Kia Sedona (2008 year). Manual - part 236

Fig. 73: Checking Voltage Between Terminal "4" Of A/C Control Unit And Chassis Ground
Courtesy of KIA MOTORS AMERICA, INC. 

4. Is the measured voltage within specifications? 

YES  

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. 

NO  

Substitute with a known-good A/C Control Unit and check for proper operation. 

If the problem is corrected, replace A/C Control Unit and then go to "VERIFICATION OF 
VEHICLE REPAIR" procedure. 

VERIFICATION OF VEHICLE REPAIR 

After a repair, it is essential to verify that the fault has been corrected. 

1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode and then clear DTC.  

2. Operate the vehicle and monitor the DTC on the scan tool.  

3. Are any DTCs present? 

YES  

Go to the applicable troubleshooting procedure.  

NO  

System is performing to specification at this time. 

DTC B1238 AMBIENT TEMPERATURE SENSOR OPEN (HIGH) 

 

2008 Kia Sedona EX 

2008 HVAC Blower & A/C Controls (Automatic) - Sedona

  

Microsoft 

 

Monday, May 24, 2010 3:56:08 PM

Page 66 

© 2006 Mitchell Repair Information Company, LLC. 

COMPONENT LOCATION 

Fig. 74: Identifying Ambient Temperature Sensor Component Location 
Courtesy of KIA MOTORS AMERICA, INC. 

GENERAL DESCRIPTION 

The ambient temperature senor located at the center stay of the condenser, detects ambient air temperature. It is 
a negative type thermistor whose resistance is inversely proportional to temperature. Its output is used for 
discharge temperature sensor, sensor fail-safe, temperature regulation door lock, blower motor level control, 
mix mode control and in-car humidity control. 

DTC DESCRIPTION 

The A/C controller sets DTC B1238 if there is an open circuit in ambient temp, sensor signal harness or the 
measured resistance value of sensor is more than threshold value (about 527kohms) 

DTC DETECTING CONDITION 

DTC DETECTING CONDITION CHART 

SPECIFICATION 

TEMPERATURE SPECIFICATION 

Item

Detecting Condition

Possible cause

DTC Strategy



Resistance check  



Open Circuit in harness  



Faulty ambient temp. Sensor  



Faulty A/C control unit  

Threshold value



> 527kohms  

Detecting time



0.3 sec  

FAIL SAFE



Control with the value of 20°C (67°F) 

Temperature [°C (°F)]

Resistance (kohms)

Temperature [°C (°F)]

Resistance (kohms)

-30 (-22)

527.99

25 (77)

30

-15 (5)

218.21

35 (95)

19.6

 

2008 Kia Sedona EX 

2008 HVAC Blower & A/C Controls (Automatic) - Sedona

  

Microsoft 

 

Monday, May 24, 2010 3:56:08 PM

Page 67 

© 2006 Mitchell Repair Information Company, LLC. 

MONITOR SCAN TOOL DATA 

1. Connect scan tool to Data Link Connector (DLC).  

2. Engine "ON"  

3. Monitor the "AMBIENT TEMP. SENSOR" Parameter on the scan tool. 

Parameter of "AMBIENT TEMP. SENSOR" will be fixed at 20°C (67°F), if there is any fault in 
AMBIENT TEMP. SENSOR. 

Fig. 75: Diagnosis Function Screen Display - Ambient Air Temp. Sensor 
Courtesy of KIA MOTORS AMERICA, INC. 

4. Are the DTC B1238 present and is parameter of "AMBIENT TEMP. SENSOR" fixed? 

YES  

Go to TERMINAL AND CONNECTOR INSPECTION procedure. 

NO  

Fault is intermittent caused by poor contact in the sensor's and/or A/C controller's connector or was 
repaired and A/C controller memory was not cleared. Thoroughly 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. 

TERMINAL AND CONNECTOR INSPECTION 

0 (32)

97.83

50 (122)

10.82

15 (59)

47.12

60 (140)

7.48

 

2008 Kia Sedona EX 

2008 HVAC Blower & A/C Controls (Automatic) - Sedona

  

Microsoft 

 

Monday, May 24, 2010 3:56:08 PM

Page 68 

© 2006 Mitchell Repair Information Company, LLC. 

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? 

YES  

Repair as necessary and go to "VERIFICATION OF VEHICLE REPAIR" procedure. 

NO  

Go to "SIGNAL CIRCUIT INSPECTION" procedure. 

SIGNAL CIRCUIT INSPECTION 

1. Check for open in harness. 

1. Ignition "OFF"  

2. Disconnect ambient temp, sensor.  

3. Measure resistance between terminal "1" of ambient temp, sensor and terminal "4" of A/C Control 

Unit. 

Specification: Approx. 0 ohms 

Fig. 76: Checking Resistance Between Terminal "1" Of Ambient Temp, Sensor And 
Terminal "4" Of A/C Control Unit 
Courtesy of KIA MOTORS AMERICA, INC. 

4. Is the measured resistance within specifications? 

 

2008 Kia Sedona EX 

2008 HVAC Blower & A/C Controls (Automatic) - Sedona

  

Microsoft 

 

Monday, May 24, 2010 3:56:08 PM

Page 69 

© 2006 Mitchell Repair Information Company, LLC.