
The mode control
actuator mounted on heater unit adjusts position of mode door by operating
Direction Motor based on signal of A/C control unit. Pressing mode select
switch makes the mode control actuator shift in order of vent→ B/L → floor
→ mix.
The ECM sets DTC B1250
if there is a short to power in the DR Direction actuator signal
harness.
Item
|
Detecting
Condition
|
Possible Cause
|
DTC
Strategy
|
|
•
|
Open circuit in
harness |
•
|
Short circuit in
harness |
•
|
Faulty DR Direction
actuator | |
Threshold
value
|
|
Detecting
time
|
|
FAIL
SAFE
|
•
|
Setting mode : VENT Fix at VENT
position |
•
|
Setting mode : Except VENT Fix at DEF
position | |
※ Voltage value of
Direction potentiometer as a function of position of mode
switch
Door position
|
Voltage
|
Error Detecting
Condition
|
VENT
|
0.3±0.15V
|
Undervoltage : 0.08V or less
|
DEF
|
4.7±0.15V
|
Overvoltage : 4.9V or
more
|

1. |
Connect scantool to Data Link
Connector(DLC). |
2. |
Warm up the engine to normal operating
temperature. |
3. |
Monitor DTC(Diagnostics Trouble Code) on the
scantool.

|
4. |
Is the same DTC displayed again?

|
▶ Go to "
Inspection/Repair " procedure .
|

|
▶ Fault is
intermittent caused by poor contact in the sensor's and/or
A/C-ECM connector or was repaired and A/C-ECM memory was not
cleared. Thoroughly check connectors for looseness,
poorconnection, bending, corrosion, contamination,
deterioration, or damage. Repair or replace as necessary and
go to "Verification of vehicle Repair"
procedure.
|
|
1. |
Many malfunctions in the electrical system are
caused by poor harness and terminals. Faults can also be caused by
interference from other electrical systems, and mechanical or
chemical damage. |
2. |
Thoroughly check connectors for looseness,
poor connection, bending, corrosion, contamination, deterioration,or
damage. |
3. |
Has a problem been found?

|
▶ Repair as
necessary and go to "Verification of Vehicle Repair"
procedure
|

|
▶ Go to
"Signal circuit Short Inspection"
procedure.
|
|
Signal Circuit Short
Inspection |
2. |
A/C-ECU : Connect, Driver Direction actuator :
Disconnect. |
3. |
Measure resistance between Signal(F/B)
terminal of Driver Direction actuator harness connector and and
Sensor ground terminal of Driver Direction actuator harness
connector.
|
4. |
Is "resistance" display near the specified
value?

|
▶ Go to "
Component inspection " procedure .
|

|
▶ Check for
short in harness. ▶ Repair as
necessary and then go to "Verification of Vehicle Repair"
procedure.
|
|
Check Driver air mix
actuator |
2. |
A/C-ECU, Driver Direction actuator :
Disconnect. |
3. |
Connect (+) terminal of battery to WARM(+) of
Driver Direction actuator and (-) terminal to COOL(-) .(Component
side) |
4. |
Verify that the temperature actuator operates
to the DEF position |
5. |
Verify that the temperature actuator operates
to the VENT position with reverse connecting.( DEF(+) and VENT(-) )
.(Component side)
Specification
: Refer the specifications in
fig.1
|
Actuator harness
|
DEF
(+)
|
VENT
(-)
|
Door
position
|
Battery terminal
|
12
V
|
ground
|
VENT.Mode
|
ground
|
12
V
|
DEF.Mode
|
※ Function of the actuator motor according to
terminal connection type. (observe safety
regulations) |
6. |
Is "Door position" display near the specified
value?

|
▶ Go to
"Check potentiometer" procedure.
|

|
▶
Substitute with a known-good Driver air mix actuator and check
for proper operation. If the problem is corrected, replace
Driver air mix actuator and then go to "Verification of
Vehicle Repair"
procedure.
|
|
Check potentiometer
2. |
A/C-ECU : Connect, Driver air mix actuator :
Disconnect. |
3. |
Ignition "ON"(ENGINE
"OFF"). |
4. |
Measure voltage between Signal(F/B) terminal
of Driver air mix actuator harness connector and and chassis ground
.(Component side)
Specification
: Refer the specifications in
fig.2
|
Door
position
|
Voltage
|
Error Detecting
Condition
|
VENT
|
0.3±0.15V
|
Undervoltage : 0.08V or less
|
DEF
|
4.7±0.15V
|
Overvoltage : 4.9V or
more
|
※ Voltage value of Air Mix potentiometer as a
function of temp door position. |
5. |
Is "voltage" display near the specified
value?

|
▶ Check
connectors for looseness, poor connection, bending, corrosion,
contamination, deterioration, or damage. Repair or replace as
necessary and then go to "Verification of Vehicle Repair"
procedure.
|

|
▶
Substitute with a known-good Driver Direction actuator and
check for proper operation. If the problem is corrected,
replace Driver air Direction actuator and then go to
"Verification of Vehicle Repair"
procedure.
|
|
Verification Of Vehicle
Repair |
After a repair, it is
essential to verifying that the fault has been corrected.
1. |
Connect scan tool and select "Diagnostic
Trouble Codes(DTCs)" mode. |
2. |
Using scantool, Clear
DTC. |
3. |
Operate the vehicle within DTC Enable
conditions in General information. |
4. |
Are any DTCs present?

|
▶ Go to the
applicable troubleshooting procedure.
|

|
▶ System is
performing to specification at this
time.
|
|