check engine ISUZU KB P190 2007 Workshop Repair Manual

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-45
Diagnostic System Check - Engine Controls
Description
The Diagnostic System Check - Engine Controls is an
organized approach to identifying a condition that is
created by a malfunction in the electronic engine
control system. The Diagnostic System Check must be
the starting point for any driveability concern. The
Diagnostic System Check directs the service technician
to the next logical step in order to diagnose the
concern. Understanding and correctly using the
diagnostic table reduces diagnostic time, and prevents
the replacement of good parts.
Test Description
The numbers below refer to the step numbers on the
diagnostic table.
2. Lack of communication may be because of a partial
or a total malfunction of the serial data circuit.
7. The presence of DTCs which begin with U, indicate
that some other module is not communicating.
10. If there are other modules with DTCs set, refer to
the DTC list. The DTC list directs you to the appropriate
diagnostic procedure. If the control module stores
multiple DTCs, diagnose the DTCs in the following
order:
• Component level DTCs, such as sensor DTCs, solenoid DTCs, actuator DTCs, and relay DTCs.
Diagnose the multiple DTCs within this category in
numerical order. Begin with the lowest numbered
DTC, unless the diagnostic table directs you
otherwise. Diagnostic System Check Engine Controls
Important:
• DO NOT perform this diagnostic if there is not a driveability concern, unless another procedure
directs you to this diagnostic.
• Before you proceed with diagnosis, search for applicable service bulletins.
• Unless a diagnostic procedure instructs you, DO NOT clear the DTCs.
• If there is a condition with the starting system, refer to the starting system section in the engine
mechanical.
• Ensure the battery has a full charge.
• Ensure the battery cables (+) (-) are clean and tight.
• Ensure the ECM grounds are clean, tight, and in the correct location.
• Ensure the ECM harness connectors are clean and correctly connected. DO NOT attempt to
crank the engine with ECM harness connectors
disconnect.
• Ensure the ECM terminals are clean and correctly mating.
• Ensure the fuel injector ID code data is correctly programmed in to the ECM.
• Ensure the immobilizer security information is correctly programmed into the ECM and
immobilizer control unit (ICU).
• If there are fuel system DTC’s (P0087, P0088, P0089, P0093, P1093 or P1094), diagnose sensor
DTCs, solenoid DTCs, actuator DTCs and relay
DTCs first.
Diagnostic System Check - Engine Controls
Step Action Value(s)Yes No
1 Install a scan tool.
Does the scan tool turn ON? —
Go to Step 2 Go to Scan Tool
Does Not Power Up
2 1. Turn ON the ignition, with the engine OFF.
2. Attempt to establish communication with the listed control modules.
•ECM
• Immobilizer control unit (ICU) (If so equipped)
• Transmission control module (TCM) (AISIN A/T only)
Does the scan tool communicate with all the listed
control modules? —
Go to Step 3 Go to Scan Tool
Does Not
Communicate with CAN Device

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ISUZU KB P190 2007

6E-46 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
3Notice:
If an immobilizer system is active the ECM
will disable the fuel injection causing the engine to
stall immediately after starting and energize the
starter cut relay to disable cranking.
Attempt to crank the engine.
Does the engine crank? —
Go to Step 4 Go to Step 5
4 Attempt to start the engine.
Does the engine start and idle? —
Go to Step 6 Go to Engine
Cranks but Does
Not Run
5 Does the scan tool display ECM DTCs P0615,
P0633, P161B or U0167?
—
Go to Applicable DTC Problem is relating
to starting system. Refer to the
applicable
diagnostic chart in starting system
6 Select the DTC display function for the following
control modules: •ECM
• ICU (If so equipped)
• TCM (AISIN A/T only)
Does the scan tool display any DTCs? —
Go to Step 7 Go to Step 11
7 Does the scan tool display DTCs which begin with
U or other control module communication fault
DTCs? —
Go to Applicable
DTC Go to Step 8
8 Does the scan tool display ECM DTCs P0601,
P0602, P0604, P0606 or P1621? —Go to Applicable
DTC Go to Step 9
9 Does the scan tool display ECM DTCs P0562 or
P0563, P156A or P156B? —
Go to Applicable
DTC Go to Step 10
10 Is there any other code in any controller that has
not been diagnosed? —Go to Applicable
DTC Go to Step 11
11 Is the customer’s concern with the automatic
transmission? —Go to Diagnostic
System Check - Transmission
Controls Go to Step 12
12 Is the customer’s concern with the immobilizer
system? —Go to Diagnostic
System Check - Immobilizer
Controls Go to Step 13
13 1. Review the following symptoms.
2. Refer to the applicable symptom diagnostic table:
• Hard Start
• Rough, Unstable, or Incorrect Idle and Stalling
• High Idle Speed
•Cuts Out
• Surges
• Lack of Power, Sluggishness, or Sponginess
• Hesitation, Sag, Stumble
• Abnormal Combustion Noise
• Poor Fuel Economy
• Excessive Smoke (Black Smoke)
• Excessive Smoke (White Smoke)
Did you find and correct the condition? —
System OK Go to Intermittent
Conditions
Step
Action Value(s)Yes No

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-47
Scan Tool Data List
The Engine Scan Tool Data List contains all engine
related parameters that are available on the scan tool.
A given parameter may appear in any one of the data
lists, and in some cases may appear more than once,
or in more than one data list in order to group certain
related parameters together. Use the Engine Scan Tool
Data List only after the following is determined:
• The Engine Controls - Diagnostic System Check is completed. • On-board diagnostics are functioning properly.
Scan tool values from a properly running engine may
be used for comparison with the engine you are
diagnosing. The Engine Scan Tool Data List represents
values that would be seen on a normal running engine.
Only the parameters listed below are referenced in this
service manual for use in diagnosis.
Scan Tool Parameter Units Displayed Typical Data Value at Engine Idle Typical Data Value at 2000RPM
Operating Conditions: Engine idling or 2000RPM/ Engine coolant temperature is between 75 to 85 °C (167 to 185 °F)/
Accelerator pedal is constant/ Neutral or Park/ Accessories OFF/ Vehicle located at sea level
Engine Speed RPMNearly 700 RPM Nearly 2000 RPM
Desired Engine Idle Speed RPM700 RPM 700 RPM
Calculated Engine Load %- -
Coolant Temperature °C/ °F 75 to 85 °C/ 167 to 185 °F 75 to 85 °C/ 167 to 185 °F
Engine Coolant Temperature Sensor Volts
0.4 to 0.6 volts 0.4 to 0.6 volts
Intake Air Temperature °C/ °F 20 to 40 °C/ 68 to 104 °F 20 to 40 °C/ 68 to 104 °F
Intake Air Temperature Sensor Volts 1.4 to 2.3 volts1.4 to 2.3 volts
Fuel Temperature °C/ °F 20 to 60 °C/ 68 to 140 °F 20 to 60 °C/ 68 to 140 °F
Fuel Temperature Sensor Volts0.8 to 2.3 volts 0.8 to 2.3 volts
MAF (Mass Air Flow) g/sec300 to 600 g/sec 200 to 600 g/sec
MAF Sensor (Mass Air Flow) Volts1.2 to 1.6 volts 2.0 to 2.7 volts
Barometric Pressure kPa/psi Nearly 100 kPa/ 14.5 psi at sea
levelNearly 100 kPa/ 14.5 psi at sea
level
Barometric Pressure Sensor VoltsNearly 2.3 volts at sea level Nearly 2.3 volts at sea level
Turbocharger Solenoid Command %
50 to 60 % 50 to 60 %
Desired Boost Pressure kPa/ psi Nearly 100 kPa/ 14.5 psi at sea
levelLess than 120 kPa/ 17.4 psi
Boost Pressure kPa/ psi Nearly 100 kPa/ 14.5 psi at sea
levelLess than 120 kPa/ 17.4 psi
Boost Pressure Sensor VoltsNearly 1.0 volt Less than 1.3 volts
Desired Fuel Rail Pressure MPa/ psi 30 MPa/ 4,350 psiMore than 70 MPa/ 10,200 psi
(4JJ1 Euro 4 specification)
More than 50 MPa/ 7,250 psi
(4JJ1 except Euro 4 specification)
More than 60 MPa/ 8,700 psi
(4JK1)
Fuel Rail Pressure MPa/ psi 27 to 33 MPa/ 3,900 to 4,800 psi More than 70 MPa/ 10,200 psi
(4JJ1 Euro 4 specification)
More than 50 MPa/ 7,250 psi (4JJ1 except Euro 4 specification)
More than 60 MPa/ 8,700 psi (4JK1)

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6E-50 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Scan Tool Data Definitions
This information will assist in emission or driveability
problems. The displays can be viewed while the vehicle
is being driven. Always perform the Diagnostic System
Check - Engine Controls first. The Diagnostic System
Check will confirm proper system operation.
Engine Speed
This parameter displays the rotational speed of the
crankshaft as calculated by the ECM based on inputs
from the crankshaft position (CKP) sensor or camshaft
position (CMP) sensor.
Desired Idle Speed
This parameter displays the idle speed requested by
the ECM. The ECM will change desired idle speed
based on engine coolant temperature and other inputs.
Calculate Engine Load
This parameter displays the engine load in percent
based on inputs to the ECM from various engine
sensors. The scan tool will display a lower percentage
when the engine is at idle with little or no load. The
scan tool will display a higher percentage when the
engine is running at high engine speed under a heavy
load.
Coolant Temperature
This parameter displays the temperature of the engine
coolant as calculated by the ECM using the signal from
the engine coolant temperature (ECT) sensor. The
scan tool will display a low temperature when the ECT
sensor signal voltage is high, and a high temperature
when the ECT sensor signal voltage is low.
Engine Coolant Temperature Sensor
This parameter displays the voltage signal sent to the
ECM from the engine coolant temperature (ECT)
sensor. ECT sensor is a range of value indicating a low
voltage when the temperature is high, and a high
voltage when the temperature is low.
Intake Air Temperature
This parameter displays the temperature of the intake
air as calculated by the ECM using the signal from the
intake air temperature (IAT) sensor. The scan tool will
display a low temperature when the IAT sensor signal
voltage is high, and a high temperature when the IAT
sensor signal voltage is low. Intake Air Temperature Sensor
This parameter displays the voltage signal sent to the
ECM from the intake air temperature (IAT) sensor. IAT
sensor is a range of value indicating a low voltage
when the temperature is high, and a high voltage when
the temperature is low.
Fuel Temperature
This parameter displays the temperature of the fuel as
calculated by the ECM using the signal from the fuel
temperature (FT) sensor. The scan tool will display a
low temperature when the FT sensor signal voltage is
high, and a high temperature when the FT sensor
signal voltage is low.
Fuel Temperature Sensor
This parameter displays the voltage signal sent to the
ECM from the fuel temperature (FT) sensor. FT sensor
is a range of value indicating a low voltage when the
temperature is high, and a high voltage when the
temperature is low.
MAF (Mass Air Flow)
This parameter displays the air flow into the engine as
calculated by the ECM based on the mass air flow
(MAF) sensor input. The scan tool will display a high
value at higher engine speeds, and a low value at lower
engine speed.
MAF Sensor (Mass Air Flow)
This parameter displays the voltage signal sent to the
ECM from the mass air flow (MAF) sensor. MAF sensor
is a range of value indicating a low voltage at lower
engine speed, and a high voltage at a higher engine
speeds.
Barometric Pressure
This parameter displays the barometric pressure
(BARO) as calculated by the ECM using the signal from
the BARO sensor. The scan tool will display a low
barometric pressure in high altitude area.
Barometric Pressure Sensor
This parameter displays the voltage signal sent to the
ECM from the barometric pressure (BARO) sensor.
BARO sensor is a range of value indicating a low
voltage in high altitude area, and a middle voltage in
sea level.
Immobilizer Signal Yes/ NoYes Yes
Security Wait Time Inactive/ Time
(hour: minute: second) Inactive
Inactive
Scan Tool Parameter Units Displayed Typical Data Value at Engine Idle Typical Data Value at 2000RPM

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-55
Scan Tool Output Controls
Scan Tool Output ControlDescriptions
Fuel Supply Pump Learn Resetting The purpose of this test to reset the fuel supply pump adjustment value.
Important: The fuel supply pump relearn procedure must be done when the fuel supply
pump or engine is replaced, or an ECM from another vehicle is installed. Refer to Fuel
Supply Pump Replacement.
Fuel Pressure Control The purpose of this test is for checking whether the fuel rail pressure is changing when
commanded within 30 to 80MPa (4,350 to 11,600psi) when commanded. Faulty fuel supply
pump, fuel rail pressure (FRP) regulator, pressure limiter valve or other fuel lines could be
considered if the differential fuel rail pressure is large.
Pilot Injection Control The purpose of this test is for checking whether the pilot fuel injection is operated when it is
commanded to ON/ OFF. Faulty injector(s) could be considered if engine noise does not
change when commanded OFF.
Injection Timing Control The purpose of this test is for checking whether the main injection timing is changing when
commanded Retard/ Advance within -5 to 5 °CA.
Injector Force Drive The purpose of this test is for checking whether the fuel injector is correctly operating when
commanded ON. Faulty injector(s) could be considered if it does not create a clicking noise
(solenoid operating noise), contains an interrupted noise or has abnormal noise when
commanded ON.
Cylinder Balance Test The purpose of this test is for checking whether the fuel injector is operating when
commanded ON/ OFF. Faulty injector(s) could be considered if engine does not change
speed when commanded OFF.
Intake Throttle Solenoid Control The purpose of this test is for checking whether the intake throttle valve is correctly moved
with command. Restricted valve movement by foreign materials, excessive deposits or a
faulty valve could be considered if the position difference is large.
EGR Solenoid Control The purpose of this test is for checking whether the EGR valve is correctly moved with
command. Restricted valve movement by foreign materials, excessive deposits or a faulty
valve could be considered if the position difference is large.
Swirl Control Solenoid Control The purpose of this test is for checking whether the swirl control solenoid is operating when
commanded ON. Faulty circuit(s) or a faulty solenoid could be considered if not energizing
when commanded ON.
Turbocharger Solenoid Control The purpose of this test is for checking whether the turbocharger nozzle control actuator is
correctly moved with command. Restricted actuator movement by foreign materials,
excessive deposits, misrouted vacuum hoses, a faulty solenoid or a faulty actuator could be
considered if the actuator is not moved correctly.
Glow Relay Control The purpose of this test is for checking whether the glow relay is operating when
commanded ON. Faulty circuit(s) or a faulty glow relay could be considered if not energizing
when commanded ON.
Glow Plug Lamp Control The purpose of this test is for checking whether the glow indicator lamp is operating when
commanded ON. Faulty circuit(s) or an open circuit could be considered when not operating
when commanded ON.
Malfunction Indicator Lamp (MIL) Control The purpose of this test is for checking whether the MIL is operating when commanded ON.
Faulty circuit(s) or an open circuit could be considered when not operating when
commanded ON.
Service Vehicle Soon (SVS) Lamp Control The purpose of this test is for checking whether the SVS lamp is operating when
commanded ON. Faulty circuit(s) or an open circuit could be considered when not operating
when commanded ON.
Cruise Main Lamp Control The purpose of this test is for checking whether the cruise main lamp is operating when
commanded ON. Faulty circuit(s) or an open circuit could be considered when not operating
when commanded ON.
Cruise Set Lamp Control The purpose of this test is for checking whether the cruise set lamp is operating when
commanded ON. Faulty circuit(s) or an open circuit could be considered when not operating
when commanded ON.

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6E-56 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Scan Tool Does Not Power Up
Circuit Description
The data link connector (DLC) is a standardized 16-
cavity connector. Connector design and location is
dictated by an industry wide standard, and is required
to provide the following:
• Scan tool power battery positive voltage at terminal 16.
• Scan tool power ground at terminal 4. • Common signal ground at terminal 5.
The scan tool will power up with the ignition OFF.
Some modules however, will not communicate unless
the ignition is ON.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Scan Tool Does Not Power Up
Step Action Value(s)Yes No
1 Important
: Make sure the scan tool works properly
on another vehicle before using this chart.
1. Turn OFF the ignition.
2. Inspect the Meter (+B) (10A) fuse in the cabin fuse block.
Is the Meter (+B) (10A) fuse open? —
Go to Step 2 Go to Step 3
2 Replace the Meter (+B) (10A) fuse. If the fuse
continues to open, repair the short to ground on
one of the circuits that is fed by the Meter (+B)
(10A) fuse or replace the shorted attached
component.
Did you complete the repair? —
Go to Step 7
—
31. Check each circuit at the data link connector
(DLC) (B-58) for a backed out, spread or
missing terminal.
2. Repair the terminal as necessary.
Did you find and complete the repair? —
Go to Step 7 Go to Step 4
4 Connect a test lamp between the +B circuit (pin 16
of B-58) at the DLC and a known good ground.
Does the test lamp illuminate? —
Go to Step 6 Go to Step 5
5 Repair the open in the battery voltage circuit to the
DLC.
Did you complete the repair? —
Go to Step 7
—
61. Test each ground circuit at the DLC (pins 4
and 5 of B-58) for an open circuit or high
resistance.
2. Repair the circuit(s), clean or tighten ground as necessary.
Did you find and correct the condition? —
Go to Step 7 Go to Intermittent
Conditions
7 1. Connect the scan tool to the DLC.
2. Attempt to turn ON the scan tool.
Does the scan tool ON? —
System OK Go to Step 1

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-57
Scan Tool Does Not Communicate with CAN Device
Circuit Description
The ECM, transmission control module (TCM) (AISIN
A/T only) and immobilizer control unit (ICU) all
communicate with the scan tool over the controller area
network (CAN) link. The ECM, TCM, ICU and the data
recording module (DRM) communicate with each other
over the same CAN link. If no immobilizer system is
installed, the instrument panel (IP) cluster has a CAN
terminating resistor instead of the ICU.
Diagnostic Aids
The following conditions will cause a loss of CAN serial
data communication between the TCM and ICU or
between the scan tool and any control module: • A CAN serial data circuit open
• A CAN serial data circuit shorted to ground
• A CAN serial data circuit shorted to voltage
• An internal condition within a module or connector on the CAN serial data circuit, that causes a short
to voltage or ground to the CAN serial data circuit
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Scan Tool Does Not Communicate with CAN Device
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check - Engine Controls
2 Important
: Make sure the CANdi module is not
malfunctioning. When functioning properly, the
CANdi module LED will be flashing. In the event of
a problem, the LED will be continually illuminated
or not illuminated.
1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Attempt to establish communication with the listed control modules.
•ECM
• Immobilizer Control Unit (ICU) (If so equipped)
• Transmission control module (TCM) (AISIN A/T only)
Does the scan tool communicate with any of the
listed control modules? —
Go to Step 3 Go to Step 7
3 Does the scan tool communicate with the ECM?
—
Go to Step 4 Go to Lost
Communication with
The Engine Control Module (ECM)
4 Notice:
If no AISIN automatic transmission is
installed, skip to Step 5.
Does the scan tool communicate with the TCM? —
Go to Step 5 Go to Diagnostic
System Check -
Transmission Controls
5 Notice:
If no immobilizer system is installed, skip to
Step 6.
Does the scan tool communicate with the ICU? —
Go to Step 6 Go to Diagnostic
System Check -
Immobilizer Controls
6 Test the CAN Low and High serial data circuit for an
intermittently short to ground or intermittently short
to voltage. Then, test the CAN Low and High serial
data circuit for an intermittently open (based on
which control module did not communicate) at the
connection in the circuit.
Did you find and correct the condition? —
Go to Step 19 System OK

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6E-60 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Lost Communication with The Engine Control Module (ECM)
Circuit Description
The ECM, transmission control module (TCM) (AISIN
A/T only) and immobilizer control unit (ICU) all
communicate with the scan tool over the controller area
network (CAN) link. The ECM, TCM, ICU and the data
recording module (DRM) communicate with each other
over the same CAN link. If no immobilizer system is
installed, the instrument panel (IP) cluster has a CAN
terminating resistor instead of the ICU. Schematic Reference:
Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Lost Communication with The Engine Control Module (ECM)
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 Attempt to establish communication with the ECM.
Does the scan tool communicate with the ECM? —Go to Intermittent
Conditions Go to Step 3
3 Check the ECM C-58 and E-90 connectors for poor
connections.
Did you find and correct the condition? —
Go to Step 16 Go to Step 4
4 1. Check the ECM (40A) slow blow fuse, ECM
(B) (10A) fuse and Engine (10A) fuse.
Replace and retest if open. If any fuse
continues to open, repair the short to ground
on each circuit fed by that fuse.
2. Turn OFF the ignition.
3. Disconnect the ECM C-58 harness connector.
4. Turn ON the ignition, with the engine OFF.
5. Connect a test lamp to ground and check for voltage at the ignition voltage supply circuit at
the ECM (pin 72 of C-58).
Does the test lamp illuminate? —
Go to Step 5 Go to Step 13
5 1. Turn OFF the ignition.
2. Disconnect the scan tool from the data link connector (DLC) if connected.
3. Measure the resistance across the CAN Low and High circuits by probing the DLC (pins 6
and 14 of B-58).
Is the resistance within the specified value (parallel
resistance of the 120 Ω resistor in the ECM and the
120 Ω resistor in the ICU or IP cluster should be
60 Ω)? 50 to 70
Ω
Go to Step 7 Go to Step 6
6 1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent, for poor connections and corrosion at the harness
connector of the ECM (pins 66 and 67 of C-
58).
4. Test for high resistance on each circuit.
5. Repair the connection(s) or circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 15

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-61
71. Check ECM ground for corrosion and
tightness.
2. Clean or tighten grounds as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 8
8 1. Turn OFF the ignition.
2. Reconnect the ECM harness connector if disconnected.
3. Replace the ECM main relay with the heater relay or replace with a known good relay.
4. Turn ON the ignition, with the engine OFF.
5. Attempt to establish communication with the ECM.
Does the scan tool communicate with the ECM? —
Go to Step 14 Go to Step 9
9 1. Turn OFF the ignition.
2. Remove the ECM main relay.
3. Turn ON the ignition, with the engine OFF.
4. Using a test lamp, check for both voltage supply circuits to the ECM main relay (pins 4
and 5 of X-12).
5. Repair the open circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 10
10 1. Reinstall the ECM main relay.
2. Turn the ignition ON and OFF while listening of feeling for the ECM main relay click. Wait 7
seconds between transitions.
Does the ECM main relay click when the ignition
switch is turned ON or OFF? —
Go to Step 12 Go to Step 11
11 Repair the ECM main relay ground circuit between
the ECM main relay (pin 2 of X-12) and engine
room ground terminal (C-36) for the following
conditions: •An open circuit
• High resistance or a poor connection at the
ECM main relay or ground terminal
Did you complete the repair? —
Go to Step 16
—
121. Test the battery voltage circuit between the
ECM (pin 73 of C-58) and the ECM main relay
(pin 1 of X-12) for the following conditions:
• An open circuit
• High resistance or a poor connection at ECM or ECM main relay
2. Repair the circuit(s) as necessary.
Did you find and correct the condition? —
Go to Step 16 Go to Step 15
13 Repair the open in the ignition voltage circuit to the
ECM.
Did you complete the repair? —
Go to Step 16
—
14Replace the ECM main relay.
Did you complete the replacement? —
Go to Step 16—
Step Action Value(s)Yes No

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ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-63
Engine Cranks but Does Not Run
Description
The Engine Cranks but Does Not Run diagnostic table
is an organized approach to identifying a condition that
causes an engine to not start. The diagnostic table
directs the service technician to the appropriate system
diagnosis. The diagnostic table assumes the following
conditions are met:
• The battery is completely charged and terminals are cleaned and tight.
• The engine cranking speed is normal.
• There is adequate fuel in the fuel tank.
• There is no fuel leak in the fuel line.
• There is no air in the fuel line.
• Filters (air, fuel) are clean.
• Fuse and slow blow fuse are normal. Diagnostic Aids
• If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
Test Description
The number below refers to the step number on the
Circuit/ System Testing.
5. If the fuel rail pressure (FRP) regulator low side
circuits between the ECM and the FRP regulator are
shorted to ground, FRP Regulator Feedback will be
approximately 400mA lower as compared with normal.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing Engine Cranks but Does Not Run (1of 2)
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Engine Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Engine Controls
2 1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Crank the engine for the specified amount of time.
4. Monitor the DTC Information with a scan tool.
Does the scan tool display any DTCs that failed this
ignition? 15 seconds
Go to Applicable DTC Go to Step 3
3 1. Turn OFF the ignition.
2. Wait 1 minute for the fuel pressure to bleed down from the fuel rail.
3. Turn ON the ignition, with the engine OFF. DO NOT start the engine.
4. Observe the Fuel Rail Pressure parameter with a scan tool.
Does the scan tool indicate the specified value? 0 MPa (0 psi)
Go to Step 4 Go to Step 6
4 Notice:
If the vehicle has run out of fuel, air may
be trapped in the fuel system.
1. Make sure the fuel tank have adequate fuel and the fuel quality is good (take a sample).
2. Observe the Fuel Rail Pressure parameter on the scan tool while cranking over the engine
for 5 seconds.
Does the scan tool indicate more than the specified
value during crank? 20 MPa (2,900
psi)
Go to Step 9 Go to Step 5
5 Observe the FRP Regulator Feedback parameter
on the scan tool while cranking over the engine for
5 seconds.
Does the scan tool indicate more than the specified
value during crank? 1500 mA
Go to 2 of 2 Step 1 Go to Step 8

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