Isuzu KB P190. Manual - part 589

6E–186

ENGINE DRIVEABILITY AND EMISSIONS

DIAGNOSTIC TROUBLE CODE (DTC) P0351 IGNITION 1 CONTROL CIRCUIT

DIAGNOSTIC TROUBLE CODE (DTC) P0352 IGNITION 2 CONTROL CIRCUIT

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

Circuit Description

The ignition control circuit provides a zero volt or a 5 volt
signal to the ignition control module. The normal circuit
voltage is zero volts. When the module receives the 5
volt signal from the ECM, it provides a ground path for
the B+ voltage supplied to the ignition primary coil.
When the ECM turns off the 5 volts to the module, the
module will remove the ground path of the ignition
primary coils; causing the magnetic field produces a
voltage in the secondary coils which fires the spark
plug.

The circuit between the ECM and the ignition control
module is monitored for an open circuit, short to voltage,
and short to ground. When the ECM detects a problem
in the ignition control circuit, it will set DTC P0351 or
P0352.

Diagnostic Aids

Check for the following conditions:

• Poor connection at the ECM - Inspect the harness

connectors for backed-out terminals, improper

Code

Type

DTC Name

DTC Setting Condition

Fail-Safe (Back Up)

P0351

A

Ignition 1 Control Circuit 

#1 or #4cylinder ignition signals are not 
detected consecutively.

No fail-safe function.

P0352

A

Ignition 2 Control Circuit 

#2 or #3 cylinder ignition signals are not 
detected consecutively.

ENGINE DRIVEABILITY AND EMISSIONS

6E–187

mating, broken locks, improperly formed or damaged
terminals, and poor terminal-to-wire connections.

• Damaged harness - Inspect the wiring harness for

damage; Open circuits, shorts to ground, or shorts to
Voltage. If the harness appears to be OK, observe

the Tech 2 display related to DTC P0351 or P0352
while moving the connector and wiring related to the
ignition system. A change in the display will indicate
the location of the fault.

Diagnostic Trouble Code (DTC) P0351 Ignition 1 Control Circuit

Diagnostic Trouble Code (DTC) P0352 Ignition 2 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 P0351 or P0352 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 P0351 or P0352 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 ignition coil
module 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 ignition coil module. 
Was the problem found?

—

Go to Step 12

Go to Step 6

19

18

E-60(J1)

E-18

6E–188

ENGINE DRIVEABILITY AND EMISSIONS

6

Using the DVM and check the ignition coil module
signal circuit for the affected coil. 

1.  Ignition “On”, engine “Off”. 

2. Disconnect the ignition coil module connector. 

3. Check the circuit for short to battery voltage circuit

for the affected coil. 

Was the DVM indicated battery voltage?

—

Repair faulty 

harness and 

verify repair

Go to Step 7

Step

Action

Value(s)

Yes

No

E-18

1

11

1

Coil 2

V

E-18

3

33

3

Coil 1

V

ENGINE DRIVEABILITY AND EMISSIONS

6E–189

7

Using the DVM and check the ignition coil signal
circuit for the affected coil.
Breaker box is available: 

1. Ignition “Off”, engine “Off”. 

2. Install the breaker box as type A. (ECM

disconnected) Refer to 6E-88 page.

3. Disconnect the ignition coil module connector. 

4. Check the circuit for open or short to ground circuit

for the affected coil. 

Was the problem found?

Breaker box is not available: 

1. Ignition “Off”, engine “Off”. 

2. Disconnect the ignition coil module connector and

ECM connector. 

3. Check the circuit for open or short to ground circuit

for the affected coil. 

Was the problem found?

—

Repair faulty 

harness and 

verify repair

Go to Step 8

Step

Action

Value(s)

Yes

No

J1-18

Breaker Box

E-18

1

Coil 2

Ω

Ω

J1-19

Breaker Box

E-18

3

Coil 1

Ω

Ω

E-18

1

Coil 2

Ω

Ω

E-60(J1)

18

E-18

3

Coil 1

Ω

Ω

E-60(J1)

19