Isuzu KB P190. Manual - part 584

6E–166

ENGINE DRIVEABILITY AND EMISSIONS

10

Using the DVM and check the heater ground circuit.

1. Ignition “On”, engine “Off”. 

2. Disconnect the O

2

 sensor connector. 

3. Check the circuit for short to voltage circuit. 

Was the DVM indicated voltage?

—

Repair faulty 

harness and 

verify repair

Go to Step 12

11

Replace the O

2

 sensor. 

Was the problem solved?

—

Verify repair

Go to Step 12

12

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 13

13

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

3

V

E77

ENGINE DRIVEABILITY AND EMISSIONS

6E–167

DIAGNOSTIC TROUBLE CODE (DTC) P0201 INJECTOR 1 CONTROL CIRCUIT

DIAGNOSTIC TROUBLE CODE (DTC) P0202 INJECTOR 2 CONTROL CIRCUIT

DIAGNOSTIC TROUBLE CODE (DTC) P0203 INJECTOR 3 CONTROL CIRCUIT

DIAGNOSTIC TROUBLE CODE (DTC) P0204  INJECTOR 4 CONTROL CIRCUIT

Condition for setting the DTC and action taken when the DTC sets

Circuit Description

The engine control module (ECM) has four individual
injector driver circuits. Each controls an injector. When a
driver circuit is grounded by the ECM, the injector is

activated. The ECM monitors the current in each driver
circuit. The ECM measures a voltage drop through a
fixed resistor and controls it. The voltage on each driver
is monitored to detect a fault. If the voltage is not what
the ECM expects to monitor on the circuit, a Diagnostic

Code

Type

DTC Name

DTC Setting Condition

Fail-Safe (Back Up)

P0201

A

Injector 1 Control Circuit

1.  Engine is running. 
2. Engine speed is more than 1000rpm. 
3. Injector voltage does not meet to the bat-

tery voltage when the injector is com-
manded Off or does not meet to the 0V 
when the injector is commanded On.

No fail-safe function.

P0202

A

Injector 2 Control Circuit

P0203

A

Injector 3 Control Circuit

P0204

A

Injector 4 Control Circuit

6E–168

ENGINE DRIVEABILITY AND EMISSIONS

Trouble Code is set. This Diagnostic Trouble Code is
also set if an injector driver is shorted to voltage.

Diagnostic Aids

An injector driver circuit that is open or shorted to
voltage will cause a Diagnostic Trouble Code P0201 to
set. It will also cause a misfire due to an inoperative

injector. A misfire Diagnostic Trouble Code will also be
set indicating which cylinder is inoperative.
Long term and short term fuel trims that are excessively 
high or low are a good indication that an injector is 
faulty. 
Use Fuel Injector Coil Test Procedure to check for faulty
injectors.

Diagnostic Trouble Code (DTC) P0201 Injector 1 Control Circuit

Diagnostic Trouble Code (DTC) P0202 Injector 2 Control Circuit

Diagnostic Trouble Code (DTC) P0203 Injector 3 Control Circuit

Diagnostic Trouble Code (DTC) P0204  Injector 4 Control Circuit

Step

Action

Value(s)

Yes

No

1

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

—

Go  to  Step 2

Go 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 P0201, P0202, P0203 or P0204 stored as
“Present Failure”?

—

Go to Step 3

Refer 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 and

clear the DTC information. 

3. Operate the vehicle and monitor the “F5: Failed

This Ignition” in “F2: DTC Information”.

Was the DTC P0201, P0202, P0203 or P0204 stored
in this ignition cycle?

—

Go to Step 4

Refer to 

Diagnostic Aids 

and Go to Step 

4

4

Check for poor/faulty connection at the injector or
ECM connector. If a poor/faulty connection is found,
repair as necessary. 
Was the problem found?

—

Verify repair

Go to Step 5

5

Visually check the injector for the affected cylinder. 
Was the problem found? 

—

Go to Step 11

Go to Step 6

22

8

9

11

E-60(J1)

E-6/E-7/E-8/E-9

ENGINE DRIVEABILITY AND EMISSIONS

6E–169

6

Using the DVM and check the injector coil for the
affected cylinder.

1.  Ignition “Off”,  engine “Off”. 

2. Disconnect injector connector for the affected

cylinder. 

3. Measure the resistance of injector coil. 

Was the tester indicated specified value? 

Approximately 
12.5

Ω at 20°C

Go to Step 7

Go to Step 11

Step

Action

Value(s)

Yes

No

Injector

Ω

1

2

2

1