Mitsubishi Galant. Manual — part 435

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-207

STEP 3. Using scan tool MB991502, check data list item 52:
Amount of Torque Converter Clutch Slippage. (Second
check)
(1) Connect scan tool MB991502 to the data link connector.
(2) Start the engine and run at constant speed of 50km/h

(31mph). (Gear range: 3rd gear)

(3) Set scan tool MB991502 to data reading mode for item 52:

Amount of Torque Converter Clutch Slippage.

•

Driving at constant speed of 50km/h (31mph), the
display should be "

−

10 to 10 r/min."

•

The display should be "

−

300 to

−

100 r/min" or "100 to

300 r/min" when the accelerator pedal is released (50
km/h (31 mph) and less).

(4) Turn the ignition switch to "LOCK" (OFF) position.

Q: Is the sensor operating properly?

YES : This malfunction is intermittent. Refer to GROUP 00,

How to Use Troubleshooting/Inspection Service
Points

−

How to Cope with Intermittent Malfunction

P.00-8

.

NO : Go to Step 4.

STEP 4. Replace the valve body.
(1) Replace the valve body. Refer to GROUP 23B, Transaxle

P.23B-10

.

(2) Carry out a test drive.
(3) Read in the A/T diagnostic trouble code.

Q: Is the A/T diagnostic trouble code "53" is output?

YES : Go to Step 5.
NO : The inspection is complete.

STEP 5. Replace the PCM.
(1) Replace the PCM.
(2) Carry out a test drive.
(3) Read in the A/T diagnostic trouble code (DTC).

Q: Is the A/T diagnostic trouble code "53" is output?

YES : Replace the Torque Converter. Refer to GROUP 23B,

Transaxle

P.23B-10

.

NO : The inspection is complete.

AC003081AC

MB991502

DATA LINK
CONNECTOR

AC001860 AB

VALVE
BODY
ASSEMBLY

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-208

DTC 54: A/T Control Relay System

AC004620

A/T Control Relay System Circuit

AB

AC004286 AC

A/T CONTROL
RELAY

BATTERY

CONNECTOR: A-19X

AC004287AB

CONNECTOR: C-04

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-209

CIRCUIT OPERATION

•

A/T control relay (terminal number 1) receives the
battery positive voltage from the battery.

•

When turning the ignition switch to the "ON," the
PCM receives battery voltage from the ignition
switch (terminal 98). Then the PCM (terminal
number 50) applies a voltage to the A/T control
relay (terminal number 4), and the A/T control
relay switch is turned on. When the A/T control
relay switch is turned on, the battery applies a
power supply voltage to the PCM (terminal
numbers 77 and 89).

DTC SET CONDITIONS
If the A/T control relay voltage is less than 7 volts
after the ignition switch has been turned to the "ON,"
it is judged that there is an open circuit or a short-
circuit in the A/T control relay ground and diagnostic
trouble code number "54" is output. The transmission
is locked into the 3rd gear as a fail-safe measure.

TROUBLESHOOTING HINTS (The most likely

causes for this code to be set:)

•

Malfunction of the A/T control relay

•

Damaged harness, connector

•

Malfunction of the PCM

DIAGNOSIS

Required Special Tool:
MB991502: Scan Tool (MUT-II)

STEP 1. Using scan tool MB991502, check data list item 54:
A/T Control Relay Output Voltage.

CAUTION

To prevent damage to scan tool MB991502, always turn the
ignition switch to "LOCK" (OFF) position before
connecting or disconnecting scan tool MB991502.
(1) Connect scan tool MB991502 to the data link connector.
(2) Turn the ignition switch to "ON" position.
(3) Set scan tool MB991502 to data reading mode for item 54:

A/T Control Relay Output Voltage.

•

Voltage should be battery positive voltage.

(4) Turn the ignition switch to "LOCK" (OFF) position.

Q: Is the relay operating properly?

YES : This malfunction is intermittent. Refer to GROUP 00,

How to Use Troubleshooting/Inspection Service
Points

−

How to Cope with Intermittent Malfunction

P.00-8

.

NO : Go to Step 2.

AC004197

PCM

C-40

C-41

CONNECTORS: C-40, C-41

AB

AC003081AC

MB991502

DATA LINK
CONNECTOR

AUTOMATIC TRANSAXLE DIAGNOSIS

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AUTOMATIC TRANSAXLE

23A-210

STEP 2. Check the A/T control relay.
(1) Remove the A/T control relay A-19X.

(2) Use jumper wires to terminal 2 of A/T control relay

connector A-19X to the negative battery terminal, and
terminal number 4 of A/T control relay connector A-19X to
the positive battery terminal.

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

control relay connector A-19X.

•

Should be than 2 ohm when the jumper wire connected.

•

Open circuit when the jumper wire disconnected.

Q: Is the resistance normal?

YES : Go to Step 3.
NO : Replace the A/T control relay.

STEP 3. Check connector A-19X at A/T control relay for
damage.
Q: Is the connector in good condition?

YES : Go to Step 4.
NO : Repair or replace it. Refer to GROUP 00E, Harness

Connector Inspection

P.00E-2

.

AC004286 AC

A/T CONTROL
RELAY

BATTERY

CONNECTOR: A-19X

ACX01205

HARNESS
CONNECTOR: A-19X

AD

AC004286 AC

A/T CONTROL
RELAY

BATTERY

CONNECTOR: A-19X