Mitsubishi Pajero Pinin. Manual - part 176

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-14

Code No. 55 Abnormal communication with engine-ECU

Probable cause

If normal communication is not possible for a continuous period of 1 second or
more when the ignition switch is at the ON position and the battery voltage is 10
V or more, diagnosis code No. 55 is output. Diagnosis code No. 55 is also output
if the data being received is abnormal for a continuous period of 1 second under
the same conditions.

D

Malfunction of harness or connector

D

Malfunction of the engine-ECU

D

Malfunction of the A/T-ECU

MUT-

II

 Self-Diag code

D

Is the diagnosis code No.61 output?

NO

YES

Check the following connectors:
<L.H. vehicles> C-19, C-25, D-34, D-04
<R.H. vehicles> C-19, C-26, D-34, D-04

NG

Repair

OK

Check the harness wire between engine-ECU and A/T-ECU.

NG

Repair

OK

Replace the engine-ECU.

Check the trouble symptoms.

NG

Replace the A/T-ECU.

Replace the A/T-ECU.

Check the trouble symptoms.

NG

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-15

INSPECTION CHART FOR TROUBLE SYMPTOMS

Trouble symptom

Inspection procedure
No.

Reference page

Communication with the MUT-

II

 is not possible

1

23-16

Does not move

Does not move forward and reverse

2

23-17

Does not move forward only

3

23-18

Does not reverse only

4

23-18

Malfunction when
shifting

Upshifting does not occur

5

23-19

shifting

Downshifting does not occur

6

23-20

Shifting point abnormality

7

23-20

Upshifting occurs spontaneously

8

23-21

Incorrect drive gear position

9

23-21

Large shocks

10

23-22

Slippage (vibration)

11

23-23

Lockup malfunction

12

23-24

Abnormal engine braking

13

23-24

Electronic circuit
systems

Inhibitor switch system

14

23-25

systems

Overdrive switch system

15

23-25

Stop lamp switch system

16

23-26

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-16

INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS

INSPECTION PROCEDURE 1

Communication with the MUT-

II

 is not possible

Probable cause

If communication with the MUT-

II

 is not possible, the cause is probably a malfunction

in the self-diagnosis system or the A/T-ECU is not functioning.

D

Malfunction of self-diagnosis system

D

Malfunction of A/T-ECU power circuit

D

Malfunction of A/T-ECU earth circuit

D

Malfunction of A/T-ECU

D

Malfunction of harness and connector

Is communication with other systems
possible using the MUT-

II

?

No

Check and repair the self-diagnosis 
system with the MUT-

II

Yes

Measure at A/T-ECU connector D-04

D

Disconnect the connector and
measure at the harness side.

D

Voltage between terminals (9) and
(24) and the earth
OK: System voltage

D

Continuity between terminal (25)
and earth
OK: Continuity

OK

Check the following connectors:
<L.H. drive vehicles> D-04, D-34, C-37,
C-70, C-35
<R.H. drive vehicles> D-04, D-34, C-39,
C-70, C-35

NG

Repair

OK

Check the trouble symptoms.

NG

Replace the A/T-ECU.

NG

Check the following connectors:
<L.H. drive vehicles> D-02, C-24, C-78,
C-74, D-34, C-68, C-72
<R.H. drive vehicles> D-02, C-26, C-78,
C-74, D-34, C-68, C-72

NG

Repair

OK

Check the trouble symptoms.

NG

D

Check and repair the harness wire
between the A/T-ECU and the
power supply.

D

Check and repair the harness wire
between the A/T-ECU and the earth.

Check the trouble symptoms

NG

Replace the A/T-ECU.

AUTOMATIC TRANSMISSION – 

Troubleshooting <A/T>

23-17

INSPECTION PROCEDURE 2

Does not move forward and reverse

Probable cause

When the engine is idling, the vehicle does not move forward and reverse even
if the selector lever is shifted from N to D, 2, L or R positionj. In such cases, the
cause is probably abnormal line pressure, or a malfunction of the transmission control
cable, torque converter, oil pump, parking mechanism or the power train.

D

Malfunction of transmission control cable

D

Abnormal line pressure

D

Malfunction of power train

D

Malfunction of oil pump

D

Malfunction of valve body

D

Malfunction of parking mechanism

D

Malfunction of torque converter

D

Malfunction of A/T-ECU

L

: Refer to the Transmission Workshop Manual.

OK

Replace the torque converter. 

L

NG

Check and repair or replace the oil
pump. 

L

Check the trouble symptoms

Is abnormal noise generated in D
range?

Yes

Is the source of the abnormal noise
the torque converter or thetransmis-
sion?

Replace the torque converter 

L

Torque 
converter

No

Transmission

Check the power train. 

L

D

Disassemble the transmission,
check the condition of the planetary
gear and other parts, and repair or
replace any parts as necessary.

Can the propeller shaft be turned by
hand in all ranges except P range?

No

Malfunction of parking mechanism 

L

Yes

Check the line pressure. 
(Refer to P. 23-45.)

NG

Repair or replace the valve body. 

L

Transmission control cable assembly
check

NG

NG

OK

OK

Check the engine control system, igni-
tion system, fuel system, engine me-
chanical system.

Repair, replace

Repair, replace

Check the trouble symptoms.

NG

Replace the A/T-ECU.