diagnosis and
Testing).

CAUTIO
N: When probing connectors to take
measurements in the course of the pinpoint tests, use the adaptor kit,
part number 3548-1358-00.
• NOTE: When performing electrical voltag e or resistance tests, always use a digital multimeter (DMM) accurate to 3
decimal places, and with an up-t o-date calibration certificate. When testing resistance, always take the resistance of the
DMM leads into account.
• NOTE: Check and rectify basic faults before beginning diagnostic ro utines involving pinpoint tests.
Sym
ptom Chart
Sym

ptom
(general)
S y
mptom (specific)
Possib
l
e source
Acti
o
n
No
n
-Start
Engine
does not cran
k
Starter relay ECM relay Batt
ery Park
/Neutral
switch
Starting system

Harness damage
Engine s
iezed
Check r
e
lay dates. Check
for DTCS. For starting
system,
REFER to Section 303
-06 Sta r
ting System
.
F or ECM
relay tests, GO to Pinpoint Test
AD.
.
F o
r battery information,
REFER to Section 414
-0 1
Battery, Mounting and

Cables.
Fo r

Park/Neutral tests, GO to Pinpoint Test AC.
. Fo
r engine information,
REFER to Section 303
-01 En
gine
.
Engine cranks, but does
not fireSecurity
syst
em /Immobiliser
engaged
Thr o
ttle contaminated
Harness damage
Fu
el pump relay
Fue
l
system
R
e
fer to service action
S491
Contact dealer techni
cal
support for information
on security system. For fuel system,
REFER to Section 303
-0 4
Fuel Charging and
Controls.
Check bull etins for throttl
e cleaning procedure.
Check service actions.
Engine cranks an d
fires,
but will not start
F u
el pump relay
Thr
o
ttle contaminated
Purge
val
ve
Fue
l
pump
Engine coolan
t
temperature

(ECT) sensor
Spark plugs
fouled
Ignition coil
fail
ure(s)
Check f
o
r water ingress
into spark plug wells
HT sh o
rt to ground
(tracking) check rubber
boots for cracks/damage
Cyli
nder compression loss
(short-term. Refer to bulletin; 303-52)
Re
fer to service action
S491
Fo
r fuel pump relay tests,
REFER to Section 303
-0 4
Fuel Charging and
Controls.
. Check bulletins for throttl
e cleaning procedure.

Check fuel pressure. Refe r to Technical service
bulletins. For ECT sensor tests, GO to Pinpoint Test C.
. Fo
r ignition system,
REFER to Section 303
-07 En
gine Ignition
.
Check bulletins an d service a
ctions.
Di
f
ficult to
start
D iff
icult to start cold
Roc
h
ester valve
Batt
ery Thro
ttle contaminated
Fue
l
pump
Engine coolan
t
temperature

(ECT) sensor
Purge val
ve
Cyl
i
nder compression loss
(short-term. Refer to bulletin; 303-52)
Blocked part-load breather (s
ervice action S474)
R
e
fer to service action
S491
For R
ochester valv
e test, GO to Pinpoint Test AE.
. Fo
r battery information,
REFER to Section 414
-0 1
Battery, Mounting and

Cables.
Check bull etins for throttl
e cleaning procedure.
Check fuel pressure. For ECT sensor circuit tests,
GO to Pinpoint Test C.
. F
or evaporative
emissions tests,
REFER to Section 303
-1 3
Evaporative
Emiss
i
ons
.
R e
fer to bulletins for co
mpression information,
and service actions for part-load breather procedure and compressions.
Diff
icult to start hot
Roc
h
ester valve
Purge
val
ve
Thr
o
ttle contaminated
F
or R
ochester valv
e test, GO to Pinpoint Test AE.
. F
or evaporative emissions tests,
REFER to Section 303
-1 3
Evaporative

Fue
l pump
Engine coolan

t temperature

(ECT) sensor
Blocked part-load breather (
service action S474)
Injec

tor leak
Emiss
ions
.
Check bull
etins for throttle cleaning procedure.
Check fuel pressure. For ECT sensor circuit tests,
GO to Pinpoint Test C.
. Refer to Servi
ce action
S474 for part-load breather procedure. For
injector leak test, Refer to technical service bulletin 303-39.
D
ifficult to start after hot
soak (vehicle standing
after engine has reached operating temperature)
Roc
hester valve
Thr

ottle contaminated
Purge

valve
Fue

l pump
Engine coolan

t temperature

(ECT) sensor
Blocked part-load breather (
service action S474)
Injec

tor leak
Engine cranks too
fa
st/slow
Batt
ery
Starter relay Harness Cyl

inder compression loss
(NA short term only. Refer to technical service bulletin; 303-39)
R
efer to service action
S491
F
or battery information,
REFER to Section 414
-0
1 Battery, Mounting and

Cables.
F
or starting system.
REFER to Section 303
-06 Sta
rting System
.
R
efer to technical servic
e bulletins and service
actions.
Engine

stalls
Engine st
alls soon after
start
F
uel pump relay
ECM relay Thr

ottle contaminated
CMP/CKP sen

sor
synchronization malfunction
Harness Fue
l pump
MAF

sensor malfunction
Engine coolan

t temperature

(ECT) sensor
Fue
l lines
Air leakage


F

uel pressure regulator
Check r
elay dates. Chec
k for DTCs. For fuel
pump relay tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or ECM relay tests, GO to Pinpoint Test
AD.
.
Check bull
etins for throttle cleaning procedure.
For CMP sensor circuit test s, GO to Pinpoint Test
C.
, for
CKP sensor circuit tests, GO to Pinpoint
Test N.
. Check fuel
pressure. For MAF sensor
circuit tests, GO to Pinpoint Test A.
. For EC
T
sensor tests, GO to Pinpoint Test C.
. F
or fuel
system,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
and
REF
ER to Section 310
-0
1 Fuel Tank and Lines
. F

or intake system information,
REFER to Section 303
-1
2 Intake Air Distribution

and F
iltering
.
Engine

stalls on overrun
Thr
ottle contaminated
ECM relay F

uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Check bull
etins for throttle cleaning procedure.
Check relay dates. For ECM relay tests, GO to Pinpoint Test AD.
. F
or fuel pump relay tests,

REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s, GO to Pinpoint Test
O.
, for
CKP sensor circuit tests, GO to Pinpoint
Test N.
.
E
ngine stalls at steady
speed, with or without cruise enabled
Thr
ottle contaminated
ECM relay F

uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Harness Blocked part-load breather
(
service action S474)
Check bull
etins for throttle cleaning procedure.
Check relay dates. For EC M relay circuit tests,GO
to Pinpoint Test AD.
. F
or fuel pump relay circuit

tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s,GO to Pinpoint Test
O.
, for
CKP sensor circuit tests,GO to Pinpoint
Test N.
. Che
ck service actions.
Engine st

alls when
maneuvering
ECM relay F
uel pump relay
CMP/CKP sen

sor
synchronization malfunction
Check r
elay dates. For EC
M relay circuit tests,GO
to Pinpoint Test AD.
. F
or fuel pump relay circuit

tests,
REFER to Section 303
-0
4 Fuel Charging and
Controls.
F
or CMP sensor circuit test
s,GO to Pinpoint Test
O.
, for
CKP sensor circuit tests,GO to Pinpoint
Test N.
.

P1122Acce
lerator pedal position (APP)
sensor circuit 'A' low voltage
A
PP sensor to ECM sense circuit
'A' (sensor pin 5) open circuit or
high resistance
Sensor power su
pply fault
APP s

ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1123Acce
lerator pedal position (APP)
sensor circuit 'A' high voltage
A
PP sensor to ECM sense circuit
'A' (sensor pin 5) short circuit to
high voltage
APP s
ensor failure
For APP
sensor circuit tests, GO to
Pinpoint Test R.
, and G
O to Pinpoint
Test S.
.
P1221Acce
lerator pedal position (APP)
sensor circuit 'B'
range/performance
A
PP sensor to ECM sense circuit
'B' (sensor pin 3) open circuit,
short circuit or high resistance
Sensor power su
pply fault
Sensor r

eference ground fault
APP s

ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1222Acce
lerator pedal position (APP)
sensor circuit 'B' low voltage
A
PP sensor to ECM sense circuit
'B' (sensor pin 3) open circuit or
high resistance
Sensor power su
pply fault
APP s

ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1223Acce
lerator pedal position (APP)
sensor circuit 'B' high voltage
A
PP sensor to ECM sense circuit
'B' (sensor pin 3) short circuit to
high voltage
APP s
ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1224Throttl
e control position error
Thro
ttle position adaptations not
performed after ba ttery disconnect
TP se
nsor disconnected
TP se

nsor to ECM sense circuits
open circuit, hi gh resistance
Throttl
e motor power relay failure
Throttl

e motor power relay to ECM
circuit fault
Throttl
e motor power relay power
supply open circuit
ECM ground circuit faul
t (relay coil
drive)
Th
rottle motor to ECM drive circuits

open circuit, short circuit, high
resistance
Throttl
e motor failure
Throttl

e assembly failure
Carry
out throttle adaptation
procedure. For TP sensor circuit
tests,GO to Pinpoint Test D.
, andG
O
to Pinpoint Test K.
. F
or throttle motor

circuit tests,GO to Pinpoint Test T.
.
F
or throttle body information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1226Mechanica

l guard sensor
range/performance
Mechanica
l guard sensor to ECM
sense circuit open circuit, short
circuit or high resistance
Sensor power su
pply fault
Sensor r

eference ground fault
Mechanica

l guard sensor failure
Mechanica

l guard actuator
seized/spring broken
For mech
anical guard circuit tests,GO
to Pinpoint Test U.
. F
or sensor power
supply circuit tests,GO to Pinpoint
Test V.
. F
or sensor ground circuit
tests,GO to Pinpoint Test W.
. For
throttle body i
nformation,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1227Mechanica

l guard sensor circuit
low voltage
Mechanica
l guard sensor to ECM
sense circuit open circuit or high
resistance
Sensor power su
pply fault
Mechanica

l guard sensor failure
For mech
anical guard circuit tests,GO
to Pinpoint Test U.
. F
or sensor power
supply circuit tests,GO to Pinpoint
Test V.
. F
or throttle body
information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1228Mechanica

l guard sensor circuit
high voltage
Mechanica
l guard sensor to ECM
sense circuit short circuit to high
voltage
Mechanica
l guard sensor failure
For mech
anical guard circuit tests,GO
to Pinpoint Test U.
. F
or throttle body
information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1229Throttl

e motor control circuit
mallfunction
Throttl
e motor disconnected
Th

rottle motor to ECM drive circuits

short circuit or open circuit
Throttl
e motor failure
Fo
r throttle motor circuit tests,GO to
Pinpoint Test T.
.
P1230Fue
l pump relay malfunction.
NOTE. This DTC covers the S/C
system fuel pump 1
F
uel pump relay failure
F

uel pump to ECM circuit fault
F

uel pump relay coil power supply
F
or fuel pump relay circuit tests,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.

Pinpoint Tests
f
ailure
P1611Thr

ottle angle malfunction
TP sensor
circuit fault (refer to
P0121)
APP sensor circuit faul
t (refer to
P0121)
Throttl
e assembly failure
ECM failu

re
Se
e pinpoint tests for components
listed. For throttle body information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
Contact deal
er technical support for
advice on possible ECM failure.
P1612Throttl
e offset malfunction
TP sensor
circuit fault (refer to
P0121)
APP sensor circuit faul
t (refer to
P0121)
Throttl
e assembly failure
ECM failu

re
Se
e pinpoint tests for components
listed. For throttle body information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
Contact deal
er technical support for
advice on possible ECM failure.
P1637CAN AB
S/TCCM token missing
CAN
open circuit fault - ABS/TCCM
to ECM
CAN s
hort circuit fault
ABS/TCCM failu

re
ECM failu

re
F
or network circuit tests,
REFER to Section 418
-00
Module
Comm

unications Network
.
P1638CAN INST token missingCAN

open circuit fault - INST to
ECM
CAN s
hort circuit fault
INST

failure
ECM failu

re
F
or network circuit tests,
REFER to Section 418
-00
Module
Comm

unications Network
.
P1642CAN c

ircuit malfunction
CAN s
hort circuit fault
Control modul

e failure - check for
additional logged DTCs to locate
control module source
F
or network circuit tests,
REFER to Section 418
-00
Module
Comm

unications Network
.
P1643CAN TC

M token missing
CAN
open circuit fault - TCM to
ECM
CAN s
hort circuit fault
TCM failure


ECM failu

re
F
or network circuit tests,
REFER to Section 418
-00
Module
Comm

unications Network
.
P1646F

uel pump 2 relay malfunction.
NOTE: This DTC applies only to
the S/C fuel pump 2
F
uel pump 2 relay failure
F

uel pump 2 relay to ECM circuit
fault
F
uel pump 2 relay coil power
supply open circuit
ECM ground circuit faul
t (relay coil
drive)
F
or fuel pump 2 relay circuit tests,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P

INPOINT TEST A : DTC P0101, P0102, P0103; MASS AIR FLOW (MAF) SENSOR
RANGE/PERFORMANCE, HIGH/LOW VOLTAGE
•
NOTE: Before commencing this
test, check the air filter for blockage, the engine air inta ke and breather systems for
leaks, and the TPS for additional DTCs.
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1: CHECK

THE MAF SENSOR SENS
E CIRCUIT FOR HIGH RESISTANCE
Di
sconnect the battery negative terminal.
1
D

isconnect the ECM electrical connector, EM12.
2
Di

sconnect the MAF sensor electrical connector, PI35.
3
Meas

ure the resistance between EM12, pin 13 (GY) and PI35, pin 02 (GY).
4
Is th

e resistance greater than 5 ohms?
Yes REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. CLEAR the
DTC. TEST the system for normal operation.
No GO to A2
.
A2: CHECK
THE MAF SENSOR SENSE CI
RCUIT FOR SHORT TO HIGH VOLTAGE
R
econnect the battery negative terminal.
1
Turn the ignition swi

tch to the ON
position.
2
M
easure the voltage between the MAF sensor electrical connector, PI35, pin 02 (GY) and GROUND.
3
Is th

e voltage greater than 3 volts?