6E–4 ENGINE DRIVEABILITY AND EMISSIONS
DIAGNOSTIC TROUBLE CODE (DTC) P0443 EVAPORATIVE (EVAP) EMISSION CONTROL
SYSTEM PURGE CONTROL CIRCUIT ..... 6E-191
Circuit Description ..................................... 6E-191
Diagnostic Aids .......................................... 6E-191
Diagnostic Trouble Code (DTC) P0443 EVAP Emission Control System Purge
Control Circuit .......................................... 6E-192
DIAGNOSTIC TROUBLE CODE (DTC) P0502 VEHICLE SPEED SENSOR (VSS) CIRCUIT
LOW INPUT ................................................ 6E-195
Circuit Description ..................................... 6E-195
Diagnostic Aids .......................................... 6E-195
Diagnostic Trouble Code (DTC) P0502 Vehicle Speed Sensor Circuit Low Input . 6E-196
DIAGNOSTIC TROUBLE CODE (DTC) P0562 SYSTEM VOLTAGE LOW .......................... 6E-202
Circuit Description ..................................... 6E-202
Diagnostic Aids .......................................... 6E-202
Diagnostic Trouble Code (DTC) P0562 System Voltage Low ............................................. 6E-202
DIAGNOSTIC TROUBLE CODE (DTC) P0563 SYSTEM VOLTAGE HIGH ......................... 6E-204
Circuit Description ..................................... 6E-204
Diagnostic Aids .......................................... 6E-204
Diagnostic Trouble Code (DTC) P0563 System Voltage High ............................................ 6E-204
DIAGNOSTIC TROUBLE CODE (DTC) P0601 ECM MEMORY CHECKSUM ..................... 6E-206
Circuit Description ..................................... 6E-206
Diagnostic Aids .......................................... 6E-206
Diagnostic Trouble Code (DTC) P0601 ECM Memory Checksum .................................. 6E-206
DIAGNOSTIC TROUBLE CODE (DTC) P0602 ECU PROGRAMMING ERROR ................. 6E-207
Circuit Description ..................................... 6E-207
Diagnostic Aids .......................................... 6E-207
Diagnostic Trouble Code (DTC) P0602 ECU Programming Error .................................. 6E-207
DTC P0650 MALFUNCTION INDICATOR LAMP (MIL) CONTOROL CIRCUIT MALFUNCTION 6E-208
Circuit Description ..................................... 6E-208
Diagnostic Aids .......................................... 6E-208
Diagnostic Trouble Code (DTC) P0650 Malfunction Indicator Lamp (MIL) Control
Circuit Malfunction ................................... 6E-209
DIAGNOSTIC TROUBLE CODE (DTC) P1167 FUEL SUPPLY SYSTEM RICH DURING
DECELERATION FUEL CUT OFF ............. 6E-211
Circuit Description ..................................... 6E-211
Diagnostic Aids .......................................... 6E-211
Diagnostic Trouble Code (DTC) P1167 Fuel Supply System Rich During
Deceleration Fuel Cutoff .......................... 6E-212
DIAGNOSTIC TROUBLE CODE (DTC) P1171 FUEL SUPPLY SYSTEM LEAN DURING
POWER ENRICHMENT ............................. 6E-214
Circuit Description ...................................... 6E-214
Diagnostic Aids .......................................... 6E-215
Diagnostic Trouble Code (DTC) P1171 Fuel Supply System Lean During Power
Enrichment .............................................. 6E-215
DIAGNOSTIC TROUBLE CODE (DTC) P1625 ECM SYSTEM RESET ............................... 6E-217
Circuit Description ...................................... 6E-217
Diagnostic Aids .......................................... 6E-217
Diagnostic Trouble Code (DTC) P1625 ECM System Reset .......................................... 6E-217
DIAGNOSTIC TROUBLE CODE (DTC) P1626 IMMOBILIZER NO SIGNAL ........................ 6E-218
Circuit Description ...................................... 6E-218
Diagnostic Aids .......................................... 6E-218
Diagnostic Trouble Code (DTC) P1626 Immobilizer No Signal .............................. 6E-219
DIAGNOSTIC TROUBLE CODE (DTC) P1631 IMMOBILIZER WRONG SIGNAL ............... 6E-222
Circuit Description ...................................... 6E-222
Diagnostic Aids .......................................... 6E-222
Diagnostic Trouble Code (DTC) P1631 Immobilizer Wrong Signal ........................ 6E-223
DIAGNOSTIC TROUBLE CODE (DTC) P1648 WRONG SECURITY CODE ENTERED .. 6E-224
Circuit Description ...................................... 6E-224
Diagnostic Aids .......................................... 6E-224
Diagnostic Trouble Code (DTC) P1648 Wrong Security Code Entered ............................ 6E-225
DIAGNOSTIC TROUBLE CODE (DTC) P1649 IMMOBILIZER FUNCTION NOT
PROGRAMMED ......................................... 6E-226
Circuit Description ...................................... 6E-226
Diagnostic Aids .......................................... 6E-226
Diagnostic Trouble Code (DTC) P1649 Immobilizer Function Not Programmed ... 6E-227
DIAGNOSTIC TROUBLE CODE (DTC) P1693 TACHOMETER OUTPUT LOW VOLTAGE 6E-228
Circuit Description ...................................... 6E-228
Diagnostic Aids .......................................... 6E-228
Diagnostic Trouble Code (DTC) P1693 Tachometer Output Low Voltage ............. 6E-229
SYMPTOM DIAGNOSIS ............................... 6E-232
PRELIMINARY CHECKS ............................. 6E-232
VISUAL/PHYSICAL CHECK ......................... 6E-232
INTERMITTENT ........................................... 6E-232
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ISUZU KB P190 2007
6E–6 ENGINE DRIVEABILITY AND EMISSIONS
ABBREVIATIONS CHARTS
AbbreviationsAppellation
A/C Air Conditioner
A/T Automatic Transmission
ACC Accessory
BLK Black
BLU Blue
BRN Brown
CEL Check Engine Lamp
CKP Crankshaft Position
DLC Data Link Connector
DTC Diagnostic Trouble Code
DVM Digital Volt Meter
ECM Engine Control Module
ECT Engine Coolant Temperature
EEPROM Electrically Erasable & Programmable Read Only Memory
EVAP Evaporative Emission
EVRV Electric Vacuum Regulating Valve
EXH Exhaust
FT Fuel Temperature
GND Ground
GRY Gray
HOS2 Heated Oxygen Sensor
IAC Idel Air Control
IAT Intake Air Temperature
IG Ignition
ITP Intake Throttle Position
KS Knock Sensor
M/T Manual Transmission
MAP Manifold Absolute Pressure
MIL Malfunction Indicator Lamp
OBD On-Board Diagnostic
ORN Orange
OT Oil Temperature
PNK Pink
RED Red
SW Switch
TB Throttle Body
TEMP Temperature
TP Throttle Position
VCC Voltage Constant Control
VSS Vehicle Speed Sensor
WHT White
YEL Yellow
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ISUZU KB P190 2007
6E–48 ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR ECM AND
SENSORS
Engine Control Module (ECM)
The engine control module (ECM) is located on the
intake manifold. The ECM controls the following.
• Fuel metering system
• Ignition timing
• On-board diagnostics for electrical functions.
The ECM constantly observes the information from vari-
ous sensors. The ECM controls the systems that affect
vehicle performance. And it performs the diagnostic
function of the system.
The function can recognize operational problems, and
warn to the driver through the check engine lamp, and
store diagnostic trouble code (DTC). DTCs identify the
problem areas to aid the technician in marking repairs.
The input / output devices in the ECM include analog to
digital converts, signal buffers, counters and drivers.
The ECM controls most components with electronic
switches which complete a ground circuit when turned
on.
Inputs (Operating condition read):
• Battery voltage
• Electrical ignition
• Exhaust oxygen content
• Intake manifold pressure
• Intake air temperature
• Engine coolant temperature
• Crankshaft position • Knock signal
• Throttle position
• Vehicle speed
• Power steering pressure
• Air conditioning request on or off
Outputs (Systems controlled):
• Ignition control
• Fuel control
• Idle air control
• Fuel pump
• EVAP canister purge
• Air conditioning
• Diagnostics functions
Manifold Absolute Pressure (MAP) Sensor
The MAP sensor is a strain gage. A pressure strains the
resistance on the silicon base. At that time the
resistance value changes. And it changes voltage. In
other words it measures a pressure value. It is installed
to the intake manifold. Output voltage of the MAP
sensor is low as pressure is low.
(1) J1 Port
(2) J2 Port
12
C harac t eris t ic of MAP Sens or -R ef erenc e-
0
0.5 1
1.5 2
2.5
3
3.5 4
4.5 5
15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 Manifold Abs olute Press ure (KPa) (T ec h2 Reading)
Output Voltage (V)
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ISUZU KB P190 2007
6E–54 ENGINE DRIVEABILITY AND EMISSIONS
GENERAL DESCRIPTION FOR ELECTRIC
IGNITION SYSTEM
The engine use two ignition coils, one per two cylinders.
A two wire connector provides a battery voltage primary
supply through the ignition fuse.
The ignition control spark timing is the ECM’s method of
controlling the spark advance and the ignition dwell.
The ignition control spark advance and the ignition dwell
are calculated by the ECM using the following inputs.
• Engine speed
• Crankshaft position (CKP) sensor
• Engine coolant temperature (ECT) sensor
• Throttle position sensor
• Vehicle speed sensor
• ECM and ignition system supply voltage
Ignition coil works to generate only the secondary
voltage be receiving the primary voltage from ECM.
The primary voltage is generated at the coil driver
located in the ECM. The coil driver generate the primary
voltage based on the crankshaft position signal. In
accordance with the crankshaft position signal, ignition
coil driver determines the adequate ignition timing and
also cylinder number to ignite.
Ignition timing is determined the coolant temperature,
intake air temperature, engine speed, engine load,
knock sensor signal, etc.
Spark Plug
Although worn or dirty spark plugs may give satisfactory
operation at idling speed, they frequently fail at higher
engine speeds. Faulty spark plugs may cause poor fuel
economy, power loss, loss of speed, hard starting and
generally poor engine performance. Follow the
scheduled maintenance service recommendations to
ensure satisfactory spark plug performance. Refer to
Maintenance and Lubrication .
Normal spark plug operation will result in brown to
grayish-tan deposits appearing on the insulator portion
of the spark plug. A small amount of red-brown, yellow,
and white powdery material may also be present on the
insulator tip around the center electrode. These
deposits are normal combustion by-products of fuels
and lubricating oils with additives. Some electrode wear
will also occur. Engines which are not running properly
are often referred to as “misfiring.” This means the
ignition spark is not igniting the air/fuel mixture at the
proper time. While other ignition and fuel system causes
must also be considered, possible causes include
ignition system conditions which allow the spark voltage
to reach ground in some other manner than by jumping
across the air gap at the tip of the spark plug, leaving
the air/fuel mixture unburned. Misfiring may also occur
when the tip of the spark plug becomes overheated and
ignites the mixture before the spark jumps. This is
referred to as “pre-ignition.”
Spark plugs may also misfire due to fouling, excessive
gap, or a cracked or broken insulator. If misfiring occurs before the recommended replacement interval, locate
and correct the cause.
Carbon fouling of the spark plug is indicated by dry,
black carbon (soot) deposits on the portion of the spark
plug in the cylinder. Excessive idling and slow speeds
under light engine loads can keep the spark plug
temperatures so low that these deposits are not burned
off. Very rich fuel mixtures or poor ignition system output
may also be the cause. Refer to DTC P1167.
Oil fouling of the spark plug is indicated by wet oily
deposits on the portion of the spark plug in the cylinder,
usually with little electrode wear. This may be caused by
oil during break-in of new or newly overhauled engines.
Deposit fouling of the spark plug occurs when the
normal red-brown, yellow or white deposits of
combustion by-products become sufficient to cause
misfiring. In some cases, these deposits may melt and
form a shiny glaze on the insulator around the center
electrode. If the fouling is found in only one or two
cylinders, valve stem clearances or intake valve seals
may be allowing excess lubricating oil to enter the
cylinder, particularly if the deposits are heavier on the
side of the spark plug facing the intake valve.
Excessive gap means that the air space between the
center and the side electrodes at the bottom of the
spark plug is too wide for consistent firing. This may be
due to improper gap adjustment or to excessive wear of
the electrode during use. A check of the gap size and
comparison to the gap specified for the vehicle in
Maintenance and Lubrication will tell if the gap is too
wide. A spark plug gap that is too small may cause an
unstable idle condition. Excessive gap wear can be an
indication of continuous operation at high speeds or
with engine loads, causing the spark to run too hot.
Another possible cause is an excessively lean fuel
mixture.
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6E–62 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Thought Process
As you follow a diagnostic plan, every box on the
Strategy Based Diagnostics chart requires you to use
the diagnostic thought process. This method of thinking
optimizes your diagnosis in the following ways:
• Improves your understanding and definition of the customer complaint
• Saves time by avoiding testing and/or replacing good parts
• Allows you to look at the problem from different perspectives
• Guides you to determine what level of understanding about system operation is needed:
– Owner’s manual level
– Service manual level
– In-depth (engineering) level – Owner’s manual level
– Service manual level
– In-depth (engineering) level
1. Verify the Complaint
What you should do
To verify the customer complaint, you need to know the
correct (normal) operating behavior of the system and
verify that the customer complaint is a valid failure of the
system.
The following information will help you verify the
complaint:
• WHAT the vehicle model/options are
• WHAT aftermarket and dealer-installed accessories exist
• WHAT related system(s) operate properly
• WHEN the problem occurs
• WHERE the problem occurs
• HOW the problem occurs
• HOW LONG the condition has existed (and if the system ever worked correctly)
• HOW OFTEN the problem occurs
• Whether the severity of the problem has increased, decreased or stayed the same
What resources you should use
Whenever possible, you should use the following
resources to assist you in verifying the complaint:
• Service manual Theory or Circuit Description sections
• Service manual “System Performance Check”
• Owner manual operational description
• Technician experience
• Identical vehicle for comparison • Circuit testing tools
• Vehicle road tests
• Complaint check sheet
• Contact with the customer
2. Perform Preliminary Checks
NOTE: An estimated 10 percent of successful vehicle
repairs are diagnosed with this step!
What you should do
You perform preliminary checks for several reasons:
• To detect if the cause of the complaint is VISUALLY OBVIOUS
• To identify parts of the system that work correctly
• To accumulate enough data to correctly and accurately search for a ISUZU Service Bulletin on
ISUZU Web site.
The initial checks may vary depending on the
complexity of the system and may include the following
actions:
• Operate the suspect system
• Make a visual inspection of harness routing and accessible/visible power and ground circuits
• Check for blown fuses
• Make a visual inspection for separated connectors
• Make a visual inspection of connectors (includes checking terminals for damage and tightness)
• Check for any DTCs stored by the on-board computers
• Sense unusual noises, smells, vibrations or movements
• Investigate the vehicle service history (call other dealerships, if appropriate)
What resources you should use
Whenever appropriate, you should use the following
resources for assistance in performing preliminary
checks:
• Tech II or other technical equipment for viewing DTCs
• Service manual information: – Component locations
– Harness routing
– Wiring schematics
– Procedures for viewing DTCs
• Dealership service history file
• Vehicle road test
• Identical vehicle or system for comparison
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ISUZU KB P190 2007
ENGINE DRIVEABILITY AND EMISSIONS 6E–63
3. Check Bulletins and Troubleshooting Hints
NOTE: As estimated 30 percent of successful vehicle
repairs are diagnosed with this step!
What you should do
You should have enough information gained from
preliminary checks to accurately search for a bulletin
and other related service information. Some service
manual sections provide troubleshooting hints that
match symptoms with specific complaints.
What resources you should use
You should use the following resources for assistance in
checking for bulletins and troubleshooting hints:
• Printed bulletins
• Access ISUZU Bulletin Web site.
• Videotapes
• Service manual
4. Perform Service Manual Diagnostic Checks
What you should do
The “System Checks” in most service manual sections
and in most cells of section 8A (electrical) provide you
with:
• A systematic approach to narrowing down the possible causes of a system fault
• Direction to specific diagnostic procedures in the service manual
• Assistance to identify what systems work correctly
What resources you should use
Whenever possible, you should use the following
resources to perform service manual checks:
• Service manual
• Technical equipment (for viewing DTCs and analyzing data)
• Digital multimeter and circuit testing tools
• Other tools as needed
5a and 5b. Perform Service Manual Diagnostic Procedures
NOTE: An estimated 40 percent of successful vehicle
repairs are diagnosed with these steps!
What you should do
When directed by service manual diagnostic checks,
you must then carefully and accurately perform the
steps of diagnostic procedures to locate the fault related to the customer complaint.
What resources you should use
Whenever appropriate, you should use the following
resources to perform service manual diagnostic
procedures:
• Service manual
• Technical equipment (for analyzing diagnostic data)
• Digital multimeter and circuit testing tools
• Essential and special tools
5c. Technician Self Diagnoses
When there is no DTC stored and no matching
symptom for the condition identified in the service
manual, you must begin with a thorough understanding
of how the system(s) operates. Efficient use of the
service manual combined with you experience and a
good process of elimination will result in accurate
diagnosis of the condition.
What you should do
Step 1: Identify and understand the suspect
circuit(s)
Having completed steps 1 through 4 of the Strategy
Based Diagnostics chart, you should have enough
information to identify the system(s) or sub-system(s)
involved. Using the service manual, you should
determine and investigate the following circuit
characteristics:
• Electrical: – How is the circuit powered (power distributioncharts and/or fuse block details)?
– How is the circuit grounded (ground distribution charts)?
– How is the circuit controlled or sensed (theory of operation):
– If it is a switched circuit, is it normally open or normally closed?
– Is the power switched or is the ground switched?
– Is it a variable resistance circuit (ECT sensor or TP sensor, for example)?
– Is it a signal generating device (MAF sensor of VSS, for example)?
– Does it rely on some mechanical/vacuum device to operate?
•Physical:
– Where are the circuit components (componentlocators and wire harness routing diagrams):
– Are there areas where wires could be chafed or pinched (brackets or frames)?
– Are there areas subjected to extreme temperatures?
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ISUZU KB P190 2007
6E–68 ENGINE DRIVEABILITY AND EMISSIONS
On-Board Diagnostic (OBD)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which
is a pass or fail reported to the diagnostic executive.
When a diagnostic test reports a pass result, the
diagnostic executive records the following data:
• The diagnostic test has been completed since the last ignition cycle.
• The diagnostic test has passed during the current ignition cycle.
• The fault identified by the diagnostic test is not currently active.
When a diagnostic test reports a fail result, the
diagnostic executive records the following data:
• The diagnostic test has been completed since the last ignition cycle.
• The fault identified by the diagnostic test is currently active.
• The fault has been active during this ignition cycle.
• The operating conditions at the time of the failure.
The Diagnostic Executive
The Diagnostic Executive is a unique segment of
software which is designed to coordinate and prioritize
the diagnostic procedures as well as define the protocol
for recording and displaying their results. The main
responsibilities of the Diagnostic Executive are listed as
follows:
• Commanding the check engine lamp on and off
• DTC logging and clearing
• Current status information on each diagnostic
Diagnostic Information
The diagnostic charts and functional checks are
designed to locate a faulty circuit or component through
a process of logical decisions. The charts are prepared
with the requirement that the vehicle functioned
correctly at the time of assembly and that there are not
multiple faults present.
There is a continuous self-diagnosis on certain control
functions. This diagnostic capability is complemented
by the diagnostic procedures contained in this manual.
The language of communicating the source of the
malfunction is a system of diagnostic trouble codes.
When a malfunction is detected by the control module, a
diagnostic trouble code is set and the check engine
lamp is illuminated.
Check Engine Lamp
The check engine lamp looks the same as the check
engine lamp you are already familiar with, the “Check
Engine” lamp.
Basically, the check engine lamp is turned on when the
ECM detects a DTC that will impact the vehicle
emissions.
• When the check engine lamp remains “ON” while the engine is running, or when a malfunction is suspected due to a driveability or emissions problem,
a Powertrain On-Board Diagnostic (OBD) System
Check must be performed. The procedures for these
checks are given in On-Board Diagnostic (OBD)
System Check. These checks will expose faults
which may not be detected if other diagnostics are
performed first.
Data Link Connector (DLC)
The provision for communication with the contorl
module is the Data Link Connector (DLC). It is located
behind the lower front instrument panel. The DLC is
used to connect to a Tech 2. Some common uses of the
Tech 2 are listed below:
• Identifying stored Diagnostic Trouble Codes (DTCs).
• Clearing DTCs.
• Reading serial data.
Verifying Vehicle Repair
Verification of vehicle repair will be more
comprehensive for vehicles with OBD system
diagnostic. Following a repair, the technician should
perform the following steps:
1. Review and record the Fail Records for the DTC which has been diagnosed.
2. Clear DTC(s).
3. Operate the vehicle within conditions noted in the Fail Records.
4. Monitor the DTC status information for the specific DTC which has been diagnosed until the diagnostic
test associated with that DTC runs.
Following these steps is very important in verifying
repairs on OBD systems. Failure to follow these steps
could result in unnecessary repairs.
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ENGINE DRIVEABILITY AND EMISSIONS 6E–69
Reading Diagnostic Trouble Codes Using a
Te c h 2
The procedure for reading diagnostic trouble code(s) is
to used a diagnostic Tech 2. When reading DTC(s),
follow instructions supplied by Tech 2 manufacturer.
Clearing Diagnostic Trouble Codes
To clear Diagnostic Trouble Codes (DTCs), use the
Tech 2 “clear DTCs” or “clear information” function.
When clearing DTCs follow instructions supplied by the
Tech 2 manufacturer.
Diagnosis With Tech 2
If no codes are set:
•Refer to F1: Data Display and identify the electrical
faults that are not indicated by trouble code.
• Refer to “SYMPTOM DIAGNOSIS ”.
If codes are set: 1. Record all trouble codes displayed by Tech 2 and check id the codes are intermittent.
2. Clear the codes.
3. Drive the vehicle for a test to reproduce the faulty status.
4. Check trouble codes again using the Tech 2.
5. If no codes is displayed by test driving, the fault is intermittent. In this case, refer to “DIAGNOSIS
AIDS”.
6. If a code is present, refer to DTC Chart for diagnosis.
7. Check trouble codes again using the Tech 2.
Tech 2 CONNECTION
Tech 2 scan tool is used to electrically diagnose the
automatic transmission system and to check the
system. The Tech 2 enhances the diagnosis efficiency
though all the troubleshooting can be done without the
Te c h 2 . 1. Configuration of Tech 2
• Tech 2 scan tool kit (No. 7000086), Tech 2 scan tool (No. 7000057) and DLC cable (No.
3000095).
• SAE 16/19 adapter (No. 3000098) (3), RS232 loop back connector (No. 3000112) (2) and
PCMCIA card (No. 3000117) (1).
2. Tech 2 Connection
• Check the key switch is turn OFF.
• Insert the PCMCIA card (1) into the Tech 2 (5).
• Connect the SAE 16/19 adapter (3) to the DLC cable (4).
• Connect the DLC cable (4) to the Tech 2 (5).
• Connect the SAE 16/19 adapter (3) to the data link connector of the vehicle.
• Turn the key switch of the vehicle ON and press the “PWR” key of the Tech 2.
• Check the display of the Tech 2.
NOTE: Be sure to check that the power is not supplied
to the Tech 2 when attaching or removing the PCMCIA
card.
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