Mitsubishi L200. Manual — part 79

TROUBLESHOOTING

DIESEL FUEL

13A-112

Code No. P0117: Engine Coolant Temperature Sensor Circuit Low Input

OPERATION

• A power voltage of 5 V is applied to the engine

coolant temperature sensor output terminal (ter-
minal No. 1) from the engine-ECU (terminal No.
63).

• The power voltage is earthed to the engine-ECU

(terminal No. 87) from the engine coolant temper-
ature sensor (terminal No. 2).

FUNCTION

• The engine coolant temperature sensor converts

the engine coolant temperature into a voltage sig-
nal, and inputs the voltage to the engine-ECU.

• In response to the signal, the engine-ECU con-

trols the fuel infection amount and the fast idle
speed when the engine is cold state.

• The engine coolant temperature sensor is a kind

of resistor, which has characteristics to reduce its
resistance as the engine coolant temperature
rises. Therefore, the sensor output voltage varies
with the engine coolant temperature, and
becomes lower as the engine coolant tempera-
ture rises.

TROUBLE JUDGMENT

Check Conditions

• Battery positive voltage is 8 − 16 V

• 2 seconds later after the ignition switch has been

in "ON" position or the engine has started up.

Judgment Criterion

• The engine coolant temperature sensor output

voltage is 0.15 V or less for 0.5 second.

PROBABLE CAUSES

• Failed engine coolant temperature sensor

AKA00095

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LG

V

Engine-ECU

Engine coolant
temperature sensor

A-107

(MU802406)

C-105

Engine Coolant Temperature Sensor Circuit

Wire colour code
B: Black LG: Light green G: Green L: Blue W: White Y: Yellow SB: Sky blue BR: Brown O: Orange GR: Grey
R: Red P: Pink V: Violet PU: Purple SI: Silver

2

87

1

63

AB

TROUBLESHOOTING

DIESEL FUEL

13A-113

• Short circuit or harness damage in engine cool-

ant temperature sensor circuit or loose connector
contact

• Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

• Item 7: Engine coolant temperature sensor

OK:

Engine cold state: At ambient temperature

(atmospheric temperature) or equivalent.

Engine hot state: At 80

− 120°C

Q: Is the check result normal?

YES :

Intermittent malfunction (Refer to GROUP

00

− How to Use Troubleshooting/

Inspection Service Points

− How to Cope

with Intermittent Malfunctions ).

NO :

Go to Step 2 .

STEP 2. Connector check: A-107 engine coolant
temperature sensor connector

Q: Is the check result normal?

YES :

Go to Step 3 .

NO :

Repair or replace the connector.

STEP 3. Perform resistance measurement at A-
107 engine coolant temperature sensor
connector.

• Disconnect connector, and measure at sensor

side.

• Resistance between terminal No. 1 and No. 2.

OK:

Engine coolant temperature at

−20°C: 14 − 17

k

Ω

Engine coolant temperature at 0

°C: 5.1 − 6.5

k

Ω

Engine coolant temperature at 20

°C: 2.1 − 2.7

k

Ω

Engine coolant temperature at 40

°C: 0.9 − 1.3

k

Ω

Engine coolant temperature at 60

°C: 0.48 −

0.68 k

Ω

Engine coolant temperature at 80

°C: 0.26 −

0.36 k

Ω

Q: Is the check result normal?

YES :

Go to Step 4 .

NO :

Replace the engine coolant temperature
sensor.

STEP 4. Perform voltage measurement at A-107
engine coolant temperature sensor connector.

• Disconnect connector, and measure at harness

side.

• Ignition switch: ON

• Voltage between terminal No. 1 and earth.

OK: 4.5

− 4.9 V

Q: Is the check result normal?

YES :

Go to Step 8 .

NO :

Go to Step 5 .

AK501323

1

2

AB

A-107 (B)

Harness side
connector

Connector: A-107

AK501323

1

2

AB

A-107 (B)

Harness side
connector

Connector: A-107

AK501323

1

2

AB

A-107 (B)

Harness side
connector

Connector: A-107

TROUBLESHOOTING

DIESEL FUEL

13A-114

STEP 5. Connector check: C-105 engine-ECU
connector

Q: Is the check result normal?

YES :

Go to Step 6 .

NO :

Repair or replace the connector.

STEP 6. Check harness between A-107 (terminal
No. 1) engine coolant temperature sensor
connector and C-105 (terminal No. 63) engine-
ECU connector.

• Check output line for short circuit.

Q: Is the check result normal?

YES :

Go to Step 7 .

NO :

Repair the damaged harness wire.

STEP 7. M.U.T.-III data list

• Item 7: Engine coolant temperature sensor

OK:

Engine cold state: At ambient temperature

(atmospheric temperature) or equivalent.

Engine hot state: At 80

− 120 °C

Q: Is the check result normal?

AKA00089

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C-105 (B)

C-105 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-105

AB

AK501323

1

2

AB

A-107 (B)

Harness side
connector

Connector: A-107

AKA00089

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C-105 (B)

C-105 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-105

AB

TROUBLESHOOTING

DIESEL FUEL

13A-115

YES :

Intermittent malfunction (Refer to GROUP

00

− How to Use Troubleshooting/

Inspection Service Points

− How to Cope

with Intermittent Malfunctions ).

NO :

Replace the engine-ECU. When the engine-
ECU is replaced, write the chassis number
(Refer to GROUP 00

− Precautions Before

Service

− How to Perform Chassis Number

Writing ). After replacing the engine-ECU,
register the injector identification code and
learn fuel injection (Refer to GROUP 00

−

Precautions Before Service

− What The

Common Rail Engine Learns ). After
registering the injector identification code,
the vehicle equipped with the DPF carries
out the forcible DPF regeneration. (Refer to
GROUP 17

− Emission Control − Diesel

Particulate Filter (DPF) System

− Forcible

DPF Regeneration ).

STEP 8. Perform resistance measurement at A-
107 engine coolant temperature sensor
connector.

• Disconnect connector, and measure at harness

side.

• Resistance between terminal No. 2 and earth.

OK: Continuity (2

Ω or less)

Q: Is the check result normal?

YES :

Go to Step 11 .

NO :

Go to Step 9 .

STEP 9. Connector check: C-105 engine-ECU
connector

Q: Is the check result normal?

YES :

Go to Step 10 .

NO :

Repair or replace the connector.

AK501323

1

2

AB

A-107 (B)

Harness side
connector

Connector: A-107

AKA00089

1

2

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C-105 (B)

C-105 (B)

<R.H. drive vehicles>

Harness side connector

<L.H. drive vehicles>

Connector: C-105

AB