Isuzu KB P190. Manual - part 432

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-111

Test each sensor circuit between the ECM
(pins 26 and 27 of E-90) and the ECT sensor
(pins 1 and 2 of E-41) for high resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 6

Go to Step 5

Replace the ECT sensor. Refer to ECT Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 6

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Cool down the engine as necessary (allow
engine coolant temperature to cool down at
least 50

°C [122°F]).

Start the engine and wait until engine is warm
upped while comparing the Coolant
Temperature parameter on the scan tool to the
water temperature gauge on the instrument
panel (IP) cluster.

Does the Coolant Temperature rise from 50 to 80

°C

(122 to 176

°F) in proportion to the coolant

temperature gauge indicates from lowest scale to
slightly below middle?

—

Go to Step 7

Go to Step 2

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

6E-112 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

DTC P0117 or P0118 (Flash Code 23)

Circuit Description

The engine coolant temperature (ECT) sensor is
installed to the thermostat housing. The ECT sensor is
a variable resistor and it measures the temperature of
the engine coolant. The sensor has a signal circuit and
a low reference circuit. The ECM supplies 5 volts to the
signal circuit and a ground for the low reference circuit.
When the ECT sensor is cold, the sensor resistance is
high. When the engine coolant temperature increases,
the sensor resistance decreases. With high sensor
resistance, the ECM detects a high voltage on the
signal circuit. With lower sensor resistance, the ECM
detects a lower voltage on the signal circuit. If the ECM
detects an excessively low or high signal voltage, DTC
P0117 or P0118 will set.

Condition for Running the DTC

• The battery voltage is more than 9 volts.

• The ignition switch is ON.

• The engine run time is longer than 3 minutes.

(DTC P0118)

Condition for Setting the DTC

• The ECM detects that the ECT sensor signal

voltage is less than 0.1 volts for 3 seconds. (DTC
P0117)

• The ECM detects that the ECT sensor signal

voltage is more than 4.75 volts for 3 seconds.
(DTC P0118)

Action Taken When the DTC Sets

• The ECM illuminates the MIL when the diagnostic

runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.

• The ECM uses an ECT substitution of default

value.

• The ECM limits fuel injection quantity.

• The ECM inhibits EGR control.

• The ECM inhibits cruise control.

Condition for Clearing the DTC

• Refer to DTC Type Definitions for Condition for

Clearing the MIL/ DTC - Type A.

Diagnostic Aids

• 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.

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing DTC P0117

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 a scan tool.

Turn OFF the ignition for 30 seconds.

Turn ON the ignition, with the engine OFF.

Observe the Engine Coolant Temperature
(ECT) Sensor parameter with a scan tool.

Is the ECT Sensor parameter less than the
specified value?

0.1 volts

Go to Step 3

Go to Diagnostic

Aids

Turn OFF the ignition.

Disconnect the ECT sensor harness
connector.

Turn ON the ignition, with the engine OFF.

Is the ECT Sensor parameter more than the
specified value?

4.7 volts

Go to Step 5

Go to Step 4

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-113

Circuit/ System Testing DTC P0118

Test the signal circuit between the ECM (pin
27 of E-90) and the ECT sensor (pin 1 of E-
41) for the following conditions:

• A short to ground

• A short to the low reference circuit

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 6

Replace the ECT sensor. Refer to ECT Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 8

—

Turn OFF the ignition.

Disconnect the ECM harness connector.

Inspect connections at the harness connector
of the ECM (pins 26 and 27 of E-90) for
corrosion.

Repair or clean the connection(s) as
necessary.

Did you find and correct the condition?

—

Go to Step 8

Go to Step 7

Important: Replacement ECM must be
programmed and learned.
Replace the ECM. Refer to ECM Replacement.

Did you complete the replacement?

—

Go to Step 8

—

Reconnect all previously disconnected
harness connector(s).

Clear the DTCs with a scan tool.

Turn OFF the ignition for 30 seconds.

Start the engine.

Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within the conditions that you
observed from the Freeze Frame/ Failure
Records.

Did the DTC fail this ignition?

—

Go to Step 2

Go to Step 9

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

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 a scan tool.

Turn OFF the ignition for 30 seconds.

Turn ON the ignition, with the engine OFF.

Observe the Engine Coolant Temperature
(ECT) Sensor parameter with a scan tool.

Is the ECT Sensor parameter more than the
specified value?

4.7 volts

Go to Step 3

Go to Diagnostic

Aids

6E-114 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Turn OFF the ignition.

Disconnect the ECT sensor harness
connector.

Connect a DMM between the signal circuit
(pin 1 of E-41) and a known good ground.

Turn ON the ignition, with the engine OFF.

Is the DMM voltage more than the specified value?

5.3 volts

Go to Step 4

Go to Step 5

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

Test the signal circuit between the ECM (pin
27 of E-90) and the ECT sensor (pin 1 of E-
41) for a short to battery or ignition voltage.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 13

Connect a 3-amp fused jumper wire between the
signal circuit and the low reference circuit (pins 1
and 2 of E-41).

Is the Engine Coolant Temperature Sensor
parameter less than the specified value?

0.1 volts

Go to Step 9

Go to Step 6

Connect a 3-amp fused jumper wire between the
signal circuit (pin 1 of E-41) and a known good
ground.

Is the Engine Coolant Temperature Sensor
parameter less than the specified value?

0.1 volts

Go to Step 8

Go to Step 7

Test the signal circuit between the ECM (pin
27 of E-90) and the ECT sensor (pin 1 of E-
41) for an open circuit or high resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 11

Test the low reference circuit between the
ECM (pin 26 of E-90) and the ECT sensor (pin
2 of E-41) for an open circuit or high
resistance.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 11

Test the signal circuit between the ECM (pin
27 of E-90) and the ECT sensor (pin 1 of E-
41) for a short to any 5 volts reference circuit.

Repair the circuit(s) as necessary.

Did you find and correct the condition?

—

Go to Step 14

Go to Step 10

Inspect for an intermittent and for poor
connections at the harness connector of the
ECT sensor (pins 1 and 2 of E-41).

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

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