2007 ISUZU KB P190 air condition

ENGINE DRIVEABILITY AND EMISSIONS 6E–229
Diagnostic Trouble Code (DTC) P1693 Tachometer Output Low Voltage
StepAction Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check” performed?
—Go to Step 2Go to
On Board
Diagnostic
(OBD) System Check
2 1. Connect the Tech 2. 2. Review and record the failure information.
3. Select “F0: Read DTC Infor By Priority” in “F0: Diagnostic Trouble Code”.
Is the DTC P1693 stored as “Present Failure”? — Go to Step 3Refer to
Diagnostic Aids and Go to Step
3
3 1. Using the Tech2, ignition “On” and engine “Off”. 2. Select “Clear DTC Information” with the Tech2 andclear the DTC information.
3. Operate the vehicle and monitor the “F5: Failed This Ignition” in “F2: DTC Information”.
Was the DTC P1693 stored in this ignition cycle? — Go to Step 4Refer to
Diagnostic Aids and Go to Step
4
4 Check for poor/faulty connection at the ECM or meter connector. If a poor/faulty connection is found, repair
the faulty terminal.
Was the problem found?
— Verify repair Go to Step 5
5 If a oscilloscope is available, monitor the Tachometer output signal. Does the oscilloscope indicate correct
wave form?
—Go to Step 10Not available:
Go to Step 6
Fixed at low: Go to Step 6
Fixed at High: Go to Step 7
25
C-56(J2) B-24
11
Crankshaft Position (CKP) Sensor & Tacho Output Signal
Reference Wave Form





CH1
0V





CH2
0V




Measurement Terminal: CH1: J1-21(+) / CH2: J2-25(+) GND(-)
Measurem ent Scale: CH1: 2V/div / CH2: 10V/div 5m s/div
Measurement Condition: Approxim ately 2000rpm

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E–232 ENGINE DRIVEABILITY AND EMISSIONS
SYMPTOM DIAGNOSIS
PRELIMINARY CHECKS
Before using this section, perform the “On-Board
Diagnostic (OBD) System Check” and verify all of the
following items:
• The engine control module (ECM) and malfunction indicator lamp (MIL = Check Engine Lamp) are
operating correctly.
• There are no Diagnostic Trouble Code(s) stored.
• Tech 2 data is within normal operating range. Refer to Typical Scan Data Values.
• Verify the customer complaint and locate the correct symptom in the table of contents. Perform the
procedure included in the symptom chart.
VISUAL/PHYSICAL CHECK
Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time. This check should include the following items:
• ECM grounds for cleanliness, tightness and proper location.
• Vacuum hoses for splits, kinks, and proper connection, shown on the “Emission Control System
Schematics”. Check thoroughly for any type of leak or
restriction.
• Air intake ducts for collapsed or damaged areas.
• Air leaks at throttle body mounting area, manifold absolute pressure (MAP) sensor and intake manifold
sealing surfaces.
• Ignition wires for cracking, harness, and carbon tracking.
• Wiring for proper connections, pinches and cuts.
INTERMITTENT
Important: An intermittent problem may or may not turn
on the malfunction indicator lamp (MIL) or store a
Diagnostic Trouble Code. Do NOT use the Diagnostic
Trouble Code (DTC) charts for intermittent problems.
The fault must be present to locate the problem.
Most intermittent problems are cased by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions.
• Poor mating of the connector halves or a terminal not fully seated in the connector (backed out).
• Improperly formed or damaged terminal.
• All connector terminals in the problem circuit should be carefully checked for proper contact tension.
• Poor terminal-to-wire connection. This requires removing the terminal form the connector body to
check.
• Ignition coils shorted to ground and arcing at ignition wires or plugs. • MIL (Check Engine Lamp) wire to ECM shorted to
ground.
• Poor ECM grounds. Refer to the ECM wiring diagrams.
Road test the vehicle with a Digital Multimeter
connected to a suspected circuit. An abnormal voltage
when the malfunction occurs is a good indication that
there is a fault in the circuit being monitored.
Using Tech 2 to help detect intermittent conditions. The
Tech 2 has several features that can be used to located
an intermittent condition.
An intermittent MIL (Check Engine Lamp) with no stored
Diagnostic Trouble Code may be caused by the
following:
• Ignition coil shorted to ground and arcing at ignition wires or plugs.
• MIL (Check Engine Lamp) wire to ECM short to ground.
• Poor ECM grounds. Refer to the ECM wiring diagrams.
Check for improper installation of electrical options such
as light, cellular phones, etc. Check all wires from ECM
to the ignition control module for poor connections.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in Electrical Diagnosis).
If problem has not been found, refer to ECM connector
symptom tables.
• Check the “Broadcast Code” of the ECM, and compare it with the latest Isuzu service bulletins and/
or Isuzu EEPROM reprogramming equipment to
determine if an update to the ECM’s reprogrammable
memory has been released.
To check the “Broadcast Code”, connect the Tech 2,
then look for “ID info.” then select “Broadcast Code”.
This should display a 4 character code, such as “XBYA”
(example only).
This identifies the contents of the reprogrammable
software and calibration contained in the ECM.
If the “Broadcast Code” is not the most current
available, it is advisable to reprogram the ECM’s
EEPROM memory, which may either help identify a
hard-to find problem or may fix the problem.
The Service Programming System (SPS) will not allow
incorrect software programming or incorrect calibration
changes.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–233
ENGINE CRANKS BUT WILL NOT RUN
DEFINITIONS: Engine cranks, but will not run. (The engine never start.)
NOTE: The replacement ECM must be programmed. Refer to section of the Service Programming System (SPS) in
this manual. Following ECM programming, the immobilizer system (if equipped) must be linked to the ECM.
Refer to section 11 “Immobilizer System-ECM replacement” for the ECM/Immobilizer linking procedure.
NOTE: The vehicle with immobilizer system, this system may be activated. Check the immobilizer system diagosis.
Step Action Value(s) Yes No
1 Was the “ On-Board Diagnostic (OBD) System Check ”
performed? — Go to Step 2Go to
OBD
System Check
2 1. Perform a bulletin search. 2. If a bulletin that addresses the symptom is found,correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3
3 Was a visually/physical check performed? —Go to Step 4Go to
Visual /
physical Check.
4 Check the “Ignition coil” fuse (15A) and “ECM” fuse (15A).
Was a fuse blown? — Verify repair Go to Step 5
5 1. Ignition ON 2. Use a DVM to verify that battery voltage at theignition coil fuse, and the ECM fuse.
Was battery voltage presented at the fuses? — Go to Step 6Verify & repair
6 1. Visually/physically inspect for the following conditions:
• Restriction of air intake system. Check for a restricted air filter element, or foreign objects
blocking the air intake system.
• Check for objects blocking the IAC passage or throttle bore, excessive deposits in the throttle
bore and on the throttle plate.
• Check for a condition that causes a large vacuum leak, such as an incorrectly installed or
faulty crankcase ventilation hose/brake booster
hose.
Was a problem found? — Verify repair Go to Step 7
7 1. Using a Tech 2, display the IAC value. 2. Check for a faulty, plugged, or sticking IACoperation.
Was the problem found? — Verify repair Go to Step 8
8 1. Using a Tech 2, display the MAP sensor value. 2. Check for a faulty, plugged, or incorrectly installedMAP sensor.
Was the problem found? — Verify repair Go to Step 9
9 If oscilloscope is available, check the wave form of the CKP signal.
Was the correct wave form found? — Go to Step 12Go to Step 10
10 Check the CKP sensor wire for open or short circuit. Was a problem found? — Verify repair Go to Step 11
11 Replace CKP sensor. Is there still problem? —Replace pulsar
ring. Verify repair

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E–234 ENGINE DRIVEABILITY AND EMISSIONS
12 Visually/physically inspect the secondary ignitionwires. Check for the following conditions:
• Verify that all ignition wire resistance are less than the specified value.
• Verify that ignition wires are correctly routed to eliminate cross-fitting.
• Verify that ignition wires are not arcing to ground. Spraying the secondary ignition wires with a light
mist of water may help locate an intermittent
problem.
Was a problem found? #1 cyl. 4.4k
Ω
#2 cyl. 3.6k Ω
#3 cyl. 3.1k Ω
#4 cyl. 2.8k ΩVerify repair Go to Step 13
13 1. Disconnect the spark plug high tension cable from No.1 spark plug.
2. Install a spark tester at the end of the disconnected ignition coil.
3. Clip the spark tester to a good ground.
4. Observe the spark tester while the engine is cranking.
Was a crisp blue spark observed? (Only one or two
sparks followed by no result is considered the same
as “No Spark”.) — Go to Step 21Go to Step 14
14 1. Disconnect the ignition coil harness connector. 2. Check for an open or short circuit between theignition coil and the ECM.
Was a problem found? — Verify repair Go to Step 15
15 1. Ignition “On”. 2. Using a Digital Voltmeter (DVM) check the ignitionwire coil at the ignition coil harness connector.
Was the voltage equal to the specified value? Battery
voltage Go to Step 16Verify repair
16 1. Ignition “Off”. 2. With DVM, check for an open in the ground wire atthe ignition coil harness connector.
Was the ground wire OK? — Go to Step 17Verify repair
17 Replace the ignition coil, verify the repair. Attempt to start the engine.
Is there still a problem? — Go to Step 18Verify repair
18 Use an ohmmeter to check the ignition coil primary winding resistance.
Was the primary winding resistance approximately
equal to the specified value? 0.8-18kΩGo to Step 19 Go to Step 20
19 Use an ohmmeter to check the ignition coil secondary winding resistance.
Was the primary winding resistance hear around the
to the specified value? 2.5kΩ Go to Step 21 Go to Step 20
20 Replace the ignition coil. — Verify repair —
21 1. Remove the spark plugs from all cylinders. 2. Visually inspect the spark plug electrodes.
3. Replace any spark plugs with loose or missing electrodes or cracked insulators.
Did your inspection reveal any spark plugs exhibiting
excessive fouling? —Correct the
fouling
condition Go to Step 22
Step
Action Value(s) Yes No

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E–236 ENGINE DRIVEABILITY AND EMISSIONS
HARD START SYMPTOM
DEFINITIONS: Engine cranks, but does not start for a long time. Does eventually start, of may start and then
immediately stall.
Step Action Value(s) Yes No
1 Was the “ On-Board Diagnostic (OBD) System Check ”
performed? — Go to Step 2Go to
OBD
System Check
2 1. Perform a bulletin search. 2. If a bulletin that addresses the symptom is found,correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3
3 Was a visually/physical check performed? —Go to Step 4Go to
Visual /
physical Check.
4 1. Visually/physically inspect for the following conditions:
• Restriction of air intake system. Check for a restricted air filter element, or foreign objects
blocking the air intake system
• Check for objects blocking the IAC passage or throttle bore, excessive deposits in the throttle
bore and on the throttle plate
• Check for a condition that causes a large vacuum leak, such as an incorrectly installed or
faulty crankcase ventilation hose/brake booster
hose.
Was a problem found? — Verify repair Go to Step 5
5 1. Using a Tech 2, display the IAC value. 2. Check for a faulty, plugged, or sticking IACoperation.
Was the problem found? — Verify repair Go to Step 6
6 Check engine coolant temperature (ECT) sensor for shift in value.
1. After 8 hours with hood up and the engine not running, connect the Tech 2.
2. Ignition On, engine not running.
3. Using Tech 2, compare Engine Coolant Temperature to Intake Air Temperature.
Are ECT and IAT within the specified value of each
other? ± 5°C Go to Step 8Go to Step 7

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–237
7 1. Using a Tech 2, display the engine coolanttemperature and note the value.
2. Check the resistance of the engine coolant temperature sensor.
Is the actual resistance near the resistance value in
the chart for the temperature that was noted?
—Go to Step 8Replace the
ECT sensor. Verify repair
8 1. Using a Tech 2, display the MAP sensor value in comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed MAP sensor.
Was the problem found? — Verify repair Go to Step 9
9 Visually/physically inspect all spark plug high-tension cables. Check for the following conditions:
• Verify that the resistance of all spark plug high- tension cables are less than the specified value.
• Verify that the all spark plug high-tension cables are correctly fitted to eliminate cross-fitting.
• Verify that the all spark plug high-tension cables are not arcing to ground.
Spraying the spark plug high-tension cables with a
light mist of water may help locate an intermittent
problem.
Was a problem found? #1 cyl. 4.4k
Ω
#2 cyl. 3.6k Ω
#3 cyl. 3.1k Ω
#4 cyl. 2.8k ΩVerify repair Go to Step 10
10 Check for proper ignition voltage output with a spark tester.
Was the problem found? — Verify repair Go to Step 11
11 1. Remove the spark plugs and check for gas or oil fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must be determined before replacing the spark plugs.
Was a problem found? — Verify repair Go to Step 12
12 Check for a loose ignition control module ground. Was a problem found? — Verify repair Go to Step 13
13 1. Check the ignition coil secondary resistance. 2. Replace the coil if it is greater than the specifiedresistance.
Did the coil require replacement? 2.5kΩ Verify repair Go to Step 14
Step
Action Value(s) Yes No
Temperature (°C) Resistance (Ω) (Approximately)
-20 26740
0 9120
20 3500
40 1464
60 664
80 333
100 175
120 102

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–239
ROUGH, UNSTABLE, OR INCORRECT IDLE, STALLING SYMPTOM
DEFINITIONS: Engine runs unevenly at idle. If severe,
the engine or vehicle may shake. Engine idle speed
may vary in RPM. Either condition may be severe
enough to stall the engine.
Step Action Value(s) Yes No
1 Was the “ On-Board Diagnostic (OBD) System Check ”
performed? — Go to Step 2Go to
OBD
System Check
2 1. Perform a bulletin search. 2. If a bulletin that addresses the symptom is found,correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3
3 Was a visual/physical check performed? —Go to Step 4Go to
Visual /
physical Check.
4 1. Check for faulty, plugged or incorrectly installed PCV valve.
2. Verify that the PCV system is not plugged.
Was a problem found? — Verify repair Go to Step 5
5 1. Check for incorrect idle speed. Ensure that the following conditions are present.
• Engine fully warm
• Accessories are “Off”
2. Using a Tech 2, monitor IAC position.
Is the IAC position within the specified values? 20-30 Steps Go to Step 7Go to Step 6
6 1. Visually/physically inspect for the following conditions:
• Restriction of the air intake system. Check for a restricted air filter element, or foreign objects
blocking the air intake system.
• Check for objects blocking the IAC passage or throttle bore, excessive deposits in the throttle
bore and on the throttle plate.
• Check for a condition that causes a large vacuum leak, such as an incorrectly installed or
faulty crankcase ventilation hose/brake booster
hose.
Was a problem found? — Verify repair Go to Step 7

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

6E–242 ENGINE DRIVEABILITY AND EMISSIONS
SURGES AND/OR CHUGS SYMPTOM
DEFINITIONS: See the illustration below. Feels like the
vehicle speeds up and slows down with no charge in the
accelerator pedal.
Step Action Value(s) Yes No
1 Was the “ On-Board Diagnostic (OBD) System Check ”
performed? — Go to Step 2Go to
OBD
System Check
2 1. Perform a bulletin search. 2. If a bulletin that addresses the symptom is found,correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3
3 Was a visual/physical check performed? —Go to Step 4Go to
Visual /
physical Check.
4 Be sure that the driver understands A/C compressor operation as explained in the owner’s manual. Inform
the customer how the A/C clutch operate.
Is the customer experiencing a normal condition? — System OK Go to Step 5
5 1. Using a Tech 2, display the MAP sensor value in comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed MAP sensor.
Was the problem found? — Verify repair Go to Step 6
6 Observe the throttle position display on the Tech 2 while slowly increasing throttle pedal.
Is the throttle position at the specified value and
steady in any position?
—Go to Step 7Refer to
Diagnostic
Trouble Code P0123 for further
diagnosis
7 Check the knock sensor wire, shield wire, or installation condition.
Was a problem found? — Verify repair Go to Step 8
8 Run Engine. Check the fuel control Heated Oxygen Sensor
(HO2S). When monitored on the Tech 2, the HO2S
should respond quickly to different throttle positions. If
it doesn’t check for silicon or other contaminates from
fuel or use of improper sealant. The sensors may
have a white powdery coating. Silicon contamination
sends a rich exhaust signal which causes the ECM to
command an excessively lean air/fuel mixture.
Was a problem found? — Verify repair Go to Step 9

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007