Isuzu N-Series. Manual - part 675

6E-122    Engine Control System (4HK1) 

4

1.

Test the signal circuit between the engine
control module (ECM) (pin 83 of E-111
connector) and the FT sensor (pin 2 of E-93
connector) for the following conditions:

• A short to ground
• A short to the low reference circuit

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 6

5

Replace the FT sensor. Refer to Fuel Temperature
(FT) Sensor Replacement in this section.

Did you complete the replacement?

—

Go to Step 8

—

6

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect connections on the FT sensor circuits
at the harness connector of the ECM (pins 83
and 109 of E-111 connector) for corrosion.

4.

Repair or clean the connection(s) as
necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 7

7

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 8

—

8

1.

Reconnect all previously disconnected
harness connector(s).

2.

Clear the DTCs with the Tech 2.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine.

5.

Operate the vehicle within the Conditions for
Running the DTC.

Did the DTC fail this ignition?

—

Go to Step 2

Go to Step 9

9

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

No

 Engine Control System (4HK1)    6E-123

P0183 (Flash Code 211)

Circuit Description
The fuel temperature (FT) sensor is installed to the fuel
supply pump. The FT sensor is a variable resistor. The
FT sensor has a signal circuit and a low reference
circuit. The FT sensor measures the fuel temperature
of the fuel. The engine control module (ECM) supplies
5 volts to the FT signal circuit and a ground for the FT
low reference circuit. When the FT sensor is cold, the
sensor resistance is high. When the fuel temperature
increases, the sensor resistance decreases. With high
sensor resistance, the ECM detects a high voltage on
the FT signal circuit. With lower sensor resistance, the
ECM detects a lower voltage on the FT signal circuit. If
the ECM detects an excessively high FT signal voltage,
this DTC will set.

Condition for Running the DTC

• DTCs P1630 and P1634 are not set.
• The ignition switch is ON.
• The ignition voltage is more than 18 volts.
• The engine run time is longer than 3 minutes.

Condition for Setting the DTC

• The ECM detects that the FT sensor signal voltage

is more than 4.8 volts for 10 seconds.

Action Taken When the DTC Sets

• The ECM illuminates the malfunction indicator

lamp (MIL) when the diagnostic runs and fails.

• The ECM uses a FT substitution of -20

°C (-4°F) for

engine starting control.

• The ECM uses a FT substitution of 70

°C (158°F)

for engine control.

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.

• A history DTC clears after 20 consecutive driving

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

Diagnostic Aid

• Before starting a cold engine, FT sensor and

engine coolant temperature (ECT) sensor
temperature should be relatively close to each
other.

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

• Use the Temperature vs. Resistance table to test

the ECT sensor at various temperature levels to
evaluate the possibility of a skewed sensor. A
skewed sensor could result in poor driveability
concerns.

DTC P0183 (Flash Code 211)
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

No

1

Did you perform the Diagnostic System Check –
Engine Controls?

—

Go to Step 2

Go to Diagnostic 

System Check – 

Engine Controls

2

1.

Install the Tech 2.

2.

Turn OFF the ignition for 30 seconds.

3.

Turn ON the ignition, with the engine OFF.

4.

Observe the Fuel Temperature (FT) Sensor
parameter with the Tech 2.

Is the FT Sensor parameter more than the
specified value?

4.8 volts

Go to Step 3

Go to Diagnostic 

Aids

3

1.

Turn OFF the ignition.

2.

Disconnect the FT sensor harness connector.

3.

Connect a DMM between the signal circuit of
the FT sensor harness (pin 2 of E-93
connector) and a known good ground.

4.

Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

5.5 volts

Go to Step 4

Go to Step 5

6E-124    Engine Control System (4HK1) 

4

Important:
The FT sensor may be damaged if the sensor
signal circuit is shorted to a voltage source.

1.

Test the signal circuit between the engine
control module (ECM) (pin 83 of E-111
connector) and the FT sensor (pin 2 of E-93
connector) for a short to battery or ignition
voltage.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 13

5

1.

Turn OFF the ignition.

2.

Connect a test lamp between the signal circuit
of the FT sensor harness (pin 2 of E-93
connector) and a known good ground.

3.

Connect a DMM between the probe of the test
lamp and a known good ground.

4.

Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

4.5 volts

Go to Step 9

Go to Step 6

6

1.

Turn OFF the ignition.

2.

Connect a 3-amp fused jumper wire between
the signal circuit and low reference circuit of
the FT sensor harness (pins 1 and 2 of E-93
connector).

3.

Turn ON the ignition, with the engine OFF.

4.

Observe the FT Sensor parameter with the
Tech 2.

Is the FT Sensor parameter less than the specified
value?

0.1 volts

Go to Step 10

Go to Step 7

7

1.

Test the signal circuit between the ECM (pin
83 of E-111 connector) and the FT sensor (pin
2 of E-93 connector) for an open circuit or high
resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 8

8

1.

Test the low reference circuit between the
ECM (pin 109 of E-111 connector) and the FT
sensor (pin 1 of E-93 connector) for an open
circuit or high resistance.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 11

9

1.

Test the signal circuit between the ECM (pin
83 of E-111 connector) and the FT sensor (pin
2 of E-93 connector) for a short to any 5 volts
reference circuit.

2.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 13

10

1.

Turn OFF the ignition.

2.

Inspect for an intermittent and for poor
connections at the harness connector of the
FT sensor (pins 1 and 2 of E-93 connector).

3.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 12

Step

Action

Value(s)

Yes

No

 Engine Control System (4HK1)    6E-125

11

1.

Turn OFF the ignition.

2.

Disconnect the ECM harness connector.

3.

Inspect for an intermittent and for poor
connections on the FT sensor circuits at the
harness connector of the ECM (pins 83 and
109 of E-111 connector).

4.

Repair the connection(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 13

12

Replace the FT sensor. Refer to Fuel Temperature
(FT) Sensor Replacement in this section.

Did you complete the replacement?

—

Go to Step 14

—

13

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 14

—

14

1.

Reconnect all previously disconnected
harness connector(s).

2.

Clear the DTCs with the Tech 2.

3.

Turn OFF the ignition for 30 seconds.

4.

Start the engine.

5.

Operate the vehicle within the Conditions for
Running the DTC.

Did the DTC fail this ignition?

—

Go to Step 2

Go to Step 15

15

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

No