
6C–10
ENGINE FUEL
Reuse of Quick–Connector
(Delivery Pipe)
Replace the pipe and connector if scratch, dent or
crack is found.
Remove mud and dust from the pipe and make sure
that the end including spool is free of defects, such as
scratch, rust, and dent, which may cause poor
sealability. If defective, replace with a new pipe.
If the retainer removed according to the removal step
above is attached to the pipe, clean and insert it
straight into the quick-connector till it clicks. After it
clicks, try pulling it out to make sure that it is not drawn
and is securely locked.
NOTE: The retainer, once removed from the pipe, cannot
be reused. Just replace with a new retainer. Insert the
new retainer into the connector side until it clicks, and
connect the pipe as inserting it into the retainer until it
clicks.
141RW018
(Return Pipe)
Replace the pipe and connector if scratch, dent or
crack is found.
Remove mud or dust from the pipe and make sure
that the end including spool is free from defects, such
as scratch, rust, and dent, which may cause poor
sealability. If defective, replace with a new pipe.
After cleaning the pipe, insert it straight into the
connector until it clicks. After it clicks, try pulling it out
to make sure that it is not drawn and is securely
locked.
141RW017
Assembling Advice
Application of engine oil or light oil to the pipe facilitates
connecting work. The work should be started immediately
after lubrication, since dust may stick to the pipe surface
to cause poor sealability if a long time passes after
lubrication.
Test/Inspection After Assembling
1. Reconnect the battery negative cable.
2. Turn the ignition key to the “ON” position and check
pump startup sound. As the pump is actuated to raise
fuel pressure, check and see fuel leak from the piping
system.
3. Make sure of no fuel leakage by conducting the above
fuel leak check a few times.
4. Start the engine and make sure of stable idling speed
and normal vehicle run.The entry of dust during the
work may sometimes affect the fuel injection system.

6E–4
ENGINE DRIVEABILITY AND EMISSIONS
Knock Sensor 6E–337. . . . . . . . . . . . . . . . . . . . . . . . .
Linear Exhaust Gas Recirculation (EGR)
Control 6E–337. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mass Air Flow (MAF) Sensor 6E–337. . . . . . . . . . . .
Manifold Absolute Pressure (MAP) Sensor 6E–338
Powertrain Control Module (PCM) 6E–338. . . . . . .
PCM Function 6E–338. . . . . . . . . . . . . . . . . . . . . . . . .
PCM Components 6E–339. . . . . . . . . . . . . . . . . . . . .
PCM Voltage Description 6E–339. . . . . . . . . . . . . . .
PCM Input/Outputs 6E–339. . . . . . . . . . . . . . . . . . . .
PCM Service Precautions 6E–339. . . . . . . . . . . . . .
Reprogramming The PCM 6E–339. . . . . . . . . . . . . .
Throttle Position (TP) Sensor 6E–339. . . . . . . . . . .
Transmission Fluid Temperature (TFT)
Sensor 6E–340. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transmission Range Switch 6E–340. . . . . . . . . . . . .
Vehicle Speed Sensor (VSS) 6E–340. . . . . . . . . . . .
Use of Circuit Testing Tools 6E–340. . . . . . . . . . . . .
Aftermarket Electrical and Vacuum
Equipment 6E–340. . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrostatic Discharge Damage 6E–341. . . . . . . . .
Upshift Lamp 6E–341. . . . . . . . . . . . . . . . . . . . . . . . .
General Description (Air Induction) 6E–341. . . . . . . .
Air Induction System 6E–341. . . . . . . . . . . . . . . . . . .
General Description (Fuel Metering) 6E–341. . . . . . .
Acceleration Mode 6E–341. . . . . . . . . . . . . . . . . . . . .
Accelerator Controls 6E–341. . . . . . . . . . . . . . . . . . .
Battery Voltage Correction Mode 6E–341. . . . . . . .
CMP Signal 6E–341. . . . . . . . . . . . . . . . . . . . . . . . . . .
Clear Flood Mode 6E–342. . . . . . . . . . . . . . . . . . . . .
Deceleration Mode 6E–342. . . . . . . . . . . . . . . . . . . .
Engine Speed/Vehicle Speed/Fuel
Disable Mode 6E–342. . . . . . . . . . . . . . . . . . . . . . . .
Fuel Cutoff Mode 6E–342. . . . . . . . . . . . . . . . . . . . . .
Fuel Injector 6E–342. . . . . . . . . . . . . . . . . . . . . . . . . .
Fuel Metering System Components 6E–342. . . . . . Fuel Metering System Purpose 6E–342. . . . . . . . . .
Fuel Pressure Regulator 6E–343. . . . . . . . . . . . . . . .
Fuel Pump Electrical Circuit 6E–343. . . . . . . . . . . . .
Fuel Rail 6E–343. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Idle Air Control (IAC) Valve 6E–343. . . . . . . . . . . . .
Run Mode 6E–344. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Mode 6E–344. . . . . . . . . . . . . . . . . . . . . . . . .
Throttle Body Unit 6E–344. . . . . . . . . . . . . . . . . . . . .
General Description (Electronic Ignition
System) 6E–344. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Camshaft Position (CMP) Sensor 6E–344. . . . . . . .
Crankshaft Position (CKP) Sensor 6E–345. . . . . . .
Electronic Ignition 6E–345. . . . . . . . . . . . . . . . . . . . .
Ignition Coils 6E–345. . . . . . . . . . . . . . . . . . . . . . . . . .
Ignition Control 6E–345. . . . . . . . . . . . . . . . . . . . . . . .
Ignition Control PCM Output 6E–347. . . . . . . . . . . .
Knock Sensor (KS) PCM Input 6E–347
. . . . . . . . . .
Powertrain Control Module (PCM) 6E–347. . . . . . .
Spark Plug 6E–347. . . . . . . . . . . . . . . . . . . . . . . . . . . .
A/C Clutch Diagnosis 6E–349. . . . . . . . . . . . . . . . . . . .
A/C Clutch Circuit Operation 6E–349. . . . . . . . . . . .
A/C Clutch Circuit Purpose 6E–349. . . . . . . . . . . . .
A/C Request Signal 6E–349. . . . . . . . . . . . . . . . . . . .
General Description (Exhaust Gas
Recirculation (EGR) System) 6E–349. . . . . . . . . . . . .
EGR Purpose 6E–349. . . . . . . . . . . . . . . . . . . . . . . . .
Linear EGR Valve 6E–349. . . . . . . . . . . . . . . . . . . . .
Linear EGR Control 6E–349. . . . . . . . . . . . . . . . . . . .
Linear EGR Valve Operation and Results
of Incorrect Operation 6E–349. . . . . . . . . . . . . . . . .
EGR Pintle Position Sensor 6E–350. . . . . . . . . . . . .
General Description (Positive Crankcase
Ventilation (PCV) System) 6E–350. . . . . . . . . . . . . . .
Crankcase Ventilation System Purpose 6E–350. . .
Crankcase Ventilation System Operation 6E–350.

6E–60
ENGINE DRIVEABILITY AND EMISSIONS
Electronic Ignition System Diagnosis
If the engine cranks but will not run or immediately stalls,
the Engine Cranks But Will Not Start chart must be used
to determine if the failure is the ignition system or the fuel
system. If DTC P0341, or P0336 is set, the appropriate
diagnostic trouble code chart must be used for diagnosis.
If a misfire is being experienced with no DTC set, refer to
the
Symptoms section for diagnosis.
Fuel Metering System Check
Some failures of the fuel metering system will result in an
“Engine Cranks But Will Not Run” symptom. If this
condition exists, refer to the
Cranks But Will Not Run
chart. This chart will determine if the problem is caused
by the ignition system, the PCM, or the fuel pump
electrical circuit.
Refer to
Fuel System Electrical Test for the fuel system
wiring schematic.
If there is a fuel delivery problem, refer to
Fuel System
Diagnosis
, which diagnoses the fuel injectors, the fuel
pressure regulator, and the fuel pump. If a malfunction
occurs in the fuel metering system, it usually results in
either a rich HO2S signal or a lean HO2S signal. This
condition is indicated by the HO2S voltage, which causes
the PCM to change the fuel calculation (fuel injector pulse
width) based on the HO2S reading. Changes made to the
fuel calculation will be indicated by a change in the long
term fuel trim values which can be monitored with a Tech
2. Ideal long term fuel trim values are around 0%; for a
lean HO2S signal, the PCM will add fuel, resulting in a fuel
trim value above 0%. Some variations in fuel trim values
are normal because all engines are not exactly the same.
If the fuel trim values are greater than +23%, refer to
DTC
P0131, DTC P0151, DTC P0171, and DTC 1171
f o r i t e m s
which can cause a lean HO2S signal.
Idle Air Control (IAC) Valve
The Tech 2 displays the IAC pintle position in counts. A
count of “0” indicates the PCM is commanding the IAC
pintle to be driven all the way into a fully-seated position.
This is usually caused by a large vacuum leak.
The higher the number of counts, the more air is being
commanded to bypass the throttle blade. Refer to IAC
System Check in order to diagnose the IAC system.
Refer to
Rough, Unstable, or Incorrect Idle, Stalling in
Symptoms for other possible causes of idle problems.
Fuel System Pressure Test
A fuel system pressure test is part of several of the
diagnostic charts and symptom checks. To perform this
test, refer to
Fuel Systems Diagnosis.
Fuel Injector Coil Test Procedure and
Fuel Injector Balance Test Procedure
T32003
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2. Relieve the fuel pressure by connecting the
5-8840-0378-0 Fuel Pressure Gauge to the fuel
pressure connection on the fuel rail.
CAUTION: In order to reduce the risk of fire and
personal injury, wrap a shop towel around the fuel
pressure connection. The towel will absorb any fuel
leakage that occurs during the connection of the fuel
pressure gauge. Place the towel in an approved
container when the connection of the fuel pressure
gauge is complete.
Place the fuel pressure gauge bleed hose in an
approved gasoline container.
With the ignition switch “OFF,” open the valve on the
fuel pressure gauge.
3. Record the lowest voltage displayed by the DVM
after the first second of the test. (During the first
second, voltage displayed by the DVM may be
inaccurate due to the initial current surge.)
Injector Specifications:
Resistance Ohms
Voltage Specification at
10
C-35C (50F-95F)
11.8 – 12.65.7 – 6.6
The voltage displayed by the DVM should be within
the specified range.
The voltage displayed by the DVM may increase
throughout the test as the fuel injector windings
warm and the resistance of the fuel injector windings
changes.

6E–63 ENGINE DRIVEABILITY AND EMISSIONS
Injector Coil Test Procedure (Steps 1-6) and Injector Balance Test Procedure
(Steps 7-11)
StepNo Ye s Va l u e ( s ) Action
51. Set injector switch box injector #1.
2. Press the “Push to Start Test” button on the fuel
injector tester.
3. Observe the voltage reading on the DVM.
IMPORTANT:The voltage reading may rise during the
test.
4. Record the lowest voltage observed after the first
second of the test.
5. Set the injector switch box to the next injector and
repeat steps 2, 3, and 4.
Did any fuel injector have an erratic voltage reading
(large fluctuations in voltage that did not stabilize) or a
voltage reading above the specified value?
9.5 VGo to Step 4Go to Step 6
61. Identify the highest voltage reading recorded (other
than those above 9.5 V).
2. Subtract the voltage reading of each injector from
the highest voltage selected in step 1. Repeat until
you have a subtracted value for each injector.
For any injector, is the subtracted Value in step 2
greater than the specified value?
0.6 VGo to Step 4Go to Step 7
7CAUTION: In order to reduce the risk of fire and
personal injury, wrap a shop towel around the
fuel pressure connection. The towel will absorb
any fuel leakage that occurs during the
connection of the fuel pressure gauge. Place the
towel in an approved container when the
connection of the fuel pressure gauge is
complete.
1. Connect the 5-8840-0378-0 Fuel Pressure Gauge
to the fuel pressure test port.
2. Energize the fuel pump using the scan tool.
3. Place the bleed hose of the fuel pressure gauge into
an approved gasoline container.
4. Bleed the air out of the fuel pressure gauge.
5. With the fuel pump running, observe the reading on
the fuel pressure gauge.
Is the fuel pressure within the specified values?
296-376 kPa
(43-55 psi)
Go to Step 8
Go to Fuel
System
Diagnosis
8Turn the fuel pump “OFF.”
Does the fuel pressure remain constant?
—Go to Step 9
Go to Fuel
System
Diagnosis

6E–64
ENGINE DRIVEABILITY AND EMISSIONS
Injector Coil Test Procedure (Steps 1-6) and Injector Balance Test Procedure
(Steps 7-11)
StepNo Ye s Va l u e ( s ) Action
91. Connect the 5-8840-2638-0 Fuel Injector Tester
and 5-8840-2619-0 Injector Switch Box the fuel
injector harness connector.
2. Set the amperage supply selector switch on the fuel
injector tester to the “Balance Test” 0.5–2.5 amp
position.
3. Using the scan tool turn the fuel pump “ON” then
“OFF” in order to pressurize the fuel system.
4. Record the fuel pressure indicated by the fuel
pressure gauge after the fuel pressure stabilizes.
This is the first pressure reading.
5. Energize the fuel injector by depressing the “Push
to Start Test” button on the fuel injector tester.
6. Record the fuel pressure indicated by the fuel
pressure gauge after the fuel pressure gauge
needle has stopped moving. This is the second
pressure reading.
7. Repeat steps 1 through 6 for each fuel injector.
8. Subtract the second pressure reading from the first
pressure reading for one fuel injector. The result is
the pressure drop value.
9. Obtain a pressure drop value for each fuel injector.
10.Add all of the individual pressure drop values. This
is the total pressure drop.
11. Divide the total pressure drop by the number of fuel
injectors. This is the average pressure drop.
Does any fuel injector have a pressure drop value that
is either higher than the average pressure drop or lower
than the average pressure drop by the specified value?
10 kPa
(1.5 psi)
Go to Step 10
Go to OBD
System
Check
10Re-test any fuel injector that does not meet the
specification. Refer to the procedure in step 11.
NOTE: Do not repeat any portion of this test before
running the engine in order to prevent the engine from
flooding.
Does any fuel injector still have a pressure drop value
that is either higher than the average pressure drop or
lower than the average pressure drop by the specified
value?
10 kPa
(1.5 psi)
Go to Step 11
Go to
Symptoms
11Replace the faulty fuel injector(s). Refer to Fuel
Injector.
Is the action complete?—Verify repair—

6E–86
ENGINE DRIVEABILITY AND EMISSIONS
CAUTION: To reduce the risk of fire and personal
injury:
It is necessary to relieve fuel system pressure
before connecting a fuel pressure gauge. Refer to
Fuel Pressure Relief Procedure, below.
A small amount of fuel may be released when
disconnecting the fuel lines. Cover fuel line
fittings with a shop towel before disconnecting, to
catch any fuel that may leak out. Place the towel in
an approved container when the disconnect is
completed.
Fuel Pressure Relief Procedure
1. Remove the fuel cap.
2. Remove the fuel pump relay from the underhood
relay center.
3. Start the engine and allow it to stall.
4. Crank the engine for an additional 3 seconds.
Fuel Gauge Installation
1. Remove the shoulder fitting cap.
2. Install fuel gauge 5-8840-0378-0 to the fuel feed line
located in front of and above the right side valve train
cover .
3. Reinstall the fuel pump relay.
Fuel System Electrical Test
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Read the “Caution” above.
2. Relieve the fuel system pressure and install the fuel
pump pressure gauge to the test fitting.
3. Use Tech 2 to command the fuel pump “ON.”
Is there an immediate pressure build-up which
indicates the pump is running?
—Go to Step 3Go to Step 4
31. Verify that the pump is not running by removing the
fuel filler cap and listening.
2. Command the pump “ON” with Tech 2.
Did the pump turn “OFF” after 2 seconds?
—
Te s t
completed
Go to Step 12
41. Ignition “OFF.”
2. Remove the fuel pump relay.
3. Using a test light connected to ground, probe the
battery feed to the relay.
Did the light illuminate?
—Go to Step 6Go to Step 5
5Repair short or open battery feed to fuel pump relay.
Is the action complete?
—Verify repair—
61. Connect a test light between the two wires that
connect to the fuel pump relay pull-in coil.
2. Ignition “ON.”
Did the test light illuminate for 2 seconds and then turn
off?
—Go to Step 12Go to Step 7
71. With a test light connected to battery (–), probe the
fuel pump relay connector at the wire which runs
from the relay pull-in coil to the PCM.
2. Ignition “ON.”
Did the test light illuminate for 2 seconds and then turn
off?
—Go to Step 8Go to Step 9
8Locate and repair open in the fuel pump relay ground
circuit.
Is the action complete?
—Verify repair—

6E–105 ENGINE DRIVEABILITY AND EMISSIONS
The engine oil dip stick not fully seated.
The engine oil fill cap loose or missing.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. The MAF system performance or “rationality”
diagnostic uses the MAP sensor signal along with
other input to calculate an expected airflow rate that
is then compared to the actual measured airflow
from the MAF sensor. The first few steps of this
table verify that the MAP sensor is working properly.
6. Using Freeze Frame and/or Failure Records data
may aid in locating an intermittent condition. If the
DTC cannot be duplicated, the information included
in the Freeze Frame and/or Failure Records data
can be useful in determining how many miles since
the DTC set. The Fail Counter and Pass Counter
can also be used to determine how many ignition
cycles the diagnostic reported a pass and/or a fail.
Operate the vehicle within the same Freeze Frame
conditions (RPM, load, vehicle speed , temperature,
etc.) that were noted. This will isolate when the
DTC failed.For any test that requires back probing the PCM or
component harness connectors, use the Connector
Test Adapter Kit J 35616-A. Using this kit will
prevent any damage to the harness connector
terminals.
7. Any un-metered air may cause this DTC to set.
Check the PVC system for vacuum leaks. Also
inspect the dip stick for being pulled out. Check the
oil fill cap for being loose.
8. Verifies the signal circuit from the MAF sensor
electrical connector to the PCM.
9. Verifies whether a ground and B+ circuit is available.
10. Checks a signal circuit for an open.
11. Checks for a signal circuit shorted to B+.
DTC P0101 – MAF System Performance
StepActionVa l u e ( s )Ye sNo
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2
Go to OBD
System
Check
21. Ignition “ON,” engine “OFF.”
2. Using a Tech 2, select “MAP” from the Engine 1
Data List.
Is the value displayed greater than the value shown?
85 kPaGo to Step 3Go toStep 13
31. Remove the MAP sensor from the intake manifold
but leave the electrical harness connected.
2. Connect a hand operated vacuum pump to the MAP
sensor.
3. Observe the MAP display while slowly applying
vacuum up to 20” Hg as indicated on the pump
gauge.
Each 1” of vacuum applied should result in a 3 to 4 kPa
drop in the MAP sensor value on the Tech 2 and the
value should change smoothly with each increase in
vacuum.
Did the MAP value change smoothly through the entire
range of the test without any erratic readings?
—Go to Step 13Go to Step 4
4With 20” Hg vacuum applied to the MAP sensor, is the
MAF sensor reading the same or less than the value
shown?
34 kPaGo to Step 5Go to Step 13
5Disconnect the vacuum source from the MAP sensor.
Does the MAP sensor reading return to its original
value?
—Go to Step 6Go to Step 13

6E–315 ENGINE DRIVEABILITY AND EMISSIONS
Installation Procedure
1. Install the O-ring backup on the fuel injector.
2. Install the new O-ring on the fuel injector.
3. Install the fuel injector on the fuel rail.
055RW009
4. Use new fuel injector retainer clips to retain the fuel
injector to the fuel rail.
5. Coat the end of the fuel injector with engine oil.
6. Install the fuel rail. Refer to
Fuel Rail.
014RW164
7. Install the upper intake manifold. Refer to Common
Chamber in Engine Mechanical.
8. Install the engine cover.
9. Connect the negative battery cable.
Fuel Pressure Regulator
Removal Procedure
CAUTION: To reduce the risk of fire and personal
injury, it is necessary to relieve the fuel system
pressure before servicing the fuel system
components.
CAUTION: After relieving the system pressure, a
small amount of fuel may be released when servicing
fuel lines or connections. Reduce the chance of
personal injury by covering the fuel line fittings with
a shop towel before disconnecting the fittings. The
towels will absorb any fuel that may leak out. When
the disconnect is completed, place the towel in an
approved container.
NOTE: Compressed air must never be used to test or
clean a fuel pressure regulator, as damage to the fuel
pressure regulator may result.
NOTE: To prevent damage to the fuel pressure regulator,
do not immerse the pressure regulator in solvent.
1. Depressurize the fuel system. Refer to
Fuel Pressure
Relief Procedure
.
2. Disconnect the negative battery cable.
3. Remove the fuel pump relay. Refer to
Fuel Pump
Relay
.
4. Remove the pressure regulator hose from the fuel
pressure regulator.
014RW110