Isuzu KB P190. Service manual - part 604

6E–246

ENGINE DRIVEABILITY AND EMISSIONS

10

Monitor “B1S1 (Bank 1 Sensor 1) Status” on the Tech
2.
Is the “B1S1 (Bank 1 Sensor 1) Status” in the rich
condition?

—

Go to Step 11

Go to Step 12

11

Check items that can cause the engine to run rich.
Refer to DTC P1167 “Fuel Supply System Rich During
Deceleration Fuel Cut Off”.
Was a problem found?

—

Verify repair

Go to Step 12

12

Check items that can cause the engine to run lean.
Refer to DTC P1171 “Fuel Supply System Lean
During Power Enrichment”.
Was a problem found?

—

Verify repair

Go to Step 13

13

Check for proper ignition voltage output with the spark
tester.
Was a problem found?

—

Verify repair

Go to Step 14

14

Check for a loose ignition control module ground.
Was a problem found?

—

Verify repair

Go to Step 15

15

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

Ω

Verify repair

Go to Step 16

16

1. Check the ignition coil secondary resistance.

2. Replace the coil if it is greater than the specified

resistance.

Did the coil require replacement?

2.5k

Ω

Verify repair

Go to Step 17

17

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 18

18

Check the ECM grounds to verify that they are clean
and tight. Refer to the ECM wiring diagrams.
Was a problem found?

—

Verify repair

Go to Step 19

19

Visually/physically check the vacuum hose for splits,
kinks and proper connections and routing.
Was a problem found?

—

Verify repair

Go to Step 20

Step

Action

Value(s)

Yes

No

ENGINE DRIVEABILITY AND EMISSIONS

6E–247

20

1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

• Visual/physical inspection

• Tech 2 data

• All electrical connections within a suspected

circuit and/or system

Was a problem found?

—

Verify repair

Go to Step 21

21

Is the ECM programmed with the latest software
release? 
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”. 
Was the problem solved?

—

Verify repair

Go to Step 22

22

Replace the ECM. 
Is the action complete? 
IMPORTANT:  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.

—

Verify Repair

—

Step

Action

Value(s)

Yes

No

6E–248

ENGINE DRIVEABILITY AND EMISSIONS

CUTS OUT, MISSES SYMPTOM

DEFINITIONS: Steady pulsation or jerking that follows
engine speed; usually more pronounced as engine load
increases.

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to Step 2

Go 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 4

Go to Visual / 

physical Check.

4

Check the ECM grounds to verify that they are clean
and tight. Refer to the ECM wiring diagrams in
Electrical Diagnosis.
Was a problem found?

—

Verify repair

Go to Step 5

5

Check for a loose or short circuit of ignition coil
module voltage feed.
Was a problem found?

—

Verify repair

Go to Step 6

6

Check for a loose or short circuit of ignition coil
module ground.
Was a problem found?

—

Verify repair

Go to Step 7

7

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

Ω

Verify repair

Go to Step 7

8

Check the CKP sensor wire, shield wire, or installation
condition.
Was a problem found?

—

Verify repair

Go to Step 9

9

Monitor “B1S1 (Bank 1 Sensor 1) Status” on the Tech
2.
Is the “B1S1 (Bank 1 Sensor 1) Status” in the rich
condition?

—

Go to Step 10

Go to Step 11

ENGINE DRIVEABILITY AND EMISSIONS

6E–249

10

Check items that can cause the engine to run rich.
Refer to DTC P1167 “Fuel Supply System Rich During
Deceleration Fuel Cut Off”.
Was a problem found?

—

Verify repair

Go to Step 11

11

Monitor “B1S1 (Bank 1 Sensor 1) Status” on the Tech
2.
Is the “B1S1 (Bank 1 Sensor 1) Status” in the lean
condition?

—

Go to Step 12

Go to Step 13

12

Check items that can cause the engine to run lean.
Refer to DTC P1171 “Fuel Supply System Lean
During Power Enrichment”.
Was a problem found?

—

Verify repair

Go to Step 13

13

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 14

14

Check the injector connectors, if any of the injectors
are connected an incorrect cylinder, correct as
necessary.
Was a problem found?

—

Verify repair

Go to Step 15

15

Perform the “Injector Coil/Balance Test” (Refer to 6E-
98 page). 
Was a problem found.

—

Verify repair

Go to Step 16

16

1. Check for fuel in the pressure regulator vacuum

hose.

2. If fuel is present, replace the fuel pressure

regulator assembly.

Was a problem found?

—

Verify repair

Go to Step 17

17

Check for proper ignition voltage output with the spark
tester.
Was a problem found?

—

Verify repair

Go to Step 18

18

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 19

Step

Action

Value(s)

Yes

No