module MITSUBISHI ENDEAVOR 2004 Service Repair Manual

4.
STEP 4. Recheck for diagnostic trouble code.

Check again if the DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES:
A poor connection, open circuit or other intermittent malfunction is
present in the lines between the powertrain control module and the A/C-
ECU (Refer to
HARNESS CONNECTOR INSPECTION
).
NO:
Replace the powertrain control module. On completion, check that
the DTC is not reset.

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

5.
STEP 5. Recheck for diagnostic trouble code.

Check again if the DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES:
A poor connection, open circuit or other intermittent malfunction is
present in the lines between the powertrain control module and the A/C-
ECU (Refer to
HARNESS CONNECTOR INSPECTION
).

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

DTC U1120: FAILURE INFORMATION ON POWERTRAIN CONTROL MODULE (RELATED TO ENGINE)TROUBLE JUDGMENT The A/C-ECU receives engine control system-related signal from the powertrain
control module by the CAN bus lines. If a fail-safe related data is contained in the
signal from the powertrain control module, DTC U1120 will be stored. TECHNICAL DESCRIPTION (COMMENT)
CURRENT TROUBLE
The wiring harness wire or connectors may have loose, corroded, or damage
terminals, or terminals pushed back in the connector, the powertrain control
module, or the A/C-ECU may be defective.
PAST TROUBLE
If DTC U1120 is stored as a past trouble, carry out diagnosis with particular
emphasis on wiring and connector(s) in the CAN bus line between the A/C-
ECU and the powertrain control module, and the power supply system to the
powertrain control module. If the connectors and wiring are normal, and
obviously the ECU is the cause of the trouble, replace the ECU. If in doubt, do
not replace the ECU.
CAUTION: If DTC U1120 is set in the A/C-ECU, diagnose the
CAN main bus line.
CAUTION: Whenever the ECU is replaced, ensure that the
communication circuit is normal.
CAUTION: The engine control system- related DTC may be set
when DTC U1120 is set (For details refer to
INTERSYSTEM AFFILIATED DTC REFERENCE
TABLE
). Diagnose the engine control system first
when the engine control system- related DTC is set.
NOTE: For a past trouble, you cannot find it by the scan tool CAN
bus diagnostics even if there is a failure in CAN bus lines.

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

TROUBLESHOOTING HINTS
Malfunction of the A/C-ECU. Malfunction of the powertrain control module.
DIAGNOSIS REQUIRED SPECIAL TOOLS:

MB991223: Harness Set MB991958: Scan Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.) MB991827: MUT-III USB Cable MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

1. Connect scan tool MB991958 to the data link connec
tor.
In this case, refer to HOW TO USE TROUBLESHOOTING/ INSPECTION SERVICE POINTS
). and check the CAN bus
lines. You can narrow down the possible cause of the
trouble by referring to the DTC, which is set regarding the
CAN communication-linked ECUs (Refer to EXPLANATION
ABOUT THE MUT
-III CAN BUS DIAGNOSIS
).
CAUTION: To prevent damage to scan tool (MUT-III), always
turn the ignition switch to the "LOCK" (OFF)
position before connecting or disconnecting
scan tool (MUT-III).

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the CAN bus line found to be normal?

YES:
Go to Step 2.
NO:
Repair the CAN bus line (Refer to
EXPLANATION ABOUT THE
MUT
-III CAN BUS DIAGNOSIS
, DIAGNOSIS < VEHICLES
WITHOUT ADVANCED AIR BAG
or
DIAGNOSIS WITH ADVANCED AIR BAG>
.)
STEP 2. Using scan tool MB991958, read the powertrain control module
diagnostic trouble code.

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

Check again if the DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory?

YES:
There is an intermittent malfunction such as poor engaged connector
(s) or open circuit (Refer to
HOW TO USE TROUBLESHOOTING/
INSPECTION SERVICE POINTS
).
NO:
Replace the powertrain control module. On completion, check that
the DTC is not reset.
STEP 5. Recheck for diagnostic trouble code.


2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

Check again if the DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the check result satisfactory?

YES:
A poor connection, open circuit or other intermittent malfunction is
present in the lines between the powertrain control module and the A/C-
ECU (Refer to
HOW TO USE TROUBLESHOOTING/ INSPECTION
SERVICE POINTS
).
NO:
Replace the A/C-ECU. On completion, check that the DTC is not
reset.
SYMPTOM CHART
CAUTION: During diagnosis, a DTC code associated with other
system may be set when the ignition switch is turned
on with connector(s) disconnected. On completion,
confirm all systems for DTC code(s). If DTC code(s)
are set, erase them all.

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

Fig. 133: Checking A/C Compressor Clutch Relay For Continuity

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Fig. 134: A/C Compressor Clutch Relay

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

Q: Is the A/C compressor clutch relay in good condition?

YES:
Go to Step 7.
NO:
Replace the A/C compressor clutch relay. Check that the air
conditioning works normally.
STEP 7. Check powertrain control module connector B-20 and A/C
compressor assembly B-114 for loose, corroded or damaged terminals, or
terminals pushed back in the connector.

Q: Are powertrain control module connector B-20 and A/C compressor
assembly B-114 in good condition?

YES:
Go to Step 8.
NO:
Repair or replace the connector. Refer to
HARNESS
CONNECTOR INSPECTION
. Check that the air conditionin
g works

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

Fig. 137: Locating Connector B
-114

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

2. Disconnect powertrain control module connector B-20 and ground harness
side terminal No.81.
3. Turn the i
gnition switch to the "ON"
position.

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

Fig. 152: Locating Connectors B
-16X And B
-114

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

STEP 14. Check the wiring harness between powertrain control module
connector B-20 (terminal 81) and A/C compressor clutch relay connector
B-16X (terminal 3).

Q: Is the wiring harness between powertrain control module connector B-
20 (terminal 81) and A/C compressor clutch relay connector B-16X
(terminal 3) in good condition?

YES:
It can be assumed that this malfunction is intermittent.
Refer to
HOW TO USE TROUBLESHOOTING/ INSPECTION
SERVICE POINTS
.
NO:
Re
pair the wirin
g harness. Check that the air con
ditionin
g works

2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor