Daewoo Musso. Manual - part 361

9W-6  IMMOBILIZER SYSTEM

IMMOBILIZER SYSTEM  9W-7

System Integration

The med 98.2 immobilizer is an anti-theft protection device allowing the start of the engine only if a specific authorization
is obtained during the start up phase. The med 98.2 will allow (prohibit) the start of the engine by driving ON (OFF) an
internal solenoid valve.

The med 98.2 is a single unit integrating the following subsystem :

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a valve that allows (valve open) or blocks (valve closed) the fuel flow through the engine fuel system

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a microprocessor control system to control and activate the valve during the start up of the engine, in order to
allow the start up only when a specific permission is given

the med 98.2 task is, therefore, to prevent the non authorized start up of the engine.

The functional unit includes also a basic set of electronic components whose function is to reduce its dependence on
the microprocessor control system: a part from a short temporarily period, during the start up phase, the electronics
allows the control system to excite and open the valve, but it doesn’t allow to close it.

The valve can be shut off only after the KL 15 has been deactivated.

The structure allows to obtain the highest degree of safe-operation (functionality fail-start): a failure in the
microprocessor unit cannot cause the shut-off of the valve. The main consequence of this type of failure is to prevent
the next engine start up.

As a result of the above considerations, the med 98.2 immobilizer can realize its anti-theft functionality only in conjunction
with a control device: the ICU.

The ICU, when requested, sends a coded message to med 98.2 according to a settled communication protocol. The
med 98.2 will allow the start of the engine based upon this message.

In addition to the basic anti-theft functionality, the 98.2 immobilizer provides a number of diagnostic services when it
is connected to an external test instrument (SCAN-100). Those connections are depicted in the following integration
diagram (Fig. 1), where the dashed line indicates a temporary link for diagnostic purposes, and the shaded area the
med 98.2 system’s physical boundaries:

Fig. 1 - System Integration

Explanation of symbols:

med 98.2

Immobilizer

ICU

Immobilizer Control Unit

TESTER

Device that can be connected for diagnostic purposes

K-LINE

Serial line for communication with ICU

KL15

Ignition key (Power supply for med 98.2)

GND

Ground

9W-8  IMMOBILIZER SYSTEM

Defects

Possible cause

Remedy

No communication with
transponder

1. Defective wiring harness

-

Power supply/Open/short of ground

-

Open/short of signal terminal or

mis-conneting(between ECU

terminal No. 13 and 14)

1. Connect/replace the wire correctly.

2.1 Replace the transponder

2.2 Immobilizer programming

2. Damaged transponder

3. Replace the antenna

3. Defective antenna

4.1 Replace the ECU

4.2 Replace all transponder of the keys

4.3 Immobilizer programming

4. Defective ECU

No immobilizer
programming
(Components and
wiring harnesses are
normal but codes in
ECU and transponders
are not registered
normally)

1. Replace the transponders and ECU

with new

; Immobilizer programming is not

performed

1. Perform immobilizer programming

2. Replace transponders only(new)

; Immobilizer programming is not

performed

2. Perform immobilizer programming

3. Replace ECU only(new)

3.1 Replace the transponders with new

3.2 Perform immobilizer programming

4. Replace the transponder only

; Programmed for other ECU

4.1 Replace the transponders with new

4.2 Perform immobilizer programming

5. Re-programming is not performed

after clearing transponder code stored

in ECU that normally used system

5. Immobilizer programming

Notice

1. Application of ex-programmed transponder into other ECUs.

; In this case, it can not be removed for the settled “lock bit” in transponder even though you perform immobilizer

problem normally. Moreover it is impossible to start engine, so replace the transponder with new and perform
immobilizer programming.

DIAGNOSIS

GASOLINE ENGINE

Cause and Remedy for Defective When Diagnosed by Scanner

IMMOBILIZER SYSTEM  9W-9

Check and Remedy when Engine Does not Start

Starter operates normally?

Yes

No

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Check fuses (No. 8 and 27)

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Check ECU and antenna power

ECU terminal

- No. 12 (Power)

- No. 11 (Ignition)

- No.5/10 (Ground)

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Check battery voltage

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Check battery wiring

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Check signal wires between ECU

and antenna

-

Immobilizer No.3 wire (0.5BY) =

ECU No. 14 pin (0.75BW)

: Writing immobilizer code number

-

Immobilizer No.4 wire (0.5Y) =

ECU No.13  pin (0.75Y)

: Reading immobilizer cod number

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Check starter wires

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Check TCU wires (only for 5-

speed automatic transmission)

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Check starter and TCU

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ECU No.2 pin : check normal
signal of the starter 

1)

- Engine cranking voltage : 8-15V

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Check engine speed sensor wires

and replace

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Replace immobilizer antenna

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Replace transponder and ECU

Notice

1)

MSE ECU equipped vehicle is designed to
make fuel injection when the engine speed
for initial cranking is over 450rpm if there
are no start switch inputs in ECU No. 2 pin.

If transponder and ECU are replaced,
perform programming.