Mitsubishi Galant (2004+). Manual - part 1441

BATTERY

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CHASSIS ELECTRICAL

54A-7

BATTERY TEST

M1541001200528

BATTERY TESTING PROCEDURE

STEP 1. Check the battery cables.

Remove the negative cable, then the positive cable.
Check for dirty or corroded connections.

Q: Are the battery cables dirty or have corroded 

connections?

YES : 

Clean the battery cables. Then go to Step 2.

NO : 

Go to Step 2.

STEP 2. Check the battery post.

Check for loose battery post.

Q: Are the battery posts faulty? 

YES : 

Replace the battery. Then go to Step 4.

NO : 

Go to Step 3.

STEP 3. Check the battery case and cover.
(1) Remove the hold-downs and shields.
(2) Check for broken/cracked case or cover.

Q: Is the battery case or cover faulty?

YES : 

Replace the battery. Then go to Step 4.

NO : 

Go to Step 4.

STEP 4. Check the open circuit voltage.
(1) Turn headlights on for 15 seconds.
(2) Turn headlights off for two minutes to allow 

battery positive voltage to stabilize.

(3) Disconnect the battery cables.
(4) Read open circuit voltage.

Q: Is open circuit voltage 12.4 volts or more?

YES : 

Go to Step 5.

NO : 

Charge the battery at 5 amps for 10.4 hours. 
Then re-test.

STEP 5. Check the load test.
(1) Connect a load tester to the battery.
(2) Load the battery at the recommended discharge 

rate (See LOAD TEST RATE CHART) for 15 
seconds.

(3) Read voltage after 15 seconds, then remove 

load.

(4) Compare the measured value with the minimum 

voltage (See LOAD TEST CHART).

Q: Is the voltage higher than minimum voltage?

YES : 

The battery is normal.

NO : 

Replace the battery. Then go to Step 4.

IGNITION SWITCH

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CHASSIS ELECTRICAL

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LOAD TEST RATE CHART

LOAD TEST CHART

IGNITION SWITCH

GENERAL DESCRIPTION

M1543000100331

IGNITION KEY REMINDER TONE ALARM

.

The ignition key reminder tone alarm will sound 
under the following condition, and warn the driver to 
remove the ignition key.

• The driver's door is opened when the ignition 

switch is at "LOCK" (OFF) or "ACC" position with-
out removing the ignition key.

However, the light reminder tone alarm will take pre-
cedence over this function.

DOOR LOCK PREVENTION FUNCTION

.

If the key is left in the ignition switch while the driver’s 
door opened or the assistant door opened, all door 
are automatically unlock to prevent locking the igni-
tion key in the vehicle after door is locked.

IMMOBILIZER SYSTEM

.

The immobilizer system consists of the ignition key, 
the key ring antenna, immobilizer-ECU, and the 
PCM. The ignition key has a built-in transponder. The 
key ring antenna is installed on the steering lock key 
cylinder. Only the registered ignition key permits the 
engine to start, therefore, the engine can never be 
started by means of a forged key or by connecting 
the ignition wiring directly. The system is significantly 
safe and reliable against theft. In addition, the driver 
has only to turn the ignition switch to the "ON" posi-
tion to activate the immobilizer system. If the require-

ments for starting the engine are not satisfied, the 
engine will be immobilized. If a registered ignition key 
is lost, all your ignition keys need to be registered 
again using scan tool MB991958 (MUT-III Sub 
Assembly) to ensure security (Refer to 

P.54A-40

). 

An additional ignition key can be registered as fol-
lows (only if no ignition keys are lost):

• Using scan tool MB991958 (MUT-III Sub Assem-

bly) (Refer to 

P.54A-40

).

• By operating two ignition keys that have been 

already registered (Refer to 

P.54A-40

).

.

OPERATION
1. When the ignition switch is turned to "ON" 

position, the PCM sends a requirement for the 
encrypted code to the immobilizer-ECU (at this 
time, the engine is remobilized).

2. When the immobilizer-ECU receives the 

requirement from the PCM, the immobilizer-ECU 
supplies power to the transponder inside the 
ignition key via the antenna. The energized 
transponder sends the encrypted code back to the 
immobilizer-ECU via the antenna.

3. The immobilizer-ECU judges the encrypted code 

with its code logic in itself. If they are identical, the 
immobilizer-ECU sends the encrypted code to the 
PCM.

4. If the PCM can not receive the encrypted code, 

the engine will be immobilized.

Load test

252 amps

Cranking ratio (0

°F)

525 amps

550 amps

Reserve capacity

90 minutes

115 minutes

Application

BCI Group size 86

BCI Group size 24

TEMPERATURE 

°C 

(

°F)

21 (70) 
AND 
ABOVE

16 (60)

10 (50)

4 (40)

−1 (30)

−7 (20)

−12 (10) −18 (0)

Minimum voltage

9.6

9.5

9.4

9.3

9.1

8.9

8.7

8.5

IGNITION SWITCH

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CHASSIS ELECTRICAL

54A-9

CAUTION WHEN REPLACING IMMOBILIZER SYSTEM RELATED PARTS
To replace immobilizer system related parts, refer to the table below. When the ignition key is re-registered 
with scan tool MB991958, the originally registered ignition key registration information will be lost.

IGNITION KEY REMINDER TONE ALARM AND DOOR LOCK PREVENTION FUNCTION 
DIAGNOSIS

M1543000701046

The Ignition key reminder tone alarms and door lock 
prevention function are controlled by the Simplified 
Wiring System (SWS). For troubleshooting, refer to 
GROUP 54B, SWS Diagnosis 

P.54B-59

.

AC306415AB

TRANS-
PONDER

POWER
(WIRELESS)

ENCRYPTED
CODE (WIRELESS)

MUT-III

POWERTRAIN
CONTROL 
MODULE

CONTROL 
SIGNAL

IGNITION
KEY RING
ANTENNA

IMMOBILIZER- 
ECU

ITEMS

PCM

IMMOBILIZER-ECU

IGNITION KEY

When replacing PCM

-

Replacement is not 
required

Replacement is not required. 
Re-registration are required.

When rewriting PCM

-

Replacement is not 
required

Replacement is not required. 
Re-registration is not required.

When replacing 
immobilizer-ECU

Replacement not 
required

-

Replacement is not required. 
Re-registration is required.

When adding ignition keys 
newly (if registered ignition 
keys are not lost)

Replacement not 
required

Replacement is not 
required

Register only additional ignition 
keys to be registered.

When adding ignition key 
newly (if registered ignition 
keys are lost)

Replacement not 
required

Replacement is not 
required

Register ignition key to be 
added and re-register all other 
ignition keys.

When ignition key is lost

Replacement not 
required

Replacement is not 
required

Re-register all other ignition 
keys except the lost one.

IGNITION SWITCH

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CHASSIS ELECTRICAL

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IMMOBILIZER SYSTEM DIAGNOSIS

INTRODUCTION TO IMMOBILIZER SYSTEM DIAGNOSIS

M1543009901326

CAUTION

The encrypted code should always be re-regis-
tered when replacing the immobilizer-ECU.
The immobilizer system consists of the immobi-
lizer-ECU, PCM, ignition key and ignition key ring 
antenna. If the engine cannot be started by using a 
registered ignition key, one of these components 
may be defective. If the immobilizer system has 
immobilized the engine, MFI system DTC P0513 will 
be output. In this case, observe the immobilizer sys-
tem troubleshooting.

IMMOBILIZER SYSTEM DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1543006900670

Use the following steps to plan your diagnostic strat-
egy.
1. Gather information about the problem from the 

customer.

2. Verify that the condition as described by the 

customer exists.

3. Check the vehicle for any immobilizer system 

DTCs.

4. If you cannot verify the condition and there are no 

immobilizer system DTCs, the malfunction is 
intermittent. Refer to GROUP 00, How to Use 
Troubleshooting/inspection Service Points 

− How 

to Cope with Intermittent Malfunctions 

P.00-6

.

5. If you can verify the condition but there are no 

immobilizer system DTCs, or the system cannot 
communicate with scan tool MB991958, refer to 
Symptom Chart and find the fault 

P.54A-18

.

6. If there is an immobilizer system DTC, record the 

DTC, then erase it from the memory using scan 
tool MB991958.

7. Recreate the immobilizer system DTC set 

conditions to see if the same immobilizer system 
DTC will resets.
(1) If the same immobilizer system DTC resets, 

perform the appropriate diagnostic procedure. 
Refer to Diagnostic Trouble Code Chart 

P.54A-13

.

(2) If the same immobilizer system DTC does not 

reset, the malfunction is intermittent. Refer to 
GROUP 00, How to Use 
Troubleshooting/inspection Service Points 

− 

How to Cope with Intermittent Malfunctions 

P.00-6

.