2004 MITSUBISHI ENDEAVOR ignition

If DTC B1021 or B1022 is stored as a past trouble, carry out diagnosis with
particular emphasis on wiring and connector(s) between the A/C-ECU and the
air thermo sensor. 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 air thermo sensor. Malfunction of the A/C-ECU.
DIAGNOSIS REQUIRED SPECIAL TOOL:

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 connector.
2. Turn the ignition switch to "ON" position.
3. Dia
gnose the CAN bus line.

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

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.
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. Using scan tool MB991958, check data list item 03: air thermo
sensor.

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

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.
2. Ignition switch: ON
3. Check the data list.
Item 03: air thermo sensor.
Check that the passenger room temperature matches the displayed
value on the scan tool while the engine is cold.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?

YES:
Replace the A/C-ECU. Then go to Step 7 .
NO:
Go to Step 4.
STEP 4. Check A/C-ECU connectors C-16, C-17 and air thermo sensor
connector C-122 for loose, corroded or damaged terminals, or terminals
pushed back in the connector.

Q: Are A/C-ECU connectors C-16, C-17 and air thermo sensor connector
C-122 in good condition?

YES:
Go to Step 5.
NO:
Repair or replace the connector. Refer to
HARNESS
CONNECTOR INSPECTION
. Then
go to Ste
p 7 .
NOTE: When this DTC is set and the system is fail-safe
status, the value of service data displays -6°C.

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 .
Code No. B1031, B1032 A/C Pressure Sensor System Fig. 38: View A/C Pressure Sensor Circuit

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

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. Using scan tool MB991958, check data list item 04: A/C pressure
sensor.

1. Connect scan tool MB991958 to the data link connector.
2. Assemble a manifold gauge onto the high pressure service valve.
3. Turn ON the engine and then turn ON the air conditioner switch.
4. Check the data list.
Item 04: A/C pressure sensor. Check that the refrigerant pressure matches the displayed value on the
scan tool.
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?

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

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.
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 B1041, B1042: AIR MIXING DAMPER CONTROL MOTOR AND POTENTIOMETER (POTENTIOMETER
SYSTEM) Fig. 53: View Of Air Mixing Damper Control Motor And Potentiometer Circuit

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.

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

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.
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. Using scan tool MB991958, check data list item 10: air mix
potentiometer.

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

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.
2. Start the engine.
3. Check the data list.
Item 10: air mix potentiometer.
Check that the set position of the heater control matches the displayed
position on the scan tool.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?

YES:
Replace the A/C-ECU. Then go to Step 7 .
NO:
Go to Step 4.
STEP 4. Check A/C-ECU connectors C-16, C-17 and air mixing damper
control motor and potentiometer connector C-109 for loose, corroded or
damaged terminals, or terminals pushed back in the connector.

Q: Are A/C-ECU connectors C-16, C-17 and air mixing damper control
motor and potentiometer connector C-109 in good condition?

YES:
Go to Step 5.
NO:
Repair or replace the connector. Refer to
HARNESS
CONNECTOR INSPECTION
. Then
go to Ste
p 7 .

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