engine mount ISUZU KB P190 2007 Workshop Repair Manual

6E–64 ENGINE DRIVEABILITY AND EMISSIONS
– Are there areas subjected to vibration ormovement (engine, transmission or
suspension)?
– Are there areas exposed to moisture, road salt or other corrosives (battery acid, oil or other
fluids)?
– Are there common mounting areas with other systems/components?
– Have previous repairs been performed to wiring, connectors, components or mounting areas
(causing pinched wires between panels and
drivetrain or suspension components without
causing and immediate problem)?
– Does the vehicle have aftermarket or dealer- installed equipment (radios, telephone, etc.)
Step 2: Isolate the problem
At this point, you should have a good idea of what could
cause the present condition, as well as could not cause
the condition. Actions to take include the following:
• Divide (and separate, where possible) the system or circuit into smaller sections
• Confine the problem to a smaller area of the vehicle (start with main harness connections while removing
panels and trim as necessary in order to eliminate
large vehicle sections from further investigation)
• For two or more circuits that do not share a common power or ground, concentrate on areas where
harnesses are routed together or connectors are
shared (refer to the following hints)
Hints
Though the symptoms may vary, basic electrical failures
are generally caused by:
• Loose connections: – Open/high resistance in terminals, splices,connectors or grounds
• Incorrect connector/harness routing (usually in new vehicles or after a repair has been made):
– Open/high resistance in terminals, splices, connectors of grounds
• Corrosion and wire damage:
– Open/high resistance in terminals, splices,connectors of grounds
• Component failure: – Opens/short and high resistance in relays,modules, switches or loads
• Aftermarket equipment affecting normal operation of other systems
You may isolate circuits by:
• Unplugging connectors or removing a fuse to separate one part of the circuit from another part
• Operating shared circuits and eliminating those that function normally from the suspect circuit
• If only one component fails to operate, begin testing at the component
• If a number of components do no operate, begin tests at the area of commonality (such as power sources,
ground circuits, switches or major connectors)
What resources you should use
Whenever appropriate, you should use the following
resources to assist in the diagnostic process:
• Service manual
• Technical equipment (for data analysis)
• Experience
• Technical Assistance
• Circuit testing tools
5d. Intermittent Diagnosis
By definition, an intermittent problem is one that does
not occur continuously and will occur when certain
conditions are met. All these conditions, however, may
not be obvious or currently known. Generally,
intermittents are caused by:
• Faulty electrical connections and wiring
• Malfunctioning components (such as sticking relays, solenoids, etc.)
• EMI/RFI (Electromagnetic/radio frequency interference)
• Aftermarket equipment
Intermittent diagnosis requires careful analysis of
suspected systems to help prevent replacing good
parts. This may involve using creativity and ingenuity to
interpret customer complaints and simulating all
external and internal system conditions to duplicate the
problem.
What you should do
Step 1: Acquire information
A thorough and comprehensive customer check sheet
is critical to intermittent problem diagnosis. You should
require this, since it will dictate the diagnostic starting
point. The vehicle service history file is another
source for accumulating information about the
complaint.
Step 2: Analyze the intermittent problem
Analyze the customer check sheet and service history
file to determine conditions relevant to the suspect
system(s).
Using service manual information, you must identify,
trace and locate all electrical circuits related to the
malfunctioning system(s). If there is more than one
system failure, you should identify, trace and locate
areas of commonality shared by the suspect circuits.

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6E–72 ENGINE DRIVEABILITY AND EMISSIONS
TYPICAL SCAN DATA & DEFINITIONS (ENGINE DATA)
Use the Typical Values Table only after the On-Board Diagnostic System Check has been completed, no DTC(s) were
noted, and you have determined that the on-board diagnostics are functioning properly. Tech 2 values from a
properly-running engine may be used for comparison with the engine you are diagnosing.
Condition : Vehicle stopping, engine running, air conditioning off & after warm-up (Coolant temperature approximately
80 deg.)
Tech 2 ParameterUnitsIdle2000rpmDescription
1 Engine Speed rpm775 - 8751950 - 2050 The actual engine speed is measured by ECM from the
CKP sensor 58X signal.
2 Desired Idle Speed rpm825800 - 850 The desired engine idle speed that the ECMcommanding. The ECM compensates for various engine
loads.
3 Engine Coolant Temperature °C or °F80 - 9080 - 90 The ECT is measured by ECM from ECT sensor output
voltage. When the engine is normally warm upped, this
data displays approximately 80 °C or more.
4 Start Up ECT (Engine Coolant Temperature) °C or °FDepends on ECT
at start-upDepends on ECT at start-up Start-up ECT is measured by ECM from ECT sensor
output voltage when engine is started.
5Intake Air
Temperature °C or °FDepends on
ambient tempDepends on
ambient temp The IAT is measured by ECM from IAT sensor output
voltage. This data is changing by intake air temperature.
6 Start Up IAT (Intake Air Temperature) °C or °FDepends on IAT at
start-upDepends on IAT at start-up Start-up IAT is measured by ECM from IAT sensor output
voltage when engine is started.
7 Manifold Absolute Pressure kPa31 - 3625 - 30The MAP (kPa) is measured by ECM from MAP output
voltage. This data is changing by inlet manifold pressure.
8 Barometric Pressure kPaDepends on altitudeDepends on altitude The barometric pressure is measured by ECM from the
MAP sensor output voltage monitored during key up and
wide open throttle. This data is changing by altitude.
9 Throttle Position %02-4 Throttle position operating angle is measured by the ECM from throttle position output voltage. This should
display 0% at idle and 99 - 100% at full throttle.
10 Calculated Air Flow g/s3.5 -4.508.0 - 10.0 This displays calculated air mount from MAP sensor output. This data is changing by inlet manifold pressure.
11 Air Fuel Ratio14.6:114.6:1 This displays the ECM commanded value. In closed loop,this should normally be displayed around 14.2:1 - 14.7:1.
12 Spark Advance °CA8 - 1525 - 32 This displays the amount of spark advance being commanded by the ECM.
13 Engine Load %2 - 55 - 10 This displays is calculated by the ECM form engine
speed and MAF sensor reading. Engine load should
increase with an increase in engine speed or air flow
amount.
14 Injection Pulse Width ms1.0 - 3.0 3.0 - 4.0 This displays the amount of time the ECM is commanding each injector On during each engine cycle.
A longer injector pulse width will cause more fuel to be
delivered. Injector pulse width should increase with
increased engine load.
15 Fuel System Status Open Loop/ Close LoopClose LoopClose Loop When the engine is first started the system is in “OpenLoop” operation. In “Open Loop”, the ECM ignores the
signal from the oxygen sensors. When various conditions
(ECT, time from start, engine speed & oxygen sensor
output) are met, the system enters “Closed Loop”
operation. In “Closed Loop”, the ECM calculates the air
fuel ratio based on the signal from the oxygen sensors.
16 Knock Present Yes/NoNoNo This displays knock sensor detection status. When engine knock is occurred, displays "Yes".
17 Knock Counter--This displays the number of knock during a ignition cycle.
18 Knock Retard °CA00 This displays the commanded ignition spark timing retard
timing based on the signal from the knock sensor.
19 A/C Clutch Relay On/OffOffOff This displays whether the ECM has commanded the A/C compressor clutch “On” or “Off”.

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6E–74 ENGINE DRIVEABILITY AND EMISSIONS
TYPICAL SCAN DATA & DEFINITIONS (O2 SENSOR DATA)
Use the Typical Values Table only after the On-Board Diagnostic System Check has been completed, no DTC(s) were
noted, and you have determined that the on-board diagnostics are functioning properly. Tech 2 values from a
properly-running engine may be used for comparison with the engine you are diagnosing.
Condition : Vehicle stopping, engine running, air conditioning off & after warm-up (Coolant temperature approximately
80 deg.)
Tech 2 ParameterUnitsIdle2000rpmDescription
1 Engine Speed rpm710 - 8751950 - 2050 The actual engine speed is measured by ECM from the
CKP sensor 58X signal.
2 Desired Idle Speed rpm825800 - 850 The desired engine idle speed that the ECMcommanding. The ECM compensates for various engine
loads.
3 Engine Coolant Temperature °C or °F80 - 9080 - 90 The ECT is measured by ECM from ECT sensor output
voltage. When the engine is normally warm upped, this
data displays approximately 80 °C or more.
4 Start Up ECT (Engine Coolant Temperature) °C or °FDepends on ECT
at start-upDepends on ECT at start-up Start-up ECT is measured by ECM from ECT sensor
output voltage when engine is started.
5Intake Air
Temperature °C or °FDepends on
ambient tempDepends on
ambient temp The IAT is measured by ECM from IAT sensor output
voltage. This data is changing by intake air temperature.
6 Start Up IAT (Intake Air Temperature) °C or °FDepends on IAT at
start-upDepends on IAT at start-up Start-up IAT is measured by ECM from IAT sensor output
voltage when engine is started.
7 Manifold Absolute Pressure kPa31 - 3625 - 30The MAP (kPa) is measured by ECM from MAP output
voltage. This data is changing by inlet manifold pressure.
8 Barometric Pressure kPaDepends on altitudeDepends on altitude The barometric pressure is measured by ECM from the
MAP sensor output voltage monitored during key up and
wide open throttle. This data is changing by altitude.
9 Throttle Position %02 - 4 Throttle position operating angle is measured by the ECM from throttle position output voltage. This should
display 0% at idle and 99 - 100% at full throttle.
10 Calculated Air Flow g/s3.5 -4.508.0 - 10.0 This displays intake air amount. The mass air flow is measured by ECM from the MAF sensor output voltage.
11 Air Fuel Ratio14.6:114.6:1 This displays the ECM commanded value. In closedloop, this should normally be displayed around 14.2:1 -
14.7:1.
12 Fuel System Status Open Loop/ Close LoopClose LoopClose Loop When the engine is first started the system is in “OpenLoop” operation. In “Open Loop”, the ECM ignores the
signal from the oxygen sensors. When various
conditions (ECT, time from start, engine speed & oxygen
sensor output) are met, the system enters “Closed Loop”
operation. In “Closed Loop”, the ECM calculates the air
fuel ratio based on the signal from the oxygen sensors.
13 Engine Load %2 - 55 - 10 This displays is calculated by the ECM form engine
speed and MAF sensor reading. Engine load should
increase with an increase in engine speed or air flow
amount.
14B1 O2 Sensor Ready
(Bank 1)Ye s / N oYe sYes This displays the status of the exhaust oxygen sensor. This display will indicate “Yes” when the ECM detects a
fluctuating oxygen sensor output voltage sufficient to
allow closed loop operation. This will not occur unless
the oxygen sensor is warmed up.
15B1S1 Status
(Bank 1 Sensor 1)Rich / LeanRich / LeanRich / Lean This displays dependent on the exhaust oxygen sensor output voltage. Should fluctuate constantly “Rich” and
“Lean” in closed loop.
16 Fuel Trim Learned Yes/NoYe sYes When conditions are appropriate for enabling long term fuel trim corrections, fuel trim learn will display “Yes”.
This indicates that the long term fuel trim is responding
to the short term fuel trim. If the fuel trim lean displays
“No”, then long term fuel trim will not respond to changes
in short term fuel trim.

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ENGINE DRIVEABILITY AND EMISSIONS 6E–75
17 Fuel Trim Cell15 - 201 - 2 This displays dependent on engine speed and calculatedintake air flow reading. A plot of engine speed versus
intake air flow amount is divided into the cells. Fuel trim
cell indicates which cell is currently active.
18B1S1 O2 Sensor
(Bank1 Sensor 1)mV50 - 95050 -950 This displays the exhaust oxygen sensor output voltage. Should fluctuate constantly within a range between
10mV (lean exhaust) and 1000mV (rich exhaust) while
operating in closed loop.
19B1 Short Term Fuel
Trim (Bank 1)%-6 - 0-6 - 0 The short term fuel trim to a bank represents a short term correction to the bank fuel delivery by the ECM in
response to the amount of time the bank fuel control
oxygen sensor voltage spends above or below the
450mV threshold. If the oxygen sensor voltage has
mainly remained less than 450mV, indicating a lean air/
fuel, short term fuel trim will increase into the positive
range above 0% and the ECM will pass fuel. If the
oxygen sensor voltage stays mainly above the threshold,
short term fuel trim will decrease below 0% into the
negative range while the ECM reduces fuel delivery to
compensate for the indicated rich condition. Under
certain conditions such as extended idle and high
ambient temperatures, canister purge may cause short
term fuel trim to read in the negative range during normal
operation. Fuel trim values at maximum authority may
indicate an excessively rich or lean system.
20B1 Long Term Fuel
Trim (Bank 1)%-10 - 0-5 - 0 The long term fuel trim is delivered from the short term fuel term values and represents a long term correction of
fuel delivery for bank in question. A value of 0% indicates
that fuel delivery requires no compensation to maintain
the ECM commanded air fuel ratio. A negative value
indicates that the fuel system is rich and fuel delivery is
being reduced (decreased injector pulse width). A
positive value indicates that a lean condition exists and
the ECM is compensating by add fuel (increased injector
pulse width). Because long term fuel trim tends to follow
short term fuel trim, a value in the negative range due to
canister purge at idle should not be considered unusual.
Fuel trim values at maximum authority may indicate an
excessively rich or lean system.
21Injection Pulse Widthms3.0 - 1.03.0 - 4.0 This displays the amount of time the ECM is commanding each injector On during each engine cycle.
A longer injector pulse width will cause more fuel to be
delivered. Injector pulse width should increase with
increased engine load.
22Power EnrichmentYe s / N oNoNo The ECM provides the extra amount of fuel when it detects a rapid increase in the throttle position and air
flow (Power Enrichment). Under this condition the ECM
should detect a “rich condition (high oxygen sensor
voltage).
23Deceleration Fuel
Cutoff Active/
InactiveInactiveInactiveThe ECM reduces the amount of fuel injected when it
detects a decrease in the throttle position and the air
flow. When deceleration is very fast, the ECM may cut off
fuel completely. Until enable conditions meet the engine
revolution less than 1000rpm or MAP less than 10kPa.
24Time From Start--This displays the engine time elapsed since the engine
was started. If the engine is stopped, engine run time will
be reset to 00:00:00
Tech 2 ParameterUnitsIdle2000rpmDescription

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ENGINE DRIVEABILITY AND EMISSIONS 6E–99
• An erratic voltage reading (large fluctuations involtage that do not stabilize) indicates an
intermittent connection within the fuel injector.
5. Injector Specifications: 7. The Fuel Injector Balance Test portion of this chart
(Step 7 through Step 11) checks the mechanical (fuel
delivery) portion of the fuel injector. An engine
cooldown period of 10 minutes is necessary in order
to avoid irregular fuel pressure readings due to “Hot
Soak” fuel boiling.
Injector Coil Test Procedure (Steps 1-6) and Injector Balance Test Procedure (Steps 7-11)
NOTE: These figures are examples only. Highest Acceptable Voltage
Reading Above/Below
35°C/10°C (95°F/50°F) Acceptable
Subtracted Value
9.5Volts 0.6Volt
CYLINDER
1234
1st Reading (1) 296kPa (43psi)296kPa
(43psi) 296kPa
(43psi) 296kPa
(43psi)
2nd Reading (2) 205kPa (29psi)205kPa
(29psi) 196kPa
(28psi) 274kPa
(39psi)
Amount of Drop
(1st Reading-2nd Reading) 91kPa
(14psi) 91kPa
(14psi) 100kPa
(15psi) 22kPa
(4psi)
Av. Drop = 166kPa/24psi ±10kPa/1.5psi
= 156 - 176kPa or 22.5 - 25.5psi Faulty, Lean
(Too Little Fuel Drop) Faulty, Lean
(Too Little Fuel Drop) Faulty, Lean
(Too Little Fuel Drop) Faulty, Lean
(Too Little Fuel Drop)

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ENGINE DRIVEABILITY AND EMISSIONS 6E–103
FUEL SYSTEM ELECTRICAL TEST
Circuit Description
When the ignition switch is first turned ON, the engine
control module (ECM) energizes the fuel pump relay
which applies power to the in-tank fuel pump. The fuel
pump relay will remain ON as long as the engine is
running or cranking and the ECM is receiving 58X
crankshaft position pulses. If no 58X crankshaft position
pulses are present, the ECM de-energizes the fuel
pump relay within 2 seconds after the ignition is turned
ON or the engine is stopped.
The fuel pump delivers fuel to the fuel rail and injectors,
then to the fuel pressure regulator. The fuel pressure
regulator controls fuel pressure by allowing excess fuel
to be returned to the fuel tank. With the engine stopped
and ignition ON, the fuel pump can be turned ON by
using a command by the scan tool.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed-through wire insulation, or a wire broken inside
the insulation. Check for the following items:
• Poor connection or damaged harness - Inspect the ECM harness and connectors for improper mating,
broken locks, improperly formed or damaged
terminals, poor terminal-to-wire connection, and
damaged harness. 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.

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6E–108 ENGINE DRIVEABILITY AND EMISSIONS
FUEL SYSTEM DIAGNOSIS
Circuit Description
When the ignition switch is turned ON, the engine
control module (ECM) will turn ON the in-tank fuel
pump. The in-tank fuel pump will remain ON as long as
the engine is cranking or running and the ECM is
receiving 58X crankshaft position pulses. If there are no
58X crankshaft position pulses, the ECM will turn the in-
tank fuel pump OFF 2 seconds after the ignition switch
is turned ON or 2 seconds after the engine stops
running.
The in-tank fuel pump is an electric pump within an
integral reservoir. The in-tank fuel pump supplies fuel
through an in-line fuel filter to the fuel rail assembly. The
fuel pump is designed to provide fuel at a pressure
above the pressure needed by the fuel injectors. A fuel
pressure regulator, attached to the fuel rail, keeps the
fuel available to the fuel injectors at a regulated
pressure. Unused fuel is returned to the fuel tank by a
separate fuel return line.
Te s t D e s c r i p t i o n
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. Connect the fuel pressure gauge to the fuel feed line as shown in the fuel system illustration. Wrap a shop
towel around the fuel pressure connection in order to
absorb any duel leakage that may occur when
installing the fuel pressure gauge. With the ignition
switch ON and the fuel pump running, the fuel
pressure indicated by the fuel pressure gauge
should be 283-376 kPa (41-55 psi). This pressure is
controlled by the amount of pressure the spring
inside the fuel pressure regulator can provide.
3. A fuel system that cannot maintain a constant fuel pressure has a leak in one or more of the following
areas:
• The fuel pump check valve.
• The fuel pump flex line.
• The valve or valve seat within the fuel pressure regulator.

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ENGINE DRIVEABILITY AND EMISSIONS 6E–109
• The fuel injector(s).
4. Fuel pressure that drops off during acceleration, cruise, or hard cornering may case a lean condition.
A lean condition can cause a loss of power, surging,
or misfire. A lean condition can be diagnosed using a
Tech 2 Scan Tool.
Following are applicable to the vehicle with
closed Loop System:
If an extremely lean condition occurs, the oxygen
sensor(s) will stop toggling. The oxygen sensor
output voltage(s) will drop below 500 mV. Also, the
fuel injector pulse width will increase.
Important: Make sure the fuel system is not
operating in the “Fuel Cut-Off Mode.”
When the engine is at idle, the manifold pressure is
low (high vacuum). This low pressure (high vacuum)
is applied to the fuel pressure regulator diaphragm.
The low pressure (high vacuum) will offset the
pressure being applied to the fuel pressure regulator
diaphragm by the spring inside the fuel pressure
regulator. When this happens, the result is lower fuel
pressure. The fuel pressure at idle will vary slightly
as the barometric pressure changes, but the fuel
pressure at idle should always be less than the fuel
pressure noted in step 2 with the engine OFF.
16.Check the spark plug associated with a particular
fuel injector for fouling or saturation in order to
determine if that particular fuel injector is leaking. If
checking the spark plug associated with a particular
fuel injector for fouling or saturation does not
determine that a particular fuel injector is leaking,
use the following procedure:
• Remove the fuel rail, but leave the fuel lines and injectors connected to the fuel rail. Refer to Fuel
Rail Assembly in On-Vehicle Service .
• Lift the fuel rail just enough to leave the fuel injector nozzles in the fuel injector ports.
Caution: In order to reduce the risk of fire and
personal injury that may result from fuel
spraying on the engine, verify that the fuel rail is
positioned over the fuel injector ports and verify
that the fuel injector retaining clips are intact.
• Pressurize the fuel system by connecting a 20 amp fused jumper between B+ and the fuel
pump relay connector.
• Visually and physically inspect the fuel injector nozzles for leaks.
17.A rich condition may result from the fuel pressure being above 376 kPa (55 psi). A rich condition may
cause a 45 to set. Driveability conditions associated with rich conditions can include hard starting
(followed by black smoke) and a strong sulfur smell
in the exhaust.
20.This test determines if the high fuel pressure is due to a restricted fuel return line or if the high fuel
pressure is due to a faulty fuel pressure regulator.
21.A lean condition may result from fuel pressure below 333 kPa (48 psi). A lean condition may cause a 44 to
set. Driveability conditions associated with lean
conditions can include hard starting (when the
engine is cold), hesitation, poor driveability, lack of
power, surging, and misfiring.
22.Restricting the fuel return line causes the fuel pressure to rise above the regulated fuel pressure.
Command the fuel pump ON with the scan tool. The
fuel pressure should rise above 376 kPa (55 psi) as
the fuel return line becomes partially closed.
NOTE: Do not allow the fuel pressure to exceed 414
kPa (60 psi). Fuel pressure in excess of 414 kPa (60
psi) may damage the fuel pressure regulator. 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. Located on the intake manifold which is at the top right part of the engine.
3. Start the engine and allow it to stall.
4. Crank the engine for an additional 3 seconds.
Fuel Pressure Gauge Installation
1. Remove the fuel pressure fitting cap.
2. Install fuel pressure gauge 5-8840-0378-0 to the fuel feed line located on the upper right side of the
engine.
3. Reinstall the fuel pump relay.

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6E–110 ENGINE DRIVEABILITY AND EMISSIONS
Fuel System Diagnosis
StepAction Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check” performed? — Go to Step 2Go to
OBD
System Check
2 1. Turn the ignition OFF. 2. Turn the air conditioning system OFF.
3. Relieve fuel system pressure and install the fuel pressure gauge.
4. Turn the ignition ON.
NOTE: The fuel pump will run for approximately 2
seconds. Use the Scan Tool to command the fuel
pump ON.
5. Observe the fuel pressure indicated by the fuel pressure gauge with the fuel pump running.
Is the fuel pressure within the specified limits? 283-376 kPa
(41-55 psi) Go to Step 3Go to Step 17
3 Does the fuel pressure indicated by the fuel pressure gauge remain constant?
NOTE: The fuel pressure will drop when the fuel
pump stops running, then it should stabilize and
remain constant. — Go to Step 4Go to Step 12
4 1. When the vehicle is at normal operating temperature, turn the ignition ON to build fuel
pressure and observe the measurement on the
gauge.
2. Start the engine and observe the fuel pressure gauge.
Did the reading drop by the amount specified after the
engine was started? 21-105 kPa
(3-15 psi) Go to Step 5Go to Step 9
5 Is fuel pressure dropping off during acceleration, cruise, or hard cornering? — Go to Step 6Check for
improper fuel
6 Visually and physically inspect the following items for a restriction:
• The in-line fuel filter.
• The fuel feed line.
Was a restriction found? — Verify repair Go to Step 7
7 Remove the fuel tank and visually and physically inspect the following items:
• The fuel pump strainer for a restriction.
• The fuel line for a leak.
• Verify that the correct fuel pump is in the vehicle.
Was a problem found in any of these areas? — Verify repair Go to Step 8
8 Replace the fuel pump. Is the action complete? — Verify repair —
9 1. Disconnect the vacuum hose from the fuel pressure regulator.
2. With the engine idling, apply 12-14 inches of vacuum to the fuel pressure regulator.
Does the fuel pressure indicated by the fuel pressure
gauge drop by the amount specified? 21-105 kPa
(3-15 psi) Go to Step 10Go to Step 11

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6E–136 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0117 ENGINE COOLANT TEMPERATURE SENSOR LOW INPUT
Condition for setting the DTC and action taken when the DTC sets
Circuit Description
The engine coolant temperature (ECT) sensor is a
thermistor mounted in the engine coolant stream. The
engine control module (ECM) applies a voltage (about 5
volts) through a pull-up resistor to the ECT signal circuit.
When the engine coolant is cold, the sensor (thermistor)
resistance is high, therefore the ECM will measure a
high signal voltage. As the engine coolant warms, the
sensor resistance becomes lower, and the ECT signal
voltage measured at the ECM drops. Diagnostic Trouble
code P0117 set when the ECM detects an excessively
low signal voltage on the engine coolant temperature
sensor signal circuit.
Diagnostic Aids
Check for the following conditions:
• Poor connection at ECM - Inspect harness connectors for backed-out terminals, improper
mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connection.
• Damaged harness - Inspect the wiring harness for damage, short to ground, short to battery positive,
and open circuit. If the harness appears to be OK,
observe the ECT display on the Tech 2 while moving
connectors and wiring harnesses related to the ECT
sensor. A change in the ECT display will indicate the
location of the fault.
Code Type DTC Name DTC Setting Condition Fail-Safe (Back Up)
P0117 A Engine Coolant Temperature Sensor Low Input 1. Engine run time is longer than 120 sec-
onds.
2. ECT sensor output is more than 149 deg. C. The ECM uses default engine coolant
temperature value based on intake air
temperature and engine run time.

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