Isuzu N-Series. Service manual - part 678

6E-134 Engine Control System (4HK1)

Turn OFF the ignition.

Disconnect the ECM harness connector.

Inspect for an intermittent and for a poor
connection on the cylinder number 1 fuel
injector control circuit at the harness
connector of the ECM (pin 119 of E-111
connector).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 14

Important:
Replacement injector must be programmed.

Replace the cylinder number 1 fuel injector. Refer
to Fuel Injector Replacement / Fuel Injector ID
Code Data Programming in this section.

Did you complete the replacement?

—

Go to Step 15

—

Important:
Replacement ECM must be programmed.

Replace the ECM. Refer to Engine Control Module
(ECM) Replacement / Fuel Injector ID Code Data
Programming in this section.

Did you complete the replacement?

—

Go to Step 15

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with the Tech 2.

Turn OFF the ignition for 30 seconds.

Start the engine.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 16

Observe the DTC Information with the Tech 2.

Are there any DTCs that you have not diagnosed?

—

Go to Diagnostic

Trouble Code (DTC)

List

System OK

Step

Action

Value(s)

Yes

Engine Control System (4HK1) 6E-135

P0202 (Flash Code 272)

Circuit Description
The engine control module (ECM) calculates the
optimum fuel injection ON time using data sent from
various engine sensors. The ECM supplies a high
voltage along with grounding the fuel injector control
circuit when it needs to energize the fuel injector (turn it
ON). The ECM also supplies battery voltage to the fuel
injector solenoid control circuit to allow for fault
detection. If the cylinder number 2 fuel injector solenoid
control circuit is open circuit, shorted to voltage or
shorted to the common 2 fuel injector drive circuit, this
DTC will set.

Condition for Running the DTC

• DTCs P0203, P0612 and P1262 are not set.
• The ignition switch is ON.
• The battery voltage is more than 18 volts.
• The engine is running.

Condition for Setting the DTC

• The ECM detects that the cylinder number 2 fuel

injector solenoid coil control circuit is open circuit,
shorted to voltage or shorted to common 2 fuel
injector drive circuit during engine rotations.

Action Taken When the DTC Sets

• The ECM illuminates the malfunction indicator

lamp (MIL) when the diagnostic runs and fails.

Condition for Clearing the MIL / DTC

• The ECM turns OFF the MIL when the key is

cycled after a current DTC clears.

• A current DTC clears when the diagnostic runs and

does not fail at next driving cycle.

• A history DTC clears after 20 consecutive driving

cycles without a fault. Or clear with the Tech 2 or
accelerator pedal operation.

Diagnostic Aid

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

DTC P0202 (Flash Code 272)
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views

Step

Action

Value(s)

Yes

Did you perform the Diagnostic System Check –
Engine Controls?

—

Go to Step 2

Go to Diagnostic

System Check –

Engine Controls

Install the Tech 2.

Turn OFF the ignition for 30 seconds.

Start the engine.

Monitor the Diagnostic Trouble Code (DTC)
Information with the Tech 2.

Does the DTC fail this ignition?

—

Go to Step 3

Go to Diagnostic

Aids

Turn OFF the ignition.

Disconnect the in-line harness connector (H-
125) from the cylinder head cover case.

Connect a DMM between the common 2 fuel
injector drive circuit (pin 2 of H-125 female
side connector) and a known good ground.

Turn ON the ignition, with the engine OFF.

Is the DMM voltage less than the specified value?

1.0 volt

Go to Step 4

Go to Step 9

Connect a DMM between the cylinder number 2
fuel injector control circuit (pin 6 of H-125 female
side connector) and a known good ground.

Is the DMM voltage less than the specified value?

16.0 volts

Go to Step 5

Go to Step 10

Is the DMM voltage more than the specified value
at Step 4?

12.0 volts

Go to Step 6

Go to Step 11

6E-136 Engine Control System (4HK1)

Inspect for an intermittent and for a poor
connection at the in-line harness connector
(pin 6 of H-125 connector).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 7

Remove the cylinder head cover. Refer to Fuel
Injector Replacement in this section.

Inspect the fuel injector harness for loose
injector terminal nuts, objects touching injector
terminals.

Inspect for an intermittent and for a poor
connection at the in-line harness connector
(pin 6 of H-126 connector).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 8

Test the cylinder number 2 fuel injector
solenoid control circuit between the fuel
injector terminal (pins 1, 2 and 3 of E-139
connector) and the in-line harness connector
(pins 2, 3 and 6 of H-126 connector) for the
following conditions:

• An open circuit
• A short to the common 2 fuel injector

drive circuit

• High resistance

Repair or replace the injector harness as
necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 13

Test the cylinder number 2 fuel injector
solenoid control circuit and common 2 fuel
injector drive circuit for a short to each other
between the engine control module (ECM)
(pins 116 and 118 of E-111 connector) and the
in-line harness connector (pins 2 or 3 and 6 of
H-125 connector).

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 14

Test the cylinder number 2 fuel injector
solenoid control circuit between the ECM (pin
118 of E-111 connector) and the in-line
harness connector (pin 6 of H-125 connector)
for a short to battery or ignition voltage.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 14

Test the cylinder number 2 fuel injector
solenoid control circuit between the ECM (pin
118 of E-111 connector) and the in-line
harness connector (pin 6 of H-125 connector)
for an open circuit or high resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 12

Step

Action

Value(s)

Yes

Engine Control System (4HK1) 6E-137

Turn OFF the ignition.

Disconnect the ECM harness connector.

Inspect for an intermittent and for a poor
connection on the cylinder number 2 fuel
injector control circuit at the harness
connector of the ECM (pin 118 of E-111
connector).

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 15

Go to Step 14

Important:
Replacement injector must be programmed.

Replace the cylinder number 2 fuel injector. Refer
to Fuel Injector Replacement / Fuel Injector ID
Code Data Programming in this section.

Did you complete the replacement?

—

Go to Step 15

—

Important:
Replacement ECM must be programmed.

Replace the ECM. Refer to Engine Control Module
(ECM) Replacement / Fuel Injector ID Code Data
Programming in this section.

Did you complete the replacement?

—

Go to Step 15

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with the Tech 2.

Turn OFF the ignition for 30 seconds.

Start the engine.

Did the DTC fail this ignition?

—

Go to Step 3

Go to Step 16

Observe the DTC Information with the Tech 2.

Are there any DTCs that you have not diagnosed?

—

Go to Diagnostic

Trouble Code (DTC)

List

System OK

Step

Action

Value(s)

Yes

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