relay CHEVROLET DYNASTY 1993 Service Manual

Wiring Diagram
Name Sheet Number
Right Rear Motor ...........................58
Right Rear Switch ...........................58
Printed Circuit Board ....................... .74, 75
Printed Circuit Board Connectors ...................73
Radiator Fan Fuse ......................... .45, 50
Radio Speakers-Door and Rear ....................66
Radio-Stereo ................................65
Name Brand Speaker Relay .....................65
Rear Lighting ....................... .69, 70, 71, 72
Back-Up Lamps .................... .69, 70, 71, 72
Center High Mounted Stop Lamps ..............70, 72
Courtesy Lamps ............................72
License Lamps ......................... .70, 72
Side Marker Lamps ................. .69, 70, 71, 72
Tail, Stop and Turn Signal Lamps .........69, 70, 71, 72
Relay Module ...............................77
Relays ABS System Relay ..........................28
A/C Compressor Clutch Relay ...................50
ABS Yellow Light Relay .......................28
ABS Pump Motor Relay .......................27
Automatic Shut Down ....................2,14,22
Back-Up Lamp Relay .........................23
Engine Starter Relay ....................7,8,9,10
Fuel Pump ............................ .14, 22
Horn ...................................42
Fan Control Relay ....................... .45, 50
Name Brand Speaker .........................65
Safety Shut Down Relay .......................25
Time Delay ...............................44
Right Front Wheel Sensor .......................26
Right Instrument Panel Interface ...................89
Right Rear Wheel Sensor ........................26
Seat Belt Warning System and Courtesy Lamps .......43, 44
Halo Lamp ...............................44
Seat Belt Warning Chime ......................43
Seat Belt Switch ............................44
Time Delay Relay ...........................44
Seat-Power System, Left ........................60
Sensors ABS Wheel Sensors ..........................26
A/C Ambient Temperature Sensor .................41
Airbag ..................................35
Engine Coolant Temperature ..................15, 18
Heated Oxygen ......................... .17, 18
MAP ................................ .15, 20
Output Speed Sensor .........................24
Throttle Position ........................ .16, 20
Turbine Speed .............................24
Vehicle Speed Sensor ..................... .15, 18
Washer Low Fluid Sensor ......................53
Solenoids EVAP/Purge Solenoid ..................... .13, 19
Exhaust Gas Recirculation .................. .13, 20
Transmission EMCC Solenoid ....................8
Transmission Solenoid ........................25
Speakers, Radio ..............................66Wiring Diagram
Name Sheet Number
Splices Splice A0-1 ...........................1,2,4,6
Splice A0-2 ............................2,4,6
Splice A1 ..............................2,4,6
Splice A2 ..............................2,4,6
Splice A3 ..............................1,36
Splice A3-1 ............................1,4,6
Splice A4 ..............................2,3,5
Splice A4-1 ............................2,4,6
Splice A11 .............................1,4,6
Splice A14 .............................2,4,6
Splice A14-1 ..............................14
Splice A14-2 ..............................22
Splice A15 .............................1,3,5
Splice A15-1 ...........................1,3,5
Splice A16 .............................2,4,6
Splice A20 ...............................28
Splice A21 ...............................11
Splice A21-1 ..........................2,13,21
Splice A21-2 ........................... .13, 21
Splice A21-3 ..............................23
Splice A142-1 .............................14
Splice A142-2 ..........................4,6,14
Splice B47 ...............................28
Splice C7 ............................. .46, 48
Splice D1 ................................24
Splice D2 ................................24
Splice E2 .............. .31, 33, 37, 41, 46, 47, 65, 67
Splice E2-1 ............ .31, 33, 37, 41, 46, 47, 65, 67
Splice F20 .......................... .35, 41, 67
Splice F20-1 .........................7,8,9,23
Splice F30 .......................... .35, 42, 65
Splice F35 ............................ .61, 63
Splice G5 ............................. .35, 43
Splice G7 .......................... .15, 18, 30
Splice K4 ................................15
Splice K4-1 ........................... .15, 18
Splice K4-2 ........................... .19, 20
Splice K6 ............................. .16, 20
Splice K7-1 ........................... .15, 18
Splice K22 ...............................20
Splice K24 ...............................18
Splice L3 ............................. .31, 33
Splice L4 ............................. .31, 33
Splice L7-1 ........................... .32, 34
Splice L7-2 ........................... .31, 33
Splice L7-3 ...............................36
Splice L7-4 ........................... .69, 71
Splice L7-5 ........................... .31, 33
Splice L20 ..............................1,36
Splice L39 ............................ .31, 33
Splice L50 ...............................52
Splice L60 ............................ .31, 33
Splice L60-1 ..............................52
Splice L61 ............................ .32, 34
Splice L61-1 ..............................52
Splice M1-1 ...................... .39, 44, 55, 65
8W - 720 WIRING DIAGRAMS AP BODY D-P Ä

Wiring Diagram
Name Sheet Number
Splice M1-3 ........................... .40, 55
Splice M2-1 ...............................39
Splice P33 ............................ .62, 64
Splice P34 ............................ .62, 64
Splice Q1 ................................58
Splice T13 ...............................24
Splice T16 ...............................25
Splice T41 ...............................23
Splice T41-1 ............................9,10
Splice X2 ................................42
Splice X2-1 ...............................42
Splice X13 ...............................66
Splice X15 ...............................66
Splice Z0 .................................3
Splice Z0-1 ...............................14
Splice Z0-2 ...............................21
Splice Z1 ......... .40, 44, 55, 57, 60, 61, 63, 68, 69, 71
Splice Z1-1 ...................... .38, 46, 47, 66
Splice Z1-2 ......................... .31, 33, 42
Splice Z1-3 ......................... .32, 34, 42
Splice Z1-4 ............7,27,28,29,32,34,42,45,49
Splice Z1-5 .................... .55, 57, 60, 61, 63
Splice Z1-6 ...............................38
Splice Z1-7 ........................... .70, 72
Splice Z1-8 ........................... .67, 70
Splice Z1-10 ........................... .32, 34
Splice Z1-11 ........................ .32, 34, 42
Splice Z1-12 .............. .55, 57, 60, 61, 63, 69, 71
Splice Z1-14 ........................... .27, 28
Splice Z2 ................................38
Splice Z12 ............................ .14, 21
Splice Z13 ...............................25
Splice Z14 ...............................25
Steering Column Connectors ......................81
Steering Multi-Function Switch Column Connectors .......82
Stereo Radio ................................65
Stop Lamp System ............................29
Stop Lamp Switch ............................29
Switches A/C Cycling Clutch Switch ......................48
A/C Switch ...............................47
A/C Heater Blower Switch ......................47
A/C High Pressure Switch ......................48
A/C Low Pressure Switch ......................48
Back-Up Lamp Switch .....................7,8,9
Blower Switch-A/C Heater ......................47
Brake Warning Lamp Switch ....................11
Clutch Pedal Position Switch ...................7,9
Defrost Switch .............................47
Door Lock Switch (2-dr) ................... .61, 62
Door Lock Switch (4-dr) ................... .63, 64
Door Jamb Switch ....................... .39, 40
Dual Mirror Control Switch .....................55
Engine Oil Pressure Switch .....................12
Fog Lamp Switch ........................ .31, 33
Glove Box Lamp Switch .......................39
Hazard Flasher Switch ........................52Wiring Diagram
Name Sheet Number
Headlamp Switch .........................1,36
Heated Rear Window Switch ....................67
Heater Bi-level Control Switch ...................46
Horn Switch ..............................42
Ignition Switch ...........................2,11
Liftgate Latch Switch .........................40
Mercury Switch ............................12
Park Brake Switch ...........................11
Park/Neutral Position Switch .....................8
Park/Neutral Start Switch ......................23
Power Mirrors Switch ........................55
Power Seat Switch ..........................60
Power Steering Pressure Switch ..................19
Power Window Switch (2 Dr) ...................57
Power Window Switch (4 Dr) ...................58
Seat Belt Warning Switch ......................44
Speed Control Switch ........................29
Stop Lamp Switch ..........................29
Transmission Range Switch .....................25
Transmission Solenoids and Pressure Switch ..........25
Turn Signal Flasher Switch .....................52
Vehicle Speed Control Switch ...................29
Wiper Park Switch ..........................54
Wiper Switch ..............................53
Temperature Sending Unit .......................18
Time Delay Relay .............................44
Throttle Position (Sensor) 2.2L ....................16
Throttle Position (Sensor) 2.5L ....................16
THrottle Position (Sensor) 3.0L ....................20
Transmission Control Module Connector ..............91
Transmission Control System ................23, 24, 25
Back-up Lamp Relay .........................23
Output Speed Sensor .........................24
Park/Neutral Switch ..........................23
Safety Shut Down Relay .......................25
Transmission Control Module ...............23, 24, 25
Transmission Range Switch .....................25
Transmission Solenoids and Pressure Switch ..........25
Turbine Speed Sensor ........................24
Transmission EMCC Solenoid ......................8
Transmission Solenoid Connector ..................92
Transmission Solenoids and Pressure Switch ...........25
Turn and Hazard Flasher System .................51, 52
Hazard Flasher ......................... .51, 52
Switch ..................................52
Turn Signal Flasher ..........................51
Turn Signal Lamps ..........31, 32, 33, 34, 69, 70, 71, 72
Underhood Lamp .............................12
Vehicle Speed Control Servo ......................29
Vehicle Speed Control and Stop Lamp System ..........29
Clockspring ................................29
Powertrain Control Module .......................29
Stop Lamp Switch with Vehicle Speed Control ..........29
Stop Lamp without Vehicle Speed Control .............29
Vehicle Speed Control Servo ......................29
Vehicle Speed Control Switch .....................29
Wiper System ........................... .53, 54
Ä WIRING DIAGRAMS AP BODY D-P 8W - 721

CLEANING AND INSPECTION
(1) Discard gaskets and clean all gasket surfaces
on both manifolds and on cylinder head. (2) Test gasket surfaces of manifolds for flatness
with a straight edge. Surfaces must be flat within
0.15mm per 300mm (.006 in. per foot) of manifold
length. (3) Inspect manifolds for cracks and distortion.
INSTALLATION
(1) Install a new intake and exhaust manifold gas-
ket. Coat steel gasket lightly with Gasket Sealer on
manifold side. Do notcoat composition gasket with
(any) sealer. (2) Set exhaust manifold in place. Tighten retain-
ing nuts starting at center and progressing outward
in both directions to 23 N Im (200 in. lbs.) torque. Re-
peat this procedure until all nuts are at specified
torque. (3) Set intake manifold in place.
(4) Raise vehicle and tighten retaining screws
starting at center and progressing outward in both
directions to 23 N Im (200 in. lbs.) torque (Fig. 3). Re-
peat this procedure until all screws are at specified
torque. (5) Reverse removal procedures 1-9 for installation.
(6) With the DRBII Scan Tool use ASD Fuel Sys-
tem Test to pressurize system to check for leaks.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is se-
lected.
INTAKE AND EXHAUST MANIFOLDSÐFLEXIBLE
FUEL ENGINE
INTAKE MANIFOLD
The manifold is die-cast aluminum with upper ple-
num and 4 tubes lower runners. These attach to the
cylinder head, with each runner leading directly to a
cylinder. The manifold is also machined for fuel rail attach-
ment and injector installation. The throttle body is
installed on the upper plenum of the manifold.
EXHAUST MANIFOLD
All high strength iron casting that intermesh with
the intake manifold. For standard engines a four
branch design collects and directs exhaust gases to
the conical (articulated joint connection) outlet.
INTAKE/EXHAUST MANIFOLDS
SERVICEÐFLEXIBLE FUEL ENGINES
Intake and exhaust manifolds use a one piece gas-
ket. Service procedures requiring removal and instal-
lation of either must include both manifolds.
SERVICE PRECAUTIONS
Methanol is more toxic than gasoline. Always re-
lease fuel system pressure before servicing fuel sys-
tem components and wear methanol resistant gloves
and eye protection. Avoid breathing methanol vapors or ingesting
methanol. Headaches, dizziness and even uncon-
sciousness could result from breathing these vapors.
Serious injury, blindness and even death could result
from ingesting methanol. Methanol vapors are extremely flammable and can
travel along the ground. Service vehicles in well ven-
tilated areas and avoid ignition sources. Never
smoke while servicing the vehicle. Do not allow methanol to contact skin. Prolonged
contact with methanol can cause dry skin or an al-
lergic skin reaction. Also, prolonged contact could re-
sult in absorption through the skin.
FUEL SYSTEM PRESSURE RELEASE PROCEDURE
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
WEAR METHANOL RESISTANT GLOVES AND EYE
PROTECTION WHILE SERVICING THE FUEL SYS-
TEM.
(a) Disconnect negative cable from battery.
(b) Remove fuel filler cap.
(c) Remove the protective cap from the fuel pres-
sure test port on the fuel rail (Fig. 4).
(d) Place the open end of fuel pressure release
hose, tool number C-4799-1, into an approved gas-
oline container. Connect the other end of hose
C-4799-1 to the fuel pressure test port (Fig. 5).
Fuel pressure will bleed off through the hose into
the gasoline container. Fuel gauge C-4799-A con-
tains hose C-4799-1.
Fig. 4 Fuel Pressure Test Port
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 7

EXHAUST MANIFOLD
REMOVAL (1) Disconnect exhaust pipe from manifold articu-
late joint. (2) Disconnect the heated oxygen sensor electrical
connection. (3) Remove 8 exhaust manifold retaining nuts and
remove exhaust manifold (Fig. 9).
CLEANING AND INSPECTION
(1) Discard gasket and clean all gasket surfaces of
manifolds and cylinder head. (2) Test gasket surfaces for flatness with straight
edge. Surface must be flat within 0.15 mm per 300
mm (.006 in. per foot) of manifold length. (3) Inspect manifolds for cracks or distortion.
EXHAUST MANIFOLD
INSTALLATION
(1) Install new two-sided grafoil or equivalent in-
take/exhaust manifold gasket. DO NOT APPLY
SEALER. (2) Set exhaust manifold in place. Install and
tighten retaining nuts, starting at center and pro-
gressing outward in both directions to 23 N Im (200
in. lbs.) torque. Repeat this procedure until all nuts
are at specified torque.
INTAKE MANIFOLD
INSTALLATION
(1) Position intake manifold, install, and tighten 8
retaining screws starting at center and progressing
outward in both directions to 23 N Im (200 in. lbs.)
torque. Repeat this procedure until all screws are at
specified torque (Fig. 9). (2) Install PCV vacuum harness and vacuum vapor
harness (Fig. 8). (3) Connect vacuum hose from fuel pressure regu-
lator. (4) Connect fuel injector wiring connector (Fig. 8).
(5) Close fuel tube clip around fuel tubes and in-
stall fastener. (6) Lubricate the ends of the chassis fuel tubes
with 30 wt oil. Connect fuel supply and return hoses
to chassis fuel tube assembly. pull back on the quick
connect fitting to ensure complete insertion. (Refer to
Fuel Hoses, Clamps and Quick Connect Fittings in
Group 14 Fuel Systems). (7) Connect automatic idle speed (AIS) motor and
throttle position sensor (TPS) wiring connectors (Fig.
7). (8) Connect accelerator and speed control cables.
Install brake booster vacuum supply hoses. (9) Reconnect negative battery cable.
(10) Install air cleaner hose to throttle body assem-
bly (Fig. 6). (11) With the DRBII Scan Tool use ASD Fuel Sys-
tem Test to pressurize system to check for leaks.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is se-
lected.
INTAKE/EXHAUST MANIFOLDS AND
TURBOCHARGER SERVICEÐTURBO III ENGINE
INTAKE MANIFOLD
REMOVAL
(1) Perform fuel system pressure release procedure
before attempting any repairs. (2) Disconnect negative battery cable. Drain cool-
ing system. Refer to Cooling System, Group 7. (3) Remove fresh air duct from air filter housing.
Remove inlet hose from the intercooler (Fig. 1). (4) Remove radiator hose to cylinder head (Fig. 2).
(5) Remove DIS Ignition Coils from intake mani-
fold (Fig. 3). (6) Remove accelerator and speed control cables
(Fig. 4).
Fig. 9 Intake and Exhaust Manifolds Attaching Points
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 9

CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is se-
lected.
TURBOCHARGER
REMOVAL
The turbocharger is removed from below the vehi-
cle. Cylinder head removal for component accessibil-
ity is not required. (1) Disconnect negative battery cable. Remove Air
Cleaner assembly (Fig. 1). (2) From Above: Remove front engine mount
through bolt and rotate engine (Top) forward away
from cowl. Refer to Engine Removal in Engine,
Group 9. (3) Remove Air Cleaner Support (Fig. 1).
(4) Disconnect Heated Oxygen sensor lead wire
and vacuum lines. (5) Separate coolant return line from water box
and turbocharger housing (Fig. 11). Remove return
line from turbocharger.
(6) Separate oil feed line from turbocharger hous-
ing (Fig. 12). (7) Remove three (two upper and one lower driver's
side) nuts retaining turbocharger to manifold (Fig.
12). (8) From Below: Remove right front wheel and
tire assembly. (9) See Suspension, Group 2, and remove right
driveshaft assembly. Air deflector may need to be removed from cross-
member. (10) Separate oil drain back tube fitting from tur-
bocharger housing and remove fitting and hose (Fig.
13). (11) Remove turbocharger to block support bracket
(Fig. 13). (12) Remove one remaining turbocharger to mani-
fold retaining nut (Fig. 12).
Fig. 11 Coolant Tube Routing
Fig. 12 Turbocharger Attaching Nuts
Fig. 9 Fuel Supply and Return Hose Connections
Fig. 10 Intake Manifold Attaching Bolts.
11 - 12 EXHAUST SYSTEM AND INTAKE MANIFOLD Ä

CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is se-
lected.
Fig. 13 Check Intake (Cross) Manifold Mounting Surface
Fig. 14 Check Intake Plenum Mounting Surfaces
Fig. 10 Vacuum Connections for Fuel Rail and FuelPressure Regulator
Fig. 11 Fuel Injector Wiring Harness
Fig. 12 Fuel Pressure Regulator to Fuel Rail Assembly
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 17

(7) Put the tip of each injector into their ports.
Push the assembly into place until the injectors are
seated in the ports (Fig. 12). (8) Install the (4) fuel rail attaching bolts and
tighten to 22 N Im (200 in. lbs.) torque (Fig. 10).
(9) Install fuel tube retaining bracket screw and
tighten to 4 N Im (35 in. lbs.) torque (Fig. 10).
(10) Reconnect cam sensor, coolant temperature
sensor and engine temperature sensors (Fig. 11). (11) Install fuel injector harness wiring clips on
the generator bracket and intake manifold water
tube (Fig. 11). (12) Connect fuel pressure regulator vacuum line.
(13) Remove covering on lower intake manifold
and clean surface. (14) Place intake manifold gasket on lower mani-
fold. Put upper manifold into place and install bolts
finger tight. (15) Install the generator bracket to intake mani-
fold bolt and the cylinder head to intake manifold
strut bolts. Do not torque.
(16) Tighten intake manifold bolts to 28 N Im (250
in. lbs.) torque in the sequence shown in (Fig. 9). (17) Tighten generator bracket to intake manifold
bolt to 54 N Im (40 ft. lbs.) torque (Fig. 8).
(18) Tighten the cylinder head to intake manifold
strut bolts to 54 N Im (40 ft. lbs.) torque (Fig. 5).
(19) Connect ground strap, MAP and heated oxy-
gen sensor electrical connectors (Fig. 6). (20) Connect charge temperature sensor electrical
connector (Fig. 5). (21) Connect vacuum harness to intake plenum
(Fig. 5). (22) Using a new gasket, connect the EGR tube
flange to the intake manifold and tighten to 22 N Im
(200 in. lbs.) torque. (23) Clip wiring harness into the hole in the throt-
tle cable bracket. (24) Connect the wiring connectors to the throttle
position sensor TPS and automatic idle speed AIS
motor (Fig. 4). (25) Connect vacuum harness to throttle body (Fig.
4). (26) Install the direct ignition system DIS coils.
Tighten fasteners to 12 N Im (105 in. lbs.) torque
(Fig. 8). (27) Lubricate the ends of the chassis fuel tubes
with 30 wt oil. Connect fuel supply and return hoses
to chassis fuel tube assembly. pull back on the quick
connect fitting to ensure complete insertion (Fig. 7).
(Refer to Fuel Hoses, Clamps and Quick Connect Fit-
tings in Group 14 Fuel Systems). (28) Install throttle cable (Fig. 3).
(29) Connect fuel injector wiring harness.
(30) Install air cleaner and hose assembly (Fig. 2).
(31) Connect negative battery cable. Fill Cooling
System. See Cooling System, Group 7. (32) With the DRBII Scan Tool use ASD Fuel Sys-
tem Test to pressurize system to check for leaks.
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) relay will remain ener-
gized for 7 minutes or until the ignition switch is
turned to the OFF position, or Stop All Test is se-
lected.
EXHAUST MANIFOLDS
REMOVAL
(1) Raise vehicle and disconnect exhaust pipe from
rear cowl side exhaust manifold at articulated joint. (2) Separate EGR tube from rear manifold and dis-
connect Heated Oxygen Sensor lead wire (Fig. 16). (3) Remove Generator/Power Steering Support
Strut (Fig. 16). (4) Remove bolts attaching cross-over pipe to man-
ifold (Fig. 16).
Fig. 15 Intake Manifold Gasket Sealing
Fig. 16 EGR Tube, Heated Oxygen Sensor and Generator/Power Steering Strut
Ä EXHAUST SYSTEM AND INTAKE MANIFOLD 11 - 23

(1) Loosen fuel filler cap to release fuel tank pres-
sure. (2) Disconnect injector wiring harness connector at
edge of throttle body (Fig. 4). (3) Connect a jumper wire between terminal Num-
ber 1 of the injector harness and engine ground. (4) Connect a jumper wire to the positive terminal
Number 2 of the injector harness and touch the bat-
tery positive post for no longer than 5 seconds .
This releases system pressure. (5) Remove jumper wires.
(6) Continue fuel system service.
FUEL SYSTEM PRESSURE RELEASE
PROCEDUREÐ3.0L
(1) Disconnect the fuel rail electrical harness from
the engine harness. Refer to Group 8W, Wiring Dia-
grams. (2) Connect one end of a jumper wire to the A142
circuit terminal of the fuel rail harness connector. (3) Connect the other end of the jumper wire to a
12 volt power source. (4) Connect one end of a jumper wire to a good
ground source. (5) Momentarily ground one of the injectors by
connecting the other end of the jumper wire to an in-
jector terminal in the harness connector. Repeat pro-
cedure for 2 to 3 injectors.
FUEL PUMP ASSEMBLY
The fuel pump assembly consists of the fuel pump
and the reservoir body. The reservoir body takes the place of an internal
fuel tank reservoir. The reservoir maintains fuel at
the pump inlet during all driving conditions, espe-
cially when the fuel level is low. The system uses a positive displacement, gerotor
gear, immersible pump with a permanent magnet
electric motor (Fig. 5). The pump draws fuel through
a strainer and pushes it through the electric motor to
the outlet. The pump contains three check valves.
One valve relieves internal fuel pump pressure and
regulates maximum pump output. Another valve, in-
side the pump assembly in the fuel return circuit,
prevents fuel tank leakage if the line is damaged
during an accident. The third valve, in the pump out-
let, maintains pump pressure during engine off con-
ditions. The fuel pump relay provides voltage to the
fuel pump. All pumps have a maximum stall pres-
sure output of approximately 930 kPa (135 psi). All front wheel drive car fuel systems, except
Turbo III and flexible fuel AA-body vehicles use the
same fuel pump. Turbo III and flexible fuel AA-Body
vehicles each use different fuel pumps although they
look similar to pumps used in other vehicles. Release fuel system pressure before servicing the
fuel tank, fuel pump, fuel lines, fuel filter, or parts of
the fuel rail. Follow the Fuel System Pressure Re-
lease procedure to relieve fuel system pressure.
Fig. 2 Fuel Pressure Test PortÐTypical
Fig. 3 Releasing Fuel PressureÐEngines With Test Ports On Fuel Rail
Fig. 4 Injector Harness ConnectorÐ2.2L/2.5L TBI
Ä FUEL SYSTEMS 14 - 5

FUEL SYSTEM PRESSURE
Fuel system pressure is regulated at the fuel rail
or throttle body by a fuel pressure regulator. Refer to
the Fuel System Pressure Chart for pressure specifi-
cations. The chart reflects system pressure when the
pump is energized with the engine not running and
without vacuum applied to the pressure regulator.
FUEL PUMP PRESSURE TESTÐALL EXCEPT
2.2L/2.5L TBI AND 3.0L MPI
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
WHEN SERVICING FLEXIBLE FUEL VEHICLES,
WEAR METHANOL RESISTANT GLOVES AND EYE
PROTECTION AND AVOID BREATHING FUMES. DO
NOT ALLOW METHANOL/GASOLINE MIXTURES TO
CONTACT SKIN. SERVICE VEHICLES IN WELL VEN-
TILATED AREAS AND AVOID IGNITION SOURCES.
NEVER SMOKE WHILE SERVICING THE VEHICLE.
The specifications in the Fuel Pressure chart re-
flect system pressure with the vacuum hose removed
from the pressure regulator. (1) Remove the vacuum hose from the pressure
regulator before checking fuel pressure. (2) Release fuel system pressure. Refer to the Fuel
System Pressure Release procedure in this section. (3) Connect Fuel Pressure Gauge C-4799 to service
port on fuel rail (Fig. 6).
CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) Relay remains energized
for either 7 minutes, until the test is stopped, or un-
til the ignition switch is turned to the Off position.
(4) Place the ignition key in the ON position. Us-
ing the DRBII scan tool, access ASD Fuel System
Test. The ASD Fuel System Test will activate the
fuel pump and pressurize the system. If the gauge reads the specification listed in the
Fuel System Pressure chart, further testing is not re-
quired. If pressure is not correct, record the pressure
and remove gauge. Use the DRBII scan tool ASD
Fuel System Test to pressurize the system. Ensure
fuel does not leak from the fuel rail service valve. In-
stall protective cover on fuel rail service valve. If pressure is below specifications, proceed to Fuel
System Pressure Below Specifications . If pres-
sure is above specifications, proceed to Fuel System
Pressure Above Specifications .
Fuel System Pressure Below Specifications
If the fuel pressure reading in step (4) was below
specifications, test the system according to the fol-
lowing procedure.
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE DISCONNECTING A FUEL SYSTEM HOSE
OR COMPONENT.
(a) Perform Fuel Pressure Release procedure.
(b) Install Fuel Pressure Gauge C-4799 and Fuel
Pressure Test Adapter 6539 in the fuel supply line
between the fuel tank and fuel filter at the rear of
vehicle (Fig. 7). (c) Using the DRBII scan tool, with the ignition
key in the ON position, repeat the ASD Fuel Sys-
tem Test.
Fig. 5 Fuel PumpÐTypical
FUEL SYSTEM PRESSURE
Fig. 6 Fuel Pressure TestingÐEngines With Service Ports
14 - 6 FUEL SYSTEMS Ä

CAUTION: When using the ASD Fuel System Test,
the Auto Shutdown (ASD) Relay remains energized
for either 7 minutes, until the test is stopped, or un-
til the ignition switch is turned to the Off position.
(4) Place the ignition key in the ON position. Us-
ing the DRBII scan tool, access ASD Fuel System
Test. The ASD Fuel System Test will activate the
fuel pump and pressurize the system. If the gauge reads the pressure shown in the Fuel
System Pressure chart, further testing is not re-
quired. If pressure is not correct, record the pressure
and remove gauge. If pressure is below specifications, proceed to Fuel
System Pressure Below Specifications . If pressure
is above specifications, proceed to Fuel System
Pressure Above Specifications .
Fuel System Pressure Below Specifications
If the fuel pressure reading in step (4) was below
specifications, test the system according to the fol-
lowing procedure.
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE DISCONNECTING A FUEL SYSTEM HOSE
OR COMPONENT.
(a) Perform Fuel Pressure Release procedure.
(b) Install Fuel Pressure Gauge C-4799 and Fuel
Pressure Adapter 6433 in the fuel supply line (Fig.
7) between the fuel tank and fuel filter. (c) Using the DRBII scan tool, with the ignition
key in the ON position, repeat the ASD Fuel Sys-
tem Test.
² If pressure is at least 5 psi higher than reading
recorded in step (4), replace fuel filter. ² If no change is observed, gently the squeeze re-
turn hose. If fuel pressure increases, replace pressure
regulator. If the gauge reading does not change while
squeezing the return hose, the problem is either a
plugged inlet strainer or defective fuel pump. Fuel System Pressure Above Specifications If the fuel pressure reading in step (4) was above
specifications test the system according to the follow-
ing procedure.
WARNING: FUEL SYSTEM PRESSURE MUST BE
RELEASED BEFORE A FUEL SYSTEM HOSE OR
COMPONENT IS DISCONNECTED.
(a) Perform Fuel Pressure Release procedure.
(b) Install Fuel Pressure Gauge C-4799 and Fuel
Pressure Adapter 6433 in the fuel supply line be-
tween the fuel tank and fuel filter (Fig. 7). (c) Remove the fuel return line hose from the
fuel pump at fuel tank. Connect Fuel Pressure Test
Adapter 6541 to the return line (Fig. 8). Place the
other end of adapter 6541 into an approved gaso-
line container or a container approved for gasoline/
methanol mixtures (minimum 2 gallon size). All
return fuel will flow into container. (d) Using the DRBII scan tool, with the ignition
key in the ON position, repeat the ASD Fuel Sys-
tem Test.
² If pressure is now correct, replace fuel pump as-
sembly. ²
If pressure is still above specifications, remove fuel
return hose from chassis fuel tubes (at engine). Attach
Fuel Pressure Test Connect Adapter 6541 to the fuel re-
turn hose and place other end of hose in clean approved
gasoline container or a container approved for metha-
nol/gasoline mixtures (Fig. 9). Repeat test. If pressure is
now correct, check for restricted fuel return line. If no
change is observed, replace fuel pressure regulator.
MECHANICAL MALFUNCTIONS
Mechanical malfunctions are more difficult to diag-
nose with this system. The powertrain control mod-
ule (PCM) compensates for some mechanical
malfunctions. If engine performance problems are en-
countered, and no fault codes are displayed, the prob-
lem may be mechanical rather than electronic.
FUEL PUMP MODULE REMOVAL
WARNING: RELEASE FUEL SYSTEM PRESSURE
BEFORE SERVICING FUEL SYSTEM COMPONENTS.
WHEN SERVICING FLEXIBLE FUEL VEHICLES,
WEAR METHANOL RESISTANT GLOVES AND EYE
PROTECTION AND AVOID BREATHING FUMES. DO
NOT ALLOW METHANOL/GASOLINE MIXTURES TO
CONTACT SKIN. SERVICE VEHICLES IN WELL VEN-
TILATED AREAS AND AVOID IGNITION SOURCES.
NEVER SMOKE WHILE SERVICING THE VEHICLE.
Remove the fuel tank to service the fuel pump. Re-
fer to Fuel Tank Section for fuel tank removal. (1) Using a hammer and a brass drift punch care-
fully tap lock ring counter clockwise to release pump
(Fig. 11).
Fig. 10 Fuel Pressure Gauge and Adapter
14 - 8 FUEL SYSTEMS Ä