Mitsubishi Colt Ralliart. Manual - part 181

TROUBLESHOOTING <CVT>

CVT

23A-67

STEP 41. Check the harness between primary 
speed sensor connector A-116 terminal No.2 and 
engine-CVT-ECU connector A-114 terminal No.43.

AC314200

Connector: A-116

AC

A-116 (B)

Transmission 
control cable

Harness side

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2

3

AC403088AG

A-114

Connector: A-114

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A-114 Harness side connector

Engine-CVT-ECU

Battery

(GR)

Check the output line for open circuit.

Q: Is the check result normal?

YES : 

Go to Step 30.

NO : 

Repair the wiring harness.

STEP 42. Measure the output wave pattern of the 
primary speed sensor at engine-CVT-ECU 
connector A-114 (using an oscilloscope).

AC403088AF

A-114

Connector: A-114

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A-114 Check connector (special tool)

Engine-CVT-ECU

Battery

(GR)

(1) Disconnect the engine-CVT-ECU connector, and 

connect the special tool Power plant ECU check 
harness (MB991987).

(2) Shift the selector lever to the D range.
(3) Accelerate the vehicle to approximately 50 km/h.
(4) Use the special tool Check connector to measure 

the voltage between engine-CVT-ECU connector 
A-114 terminal No.43 and earth.

OK: A wave pattern such as the one 
shown on 

P.23A-128

 (Check Procedure 

Using an Oscilloscope) should be output, 
and the maximum value should be 4.8 V 
or more and the minimum value should 
be 0.6 V or less. There should be no noise 
in the output wave pattern.

Q: Is the check result normal?

YES : 

Go to Step 43.

NO : 

Go to Step 44.

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TROUBLESHOOTING <CVT>

CVT

23A-68

STEP 43. Measure the output wave pattern of the 
secondary speed sensor at engine-CVT-ECU 
connector A-114 (using an oscilloscope).

AC403088AF

A-114

Connector: A-114

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L

A-114 Check connector (special tool)

Engine-CVT-ECU

Battery

(GR)

(1) Disconnect the engine-CVT-ECU connector, and 

connect the special tool Power plant ECU check 
harness (MB991987).

(2) Shift the selector lever to the D range.
(3) Accelerate the vehicle to approximately 50 km/h.
(4) Use the special tool Check connector to measure 

the voltage between engine-CVT-ECU connector 
A-114 terminal No.45 and earth.

OK: A wave pattern such as the one 
shown on 

P.23A-128

 (Check Procedure 

Using an Oscilloscope) should be output, 
and the maximum value should be 4.8 V 
or more and the minimum value should 
be 0.6 V or less. There should be no noise 
in the output wave pattern.

Q: Is the check result normal?

YES : . 

Go to Step 30.

NO : . 

Eliminate the cause of the noise.

STEP 44. Check the primary speed sensor and 
then recheck the diagnosis code.
(1) Remove the primary speed sensor. Wipe any 

metallic particles or dirt off the sensor tip.

(2) Install the primary speed sensor and road test the 

vehicle.

(3) Check if the diagnosis code is set.

Q: Is diagnosis code set?

YES : 

Go to Step 45.

NO : 

The inspection is complete.

STEP 45. Replace the primary speed sensor and 
then recheck the diagnosis code.
(1) Replace the primary speed sensor. (Refer to 

P.23A-155

).

(2) Test drive the vehicle.
(3) Check if the diagnosis code is set.

Q: Is diagnosis code set?

YES : 

Go to Step 46.

NO : 

The inspection is complete.

STEP 46. Replace the CVT assembly and then 
recheck the diagnosis code.
(1) Replace the CVT assembly.
(2) Test drive the vehicle.
(3) Check if the diagnosis code is set.

Q: Is diagnosis code set?

YES : 

Eliminate the cause of the noise.

NO : 

The inspection is complete.

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TROUBLESHOOTING <CVT>

CVT

23A-69

Code No.27, 28 Primary Pressure Sensor System

ENGINE-
CVT-ECU

PRIMARY PRESSURE
SENSOR

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

Primary Pressure Sensor System Circuit

AC405423 AD

OPERATION

The primary pressure sensor measures the fluid 
pressure applied to the primary pulley.

DIAGNOSIS CODE SET CONDITIONS

• If the primary pressure sensor output voltage is 

0.2 V or less while the engine is running (engine 
speed is 450 r/min or more, and the relay voltage 
is 10 V or more), code No.27 will be set.

• If the primary pressure sensor output voltage is 

4.7 V or more (fluid pressure is approximately 6.8 
MPa or more) while the relay voltage is 10 V or 
more, code No.28 will be set.

PROBABLE CAUSES

• Malfunction of primary pressure sensor

• Damaged harness wires and connectors

• Malfunction of the engine-CVT-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list
Item 11: Primary pressure sensor (Refer to Data List 
Table 

P.23A-123

).

Q: Is the check result normal?

YES : 

Intermittent malfunction (Refer to GROUP 

00 

− How to Cope with Intermittent 

Malfunction 

P.00-13

).

NO : 

Go to Step 2.

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TROUBLESHOOTING <CVT>

CVT

23A-70

STEP 2. Connector check: A-118 primary 
pressure sensor connector.

AC206690

AF

Connector: A-118

A-118 (B)

Harness side

1

2

3

Check for the contact with terminals.

Q: Is the check result normal?

YES : 

Go to Step 3.

NO : 

Repair the defective connector.

STEP 3. Measure the resistance at primary 
pressure sensor connector A-118.

AC206690

AF

Connector: A-118

A-118 (B)

Harness side

1

2

3

Disconnect the connector, and measure the resist-
ance between terminal 3 and earth at the wiring har-
ness side.

OK: 2 

Ω or less

Q: Is the check result normal?

YES : 

Go to Step 9.

NO : 

Go to Step 4.

STEP 4. Measure the voltage at engine-CVT-ECU 
connector A-114.
(1) Connect primary pressure sensor connector 

A-118.

AC403088AF

A-114

Connector: A-114

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A-114 Check connector (special tool)

Engine-CVT-ECU

Battery

(GR)

(2) Disconnect the engine-CVT-ECU connector, and 

connect the special tool Power plant ECU check 
harness (MB991987).

(3) Turn the ignition switch to the ON position.
(4) Use the special tool Check connector to measure 

the voltage between engine-CVT-ECU connector 
A-114 terminal No.42 and earth.

OK: 0.5 V or less

Q: Is the check result normal?

YES : 

Go to Step 7.

NO : 

Go to Step 5.

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