9T–18 IMMOBILIZER ANTI-THEFT SYSTEM
DAEWOO M–150 BL2
D19T002B
DIAGNOSTIC TROUBLE CODE (DTC) 1602
ECM IMMOBILIZER ERROR (ECM LOCKED)
Circuit Description
When the ignition is turned ON, the key is tested by the
immobilizer anti-theft system. While the key code is be-
ing read by the immobilizer control unit, the engine can
start and run with any key that will turn the lock cylinder.
The key code is read and compared with key codes that
have been stored in the memory of the immobilizer con-
trol unit. If a valid key is detected, the immobilizer control
unit sends a serial data release message to the elec-
tronic control module (ECM). Included in the release
message is an identification (ID) code which assures
that neither the immobilizer control unit nor the ECM has
been substituted to defeat the system. If the ECM re-ceives an invalid release message, the ECM performs
the following actions:
Disables the fuel injector circuit.
Disables the fuel pump circuit.
Disables the ignition coil.
DTC 1602 Will Set When
The immobilizer control unit does not learn and store
the codes of valid keys.
DTC 1602 Will Clear When
The ignition switch is turned OFF or the scan tool
TROUBLE CODE CLEAR command is issued.
9T–24 IMMOBILIZER ANTI-THEFT SYSTEM
DAEWOO M–150 BL2
KEY STATUS ERRORS (FENIX 5MR)
The following KEY STATUS messages may be shown
on the scan tool after commanding FIRST KEY COD-
ING and KEY ADD:
IGNITION OFF STATUS. This message informs the
technician that the ignition is OFF during the key cod-
ing process. Turn the ignition ON during key coding,
but do not start the engine.
KEY IS OCCUPIED. Only five keys may be coded. If
a new key is desired, the previous key codes must be
deleted. Up to five keys may then be authorized.
ALREADY AUTHORIZED. Key coding is being at-
tempted with a key that is already authorized.
ERROR NO. A3, A4, A5. There is no communication
between the transponder in the ignition key and the
detection coil. Follow the steps below to diagnose the
problem:
1. Try a different key. If a different key works, the
problem is in the original key.
2. If trying a different key results in the same er-
ror message, replace the detection coil.
INVALID KEY. The communication between the im-
mobilizer control unit and the key transponder has not
validated the key. Follow the steps below to diagnose
the problem:
1. Code the key. Refer to “Key Coding Proce-
dure” in this section.
2. If the same message is received after key
coding, check the connection of the detection
coil.
3. If the detection coil is okay, replace the immo-
bilizer. Refer to “Immobilizer Control Unit” in
this section.
NO TRANSPONDER DETECTED. The fault may be
in ignition key transponder, the detection coil, or the
immobilizer. Follow the steps below to diagnose the
problem:
1. Try a different key. If a different key works, the
problem is in the original key.
2. If trying a different key results in the same er-
ror message, check the connection of the
detection coil.
3. If the connection of the detection coil is okay,
disconnect the detection coil and use an ohm-
meter to check for an open detection coil.
4. If the detection coil is not open, replace the
immobilizer control unit. Refer to “Immobilizer
Control Unit” in this section.
KEY STATUS ERRORS (SIRIUS D3)
The following KEY STATUS messages may be shown
on the scan tool after commanding FIRST KEY COD-
ING and KEY ADD:
IGNITION OFF STATUS. This message informs the
technician that the ignition is off during the key coding
process. Turn the ignition ON during key coding, but
do not start the engine.
KEY IS OCCUPIED. Only five keys may be coded. If
a new key is desired, the previous key codes must be
deleted. Up to five keys may then be authorized.
ALREADY AUTHORIZED. Key coding is being at-
tempted with a key that is already authorized.
ERROR NO. A3, A4, A5. There is no communication
between the transponder in the ignition key and the
detection coil. Follow the steps below to diagnose the
problem:
1. Try a different key. If a different key works, the
problem was in the original key.
2. If trying a different key resulted in the same error
message, replace the detection coil.
INVALID KEY. The communication between the im-
mobilizer control unit and the key transponder has not
validated the key. Follow the steps below to diagnose
the problem:
1. Code the key. Refer to “Key Coding Procedure” in
this section.
2. If the same message is received after key coding,
check the connection of the detection coil.
3. If the detection coil is okay, replace the immobiliz-
er. Refer to “Immobilizer Control Unit” in this sec-
tion.
NO TRANSPONDER DETECTED. The fault may be
in ignition key transponder, the detection coil, or the
Immobilizer. Follow the steps below to diagnose the
problem
1. Try a different key. If a different key works, the
problem was in the original key.
2. If trying a different key resulted in the same error
message, check the connection of the detection
coil.
3. If the connection of the detection coil is okay, dis-
connect the detection coil and use an ohmmeter to
check for an open detection coil.
4. If the detection coil was not open, replace the im-
mobilizer control unit. Refer to “Immobilizer Control
Unit” in this section.
IMMOBILIZER ANTI-THEFT SYSTEM 9T–27
DAEWOO M–150 BL2
6. Turn the ignition OFF and ON again, but do not
crank or start the engine. The ECM will reset the
ECM ID code to match the new ID code that was
calculated and sent by the immobilizer control unit
when the ignition was first turned ON after the reset
command.
7. Return the system to the normal mode.
8. Turn OFF the ignition.
9. Turn ON the ignition.
10. Start the engine.
After reprogramming the ID code, the scan tool SYS-
TEM DIAGNOSIS command can verify that the ECM ID
code matches the immobilizer control unit ID code.
If the reprogramming procedure does not result in
matching ID codes, check the electrical connectors for
the serial data wire between the immobilizer control unit
and the ECM.
TRANSPONDER
Each valid ignition key has an internal transponder
which is a read /write transponder.
The transponder contains an implementation of a cryp-
to-algorithm with 96 bits of user configurable secret-key
contained in EEPROM and transmits data to the ICU by
modulating the amplitude of the electromagnetic field,
and receives data and commands in a similar way.
D105A504
DETECTION COIL
(Left–Hand Drive Shown, Right–Hand
Drive Similar)
Removal Procedure
1. Remove the steering column covers. Refer to Section
6E, Steering Wheel and Column.
D29T001
2. Remove the detection coil.
Disconnect the two-pin connector from the detec-
tion coil (1).
Pry the detection coil away from the lock cylinder
(2).
Important: If the detection coil will be replaced with a
new one, it does not matter if the key position trim ring is
damaged during removal. A new trim ring is part of the
new detection coil.
