Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSFORD2012FOCUS L4-2.0LREPAIR AND DIAGNOSISHEATING AND AIR CONDITIONINGTESTING AND INSPECTIONPINPOINT TESTSCLIMATE CONTROL - DATCDIAGNOSTIC ROUTINE U
2012 Ford Focus L4-2.0L
Diagnostic Routine U
2012 Ford Focus L4-2.0LSECTION Diagnostic Routine U
Diagnostic Routine U
Diagnostic Overview
B10B3:00, B10B4:00, B10B5:00, B10B6:00
Refer to Wiring Diagram Set 55 for schematic and connector information Electrical Diagrams.
DTC Fault Trigger Conditions
Pinpoint Test
1. CHECK THE AIR DISCHARGE TEMPERATURE SENSOR OUTPUT VOLTAGE
1. Ignition ON.
2. Turn the HVAC (Heating, Ventilation, and Air Conditioning) system on.
3. Disconnect: the appropriate air discharge temperature sensor:
- left panel air discharge temperature sensor C2438
- left floor air discharge temperature sensor C2436
- right panel air discharge temperature sensor C2439
- right floor air discharge temperature sensor C2437
4. Measure:
Is the voltage between 4.7 and 5.1 volts?
2. CHECK THE AIR DISCHARGE TEMPERATURE SENSOR SIGNAL CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.
3. Measure:
Is the resistance less than 3 ohms?
3. CHECK THE AIR DISCHARGE TEMPERATURE SENSOR SIGNAL RETURN CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
4. CHECK THE AIR DISCHARGE TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND
1. Measure:
Is the resistance greater than 10,000 ohms?
5. CHECK THE AIR DISCHARGE TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition ON.
2. Measure:
Is any voltage present?
6. CHECK AIR DISCHARGE TEMPERATURE SENSOR SIGNAL CIRCUIT AND THE SIGNAL RETURN FOR A SHORT TO TOGETHER
1. Ignition OFF.
2. Measure:
Is the resistance greater than 10,000 ohms?
7. CHECK FOR CORRECT HVAC (Heating, Ventilation, and Air Conditioning) MODULE OPERATION
1. Ignition OFF.
2. Disconnect and inspect all the HVAC (Heating, Ventilation, and Air Conditioning) module connectors.
3. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary
4. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.