1997 MITSUBISHI TRITON immobilizer

MPI ± Troubleshooting13A-43
INSPECTION PROCEDURE 28
Power steering fluid pressure switch system
Probable cause
The presence or absence of power steering load is input to the engine-ECU.
The engine-ECU controls the idle speed control (ISC) servo based on this input.
Malfunction of power steering fluid pressure switch

Improper connector contact, open circuit or
short-circuited harness wire

Malfunction of the engine-ECU
Check the power steering fluid pressure switch.
(Refer to GROUP 37A ± On-vehicle Service.)NG
Replace
OK
Measure at the power steering fluid pressure switch connector
A-74.

Disconnect the connector, and measure at the harness side.

Voltage between 1 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connector. C-50NG
Repair
OK
Check trouble symptom.
NG
Check harness wire be-
tween engine-ECU and
power steering fluid pres-
sure switch connector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following
connector. A-74NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 29
A/C switch and A/C relay system
Probable cause
When an A/C ON signal is input to the engine-ECU, the engine-ECU carries out
control of the idle speed control (ISC) servo, and also operates the A/C compressor
magnetic clutch.
Malfunction of A/C control system

Malfunction of A/C switch

Improper connector contact, open circuit or
short-circuited harness wire

Malfunction of the engine-ECU
Check the A/C compressor relay.
(Refer to GROUP 55 ± On-vehicle Service.)NG
Replace
OK
Measure at the engine-ECU connectors C-49, C-50.

Disconnect the connector, and measure at the harness side.


Voltage between 22 and earth, and 45 and earth
(Ignition switch: ON, A/C switch: ON)
OK:System voltage

Short circuit between 22 and earth
(Ignition switch: ON, A/C switch: ON)
OK:A/C compressor clutch turns on.


Voltage between 8 and earth, and 45 and earth
(Ignition switch: ON, A/C switch: ON)
OK:System voltage

Short circuit between 8 and earth
(Ignition switch: ON, A/C switch: ON)
OK:A/C compressor clutch turns on.NGCheck the A/C system. (Refer to GROUP 55 ± On-vehicle Service.)
OKCheck the following
connectors. C-49, C-50NG
Replace
OK
Check trouble symptom.
NG
Replace the engine-ECU.

MPI ± Troubleshooting13A-44
INSPECTION PROCEDURE 30
Ignition circuit system
Probable cause
The engine-ECU interrupts the ignition coil primary current by turning the power transistor
inside the engine-ECU ON and OFF.
Malfunction of ignition switch.

Malfunction of power transistor unit

Improper connector contact, open circuit or
short-circuited harness wire

Malfunction of the engine-ECU
NGCheck the following
connector. C-88NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between ignition coil and
ignition switch connector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
OK
Check the following
connectors. A-65, A-70NG
Repair
OK
Check trouble symptom.NGCheck ignition coil and power transistor unit system. (Refer to
P.13A-56, INSPECTION PROCEDURE 48.)
OK
Measure at the power transistor unit connector A-70.

Disconnect the connector and measure at the harness side.

Continuity between 2 and earth
OK: ContinuityNG
Check the harness wire between power transistor unit connector
and earth, and repair if necessary.
Measure at the ignition coil connector A-65.

Disconnect the connector and measure at the harness side.

Voltage between 2 and earth (Ignition switch: ON)
OK: System voltage

MPI ± Troubleshooting13A-53
INSPECTION PROCEDURE 42
Check the engine-ECU power supply and earth circuit.
OK
Check trouble symptom.
OK
Check the harness wire
between engine-ECU and
ignition switch connector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
4. NG
Check the harness wire between engine-ECU and earth, and repair
if necessary.
5. NG
OK
Check the following
connectors.
C-49, C-50, C-51NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
Check the following connectors.
A-56X, C-19, C-81, C-87NG
Repair
OK
Check trouble symptom
NG
Check the harness wire between engine-ECU and battery, and
repair if necessary.
NG
Check the harness wire between the engine-ECU and control relay,
and repair if necessary.
OK
Check trouble symptom.
2, 3. NG
Check the following
connector. C-53NG
Repair
Measure the engine-ECU connectors, C-49, C-50, C-51.

Disconnect the connector and measure at the harness side
1. Voltage between 62 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 38 and earth
OK:System voltage
3. Voltage between 12, 25 and earth (Ignition switch: ON)
OK:System voltage (when the terminal 38 is earthed)
4. Continuity between 13, 26 and earth
OK:Continuity
5. Voltage between 60 and earth
OK:System voltage1. NGCheck the following
connector. C-88NG
Repair
INSPECTION PROCEDURE 43
Check fuel pump circuit.
Measure at the fuel pump connector F-17.

Disconnect the connector and measure at the harness side.

Continuity between 2 and earth
OK:ContinuityNGCheck the following connectors.
D-02, F-17NG
Repair
OK
Check trouble symptom
NG
Check the harness wire between fuel pump and earth, and repair
if necessary.
OK
Check the following connectors. C-19, D-02, F-17NG
Repair OKCheck trouble symptom.
NG
Check the harness wire between terminal for fuel pump drive and
fuel pump connector.NG
Repair
OK
Replace the fuel pump.

MPI ± Troubleshooting13A-54
INSPECTION PROCEDURE 44
Check the fuel pump drive control circuit.
Measure at the fuel pump relay connector C-54.

Disconnect the connector and measure at the harness side.

Voltage between 4 and earth (Ignition switch: ON)
OK:System voltageNGCheck the following
connector. C-88NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between fuel pump relay
and ignition switch con-
nector.NG
Repair
OK
Check the ignition switch.
(Refer to GROUP 54 ± Ignition Switch and Immobilizer System.)
OK
Measure at the engine-ECU connector C-49.

Disconnect the connector and measure at the harness side.


Voltage between 8 and earth (Ignition switch: ON)
OK:System voltage


Voltage between 22 and earth (Ignition switch: ON)
OK:System voltageNG
Check the following
connector. C-54NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire between engine-ECU and fuel pump relay
connector, and repair if necessary.
OK
Check the following connector. C-49NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
INSPECTION PROCEDURE 45
Check air flow sensor (AFS) control circuit.
Measure at the air flow sensor connector A-77.

Disconnect the connector and measure at the harness side.
1. Voltage between 4 and earth (Ignition switch: ON)
OK:System voltage
2. Voltage between 3 and earth (Ignition switch: ON)
OK:4.8 ± 5.2 V
3. Continuity between 5 and earth
OK:Continuity1. NGCheck the harness wire between the air flow sensor and control
relay connector, and repair if necessary.
2, 3. NGCheck the following
connector. C-51NG
Repair
OK
Check trouble symptom.
NG
Check the harness wire
between the engine-ECU
and air flow sensor con-
nector.NG
Repair
OK
Replace the engine-ECU.
OK
Check the following connector. A-77NG
Repair
OK
Check trouble symptom.
NG
Replace the air flow sensor.

CHASSIS ELECTRICAL ± Ignition Switch and Immobilizer System54-8
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection Procedure 1
Communication with MUT-II is impossible.
(Communication with all systems is impossible.)
Probable cause
The cause is probably a defective power supply system (including earth) for the
diagnosis line.
Malfunction of connector

Malfunction of harness wire
Refer to GROUP 13A ± Troubleshoot-
ing.
Inspection Procedure 2
Communication with MUT-II is impossible. (Communica-
tion with the one-shot pulse input signal only is
impossible.)
Probable cause
The cause is probably a defective one-shot pulse input circuit system of the diagnosis
line.
Malfunction of connector

Malfunction of harness wire

Malfunction of ETACS-ECU
Check the harness wire between the
diagnosis connector and junction block.OKCheck the following connectors:
C-35, C-90NG
Repair
OK
Check trouble symptoms.NGReplace the ETACS-ECU.
NG
Repair
Inspection Procedure 3
Even if the driver's side door is opened, the key hole
illumination lamp does not illuminate.
Probable cause
The cause is probably a defective key hole illumination lamp circuit system or a defective
driver's side door switch input circuit system.
Malfunction of driver's side door switch

Malfunction of key hole illumination lamp

Malfunction of harness or connector

Malfunction of ETACS-ECU
Driver's side door switch input circuit
system check (Refer to Inspection Pro-
cedure 5 on P.54-9.)
OK
Key hole illumination lamp check
(Refer to P.54-22.)NG
Replace
OK
Disconnect the key reminder switch
connector C-72 and measure at the har-
ness side.

Voltage between the terminal No.1
and body earth
OK:System voltageOKCheck the following connectors:
C-72, C-86, C-91NG
Repair
OK
Check trouble symptom.
NGNG
Check the following connectors:
C-72, C-79NG
Repair
OK
Check trouble symptom.
NG
Check the harness between the key re-
minder switch and junction block, and
repair if necessary.
Check the harness between the key re-
minder switch and junction block, and
repair if necessary.OKReplace the ETACS-ECU.
NG
Repair

CHASSIS ELECTRICAL ± Ignition Switch and Immobilizer System54-9
Inspection Procedure 4
Key hole illumination lamp remains illuminated.
Probable cause
The cause is probably a short harness or a defective ETACS-ECU.
Malfunction of harness

Malfunction of ETACS-ECU
When the connector C-86 of the junction block is disconnected,
does the lamp switch off?NoCheck the harness between the key reminder switch and junction
block, and repair if necessary.
Ye s
Replace the ETACS-ECU.
Inspection Procedure 5
Driver's side door switch input circuit system check
Door switch check (Refer to GROUP
42 ± Door Assembly.)NG
Replace
OK
Door switch earth checkNG
Repair
OK
Disconnect the door switch connector
D-17 and measure at the harness side.

Voltage between the terminal No.2
and body earth
OK:5 VNGCheck the following connectors:
C-87, D-17, D-21NG
Repair
OK
Replace the ETACS-ECU.
OK
Check trouble symptom.NGCheck the harness between the door
switch and junction block, and repair
if necessary.

CHASSIS ELECTRICAL ± Ignition Switch and Immobilizer System54-10
Immobilizer System
Caution
1. The ID code should always be re-registered when replacing the immobilizer-ECU. vehicles>
2. If the immobilizer-ECU has been replaced, you will need to re-register the ignition key ID codes
and to reset the code for the fuel cut valve controller to the factory setting. vehicles>
3. If the immobilizer-ECU has been replaced with a new part, the password (vehicle secret code)
which has been stored in the immobilizer-ECU for each vehicle will be replaced by the password
(secret code) specified by the customer.
STANDARD FLOW OF DIAGNOSIS TROUBLESHOOTING54300690024
Refer to GROUP 00 ± How To Use Troubleshooting/Inspection Service Points.
DIAGNOSIS FUNCTION54300700116
DIAGNOSIS CODES CHECK
Refer to GROUP 00 ± How To Use Troubleshooting/Inspection Service Points.
ERASING DIAGNOSIS CODES
Refer to GROUP 00 ± How To Use Troubleshooting/Inspection Service Points.
Caution
The diagnosis codes which result from disconnecting the battery cables cannot be erased.
INSPECTION CHART FOR DIAGNOSIS CODES

54300710027
Diagnosis code No.Inspection itemsReference
page
11Transponder communication system or radio interference of ID code54-11
12*ID code are not the same or are not registered54-11
21Communication system between MUT-II and engine-ECU54-12
31EEPROM abnormality inside immobilizer-ECU54-12
NOTE
*: Diagnosis code No. 12 is not recorded.

CHASSIS ELECTRICAL ± Ignition Switch and Immobilizer System54-11
INSPECTION PROCEDURE FOR DIAGNOSIS CODES

Code No.11 Transponder communication system or radio
interference of ID codeProbable cause

The ID code of the transponder is not sent to the immobilizer-ECU immediately
after the ignition switch is turned to ON position.

If the engine is started while several ignition keys are in the vicinity, then interference
between the different keys may occur, which will cause this code to be generated.
Radio interference of ID code

Malfunction of transponder

Malfunction of ignition key ring antenna

Malfunction of harness or connector

Malfunction of immobilizer-ECU
Are there any other ignition keys in the
vicinity of the ignition key being used
to for starting?Ye sMove other keys well away from key
being used.
NoCheck trouble symptom.
NG
Does the engine start using the spare
ignition key which has had the ID code
registered?OKReplace the ignition key that does not
work.Re-register the ID code
(Refer to P.54-23.)
NG
Diagnosis code checkCode No.12
occurs.To INSPECTION PROCEDURE FOR
DIAGNOSIS CODE No.12.
Code No.11 occurs.
Ignition key ring antenna continuity
check (Refer to P.54-22.)NG
Replace
OK
Check the following connectors:
C-36, C-71NG
Repair
OK
Check trouble symptom.NGCheck the harness between the immobi-
lizer-ECU and key ring antenna.NG
Repair
OK
Replace the immobilizer-ECU.Register the password (secret code)
and ID code. (Refer to P.54-23.)
Code No.12 ID codes are not the same or not registered.Probable cause
The ID code which is sent from the transponder is not the same as the ID code
which is registered in the immobilizer-ECU.
The ID code in the ignition key being used has not
been properly registered.

Malfunction of immobilizer-ECU
Re-register the ID code
(Refer to P.54-23.)Check trouble symptom.NGReplace the immobilizer-ECU.
Register the password (secret code)
and ID code. (Refer to P.54-23.)