Mitsubishi Montero (2004+). Manual — part 926

AUTOMATIC TRANSMISSION DIAGNOSIS

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AUTOMATIC TRANSMISSION

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LOGIC FLOW CHARTS (Monitor Sequence)

.

DTC SET CONDITIONS (ENTRY CONDITIONS
AND MALFUNCTION THRESHOLDS)

Check Conditions

• Voltage of battery: 9 volts or more.

• Time after PCM turns on A/T control relay: 0.5

second or more.

Judgement Criteria

• A/T control relay output voltage: 7 volts or less.

(0.1 second)

• If DTC 54 (P1751) is set consecutively four times,

the transmission is locked into 3rd gear as a
fail-safe measure, and the "N" range light flashes
once per second.

.

OBD-II DRIVE CYCLE PATTERN
Start the engine, and keep the vehicle stopped in P
range for 5 seconds.

.

AC205241

START

END

No

Malfunction

Yes

Good

No

Yes

No

Yes

No

Yes

No

Yes

Timer start

TCM turn on A/T
control relay

Timer > 0.5 sec.

Voltage of battery > 9 V

Output voltage from
control relay < 7 V

Continuous failure
for 0.1 sec.

PCM

AB

AUTOMATIC TRANSMISSION DIAGNOSIS

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AUTOMATIC TRANSMISSION

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TROUBLESHOOTING HINTS (THE MOST LIKELY
CAUSES FOR THIS CODE TO BE SET ARE:)

• Malfunction of the A/T control relay

• Damaged harness, connector

• Malfunction of the PCM

DIAGNOSIS

Required Special Tool:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, check data list item 54:
A/T Control Relay Output Voltage.

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to the data reading mode.

• Item 54: A/T Control Relay Output Voltage.

• The voltage should equal battery positive voltage.

(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage equal battery positive voltage?

YES : It can be assumed that this malfunction is intermittent.

Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points

− How to

Cope with Intermittent Malfunction

P.00-6

.

NO : Go to Step 2.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

AUTOMATIC TRANSMISSION DIAGNOSIS

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STEP 2. Check the A/T control relay.
(1) Remove the A/T control relay (A/T control relay connector

D-13).

(2) Using jumper wires, connect terminal 2 to the negative

battery terminal, and terminal 4 to the positive battery
terminal.

(3) Measure the resistance between terminal 1 and 3 of the A/T

control relay.

• The resistance should measure less than 2 ohms.

• Disconnect the jumper wires. The resistance between

terminals 1 and 3 should measure over limits (open cir-
cuit).

Q: Is the measured resistance less than 2 ohms when the

relay is energized, and open circuit when the relay is
de-energized?
YES : Go to Step 3.
NO : Replace the A/T control relay.

STEP 3. Check A/T control relay connector D-13 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Are the connector and terminals in good condition?

YES : Go to Step 4.
NO : Repair or replace the damaged components. Refer to

GROUP 00E, Harness Connector Inspection

P.00E-2

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AC204750

CONNECTOR : D-13

AB

PCM

1
3 4

2

AC204947

1
3 4

2

D-13 HARNESS CONNECTOR :
A/T CONTROL RELAY SIDE

AB

AC204750

CONNECTOR : D-13

AB

PCM

1
3 4

2

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STEP 4. Measure the supply voltage at A/T control relay
connector D-13.
(1) Disconnect the A/T control relay and measure at the

harness side.

(2) Measure the voltage between terminal 1 and ground.

• The measured voltage should equal battery positive

voltage.

Q: Is the measured voltage equal to battery positive

voltage?
YES : Go to Step 7.
NO : Go to Step 5.

STEP 5. Check intermediate connector A-03 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Are the connector and terminals in good condition?

YES : Go to Step 6.
NO : Repair or replace the damaged components. Refer to

GROUP 00E, Harness Connector Inspection

P.00E-2

.

AC204750

CONNECTOR : D-13

AB

PCM

1
3 4

2

AC204918

D-13 HARNESS CONNECTOR :
COMPONENT SIDE

DF

1
3

4

2

AC204167

CONNECTOR : A-03

AT

A-03 (B)

6

12

5

3 4

2

1

9 10

8

7

11