2004 MITSUBISHI ENDEAVOR can bus

selection damper control motor and potentiometer. 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.
TROUBLESHOOTING HINT
Malfunction of connector. Malfunction of the harness. Malfunction of the mode selection damper control motor and potentiometer. Malfunction of the A/C-ECU.
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.

Use scan tool MB991958 to diagnose the CAN bus lines.
1. Connect scan tool MB991958 to the data link connec
tor.

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

2. Turn the ignition switch to "ON" position.
3. Diagnose the CAN bus line. Q: Is the check result satisfactory?

YES:
Go to Step 2.
NO:
Repair the CAN bus lines (Refer to
CAN BUS DIAGNOSTICS
TABLE
).
Then go to Step 7 .
STEP 2. Recheck for diagnostic trouble code.

Recheck if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.
Q: Is the check result satisfactory?

YES:
It can be assumed that this malfunction is intermittent.
Refer to
HOW TO USE TROUBLESHOOTING/ INSPECTION
SERVICE POINTS
.
NO:
Go to Step 3.
STEP 3. Usin
g scan tool MB991958, check actuator test item 13, 14, 15, 16,
17: Air outlet c/o dumper.

1. Connect scan tool MB991958 to the data link connec
tor
CAUTION: To prevent damage to scan tool MB991958,
always turn the ignition switch to the
"LOCK" (OFF) position before connecting or
disconnecting scan tool MB991958.

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

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

YES:
The procedure is complete.
NO:
Return to Step 1 .
DTC U1073: BUS OFF TROUBLE JUDGMENT DTC U1073 will be stored when the A/C-ECU ceases CAN communication (bus
off) and then resumes the communication when the ignition switch is turned to the
"LOCK" (OFF) position. TECHNICAL DESCRIPTION (COMMENT) The wiring harness wire or connectors may have loose, corroded, or damage
terminals, or terminals pushed back in the connector, or the A/C-ECU may be
defective. TROUBLESHOOTING HINTS
Defective connector(s) or wiring harness Malfunction of the A/C-ECU
DIAGNOSIS REQUIRED SPECIAL TOOLS:

MB991223: Harness Set
CAUTION: If DTC U1073 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.

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

MB991958: Scan Tool (MUT-III Sub Assembly)
MB991824: V.C.I. MB991827: USB Cable MB991910: Main Harness A
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

1. Connect scan tool MB991958 to the data link connec
tor.
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 lines (Refer to
PRECAUTIONS ON HOW TO
REPAIR THE CAN BUS LINE
).
STEP 2. Recheck for diagnostic trouble code.

Check again if the DTC is set.
1. Connect scan tool MB991958 to the data link connec
tor

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

2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. 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 A/C-ECU. On completion, check that the DTC is not
reset.
DTC U1100: POWERTRAIN CONTROL MODULE TIME-OUT (RELATED TO ENGINE) TROUBLE JUDGMENT The A/C-ECU receives engine control system-related signal from the powertrain
control module. If the ECU cannot receive the signal, DTC U1100 will be set. TECHNICAL DESCRIPTION (COMMENT)
CURRENT TROUBLE
Connector(s) or wiring harness in the CAN bus lines between the powertrain
control module and the A/C-ECU, the power supply system to the powertrain
control module, the powertrain control module itself, or the A/C-ECU may be
defective.
PAST TROUBLE
If DTC U1100 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 powe
rtrain
control m
odu
le, and the powe
r supp
ly syste
m to the
CAUTION: If DTC U1100 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.

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

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.
TROUBLESHOOTING HINTS
Powertrain control module failed Malfunction of the A/C-ECU Damaged harness wires and connectors
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)
1.
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.

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.
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

Fig. 99: Connecting Scan Tool MB991958 To Data Link Connector

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.

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 lines (Refer to
PRECAUTIONS ON HOW TO
REPAIR THE CAN BUS LINE
).
2.
STEP 2. Using scan tool MB991958 read the powertrain control module
diagnostic trouble code.

Check whether an engine and automatic transaxle DTCs are set or not.
1. Turn the ignition switch to the "ON" position.
2. Check for engine and automatic transaxle DTCs.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the check result satisfactory?

YES:
Go to Step 3.
NO:
Diagnose the powertrain control module (Refer to
DIAGNOSTIC
TROUBLE CODE CHART
).

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