MITSUBISHI ENDEAVOR 2004 Service Repair Manual

Fig. 23: Locating Connector A
-22
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2. Measure the resistance between the sensor terminals under at least two
temperatures. The resistance values should meet the values shown.
NOTE: The temperature should be within the shown range.

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

Q: Is the ambient air temperature sensor in good condition?

YES:
Replace the A/C-ECU. Then go to Step 7.
NO:
Replace the ambient air temperature sensor. Then go to Step 7.
STEP 7. Recheck for diagnostic trouble code.

Check again if the DTC is set.
1
.Co
nnect
sca
n too
l MB
991958
to the data
link
connect
or
Fig. 24: Sensor Terminal Resistance Graph

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

Fig. 25: Connectin
g Scan Tool MB991958 To Data Link Connector

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

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA
.
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 B1021, B1022: AIR THERMO SENSOR SYSTEM
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

Fig. 26: View Of Air Thermo Sensor Circuit

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

Fig. 27: Identifying Connectors C
-16 And C
-17
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2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

Fig. 28: Identifying Connectors C
-104 And C
-122

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DTC SET CONDITION
DTC B1021 is set if there is a short circuit in the air thermo sensor input
circuit. DTC B1022 is set if there is a defective connector connection, or if there is an
open circuit in the harness.
TECHNICAL DESCRIPTION (COMMENT)
CURRENT TROUBLE
The A/C-ECU, the air thermo sensor, or connector(s) or wiring between the
two may be defective.
PAST TROUBLE
2004 Mitsubishi Endeavor LS
2004 HVAC Heater Air Conditioning, Ventilation - Endeavor

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

Fig. 29: Connecting Scan Tool MB991958 To Data Link Connector

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

Courtesy of MITSUBISHI MOTOR SALES OF AMERICA
.
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