PINPOINT TEST F: DTCs B1B71:11 AND 15

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F1 CHECK THE EVAPORATOR TEMPERATURE SENSOR RESISTANCE

Ignition OFF.
Disconnect: Evaporator Temperature Sensor C296.

Measure the resistance between the evaporator temperature sensor C296 terminals, component side and compare to the table below.

Ambient Temperature	Resistance
-20°C (-4°F)	26, 090-27, 347 ohms
-15°C (5°F)	19, 721-20, 485 ohms
-10°C (14°F)	15, 007-15, 497 ohms
-5°C (23°F)	11, 510-11, 818 ohms
0°C (32°F)	8, 910-9, 090 ohms
5°C (41°F)	6, 906-7, 090 ohms
10°C (50°F)	5, 400-5, 571 ohms
15°C (59°F)	4, 251-4, 408 ohms
20°C (68°F)	3, 372-3, 513 ohms
25°C (77°F)	2, 694-2, 819 ohms
30°C (86°F)	2, 166-2, 276 ohms
35°C (95°F)	1, 752-1, 849 ohms
40°C (104°F)	1, 426-1, 511 ohms
45°C (113°F)	1, 167-1, 242 ohms
50°C (122°F)	960-1, 026 ohms
55°C (131°F)	794-852 ohms
60°C (140°F)	661-711 ohms

Fig 1: Measuring Resistance Between Evaporator Temperature Sensor C296 Terminals, Component Side

Courtesy of FORD MOTOR CO.

Is the resistance within the specified values for the temperatures?

Yes : GO to F2.
No : INSTALL a new evaporator temperature sensor. REFER to CLIMATE CONTROL . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

F2 CHECK THE HVAC MODULE OUTPUT VOLTAGE
- Ignition ON.
- Press the POWER button.
- Measure the voltage between evaporator temperature sensor C296-2, circuit VH406 (VT/BN), harness side and C296-1, circuit RH111 (GY/BU), harness side.
  
  Fig 2: Measuring Voltage Between Evaporator Temperature Sensor C296-2, Circuit VH406 (VT/BN) And C296-1, Circuit RH111 (GY/BU)
  Courtesy of FORD MOTOR CO.
- Is the voltage between 4.7 and 5.1 volts?
- Yes : INSTALL a new evaporator temperature sensor. REFER to CLIMATE CONTROL . CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation. If the DTC returns, GO to F8.
- No : For DTC B1B71:15 , GO to F3.
  For DTC B1B71:11 , GO to F6.
F3 CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: HVAC Module C228.
- Ignition ON.
- Measure the voltage between ground and HVAC module C228-19, circuit VH406 (VT/BN), harness side.
  
  Fig 3: Measuring Voltage Between Ground And HVAC Module C228-19, Circuit VH406 (VT/BN), Harness Side
  Courtesy of FORD MOTOR CO.
- Is any voltage present?
- Yes : REPAIR circuit VH406 (VT/BN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
- No : GO to F4.
F4 CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between HVAC module C228-19, circuit VH406 (VT/BN), harness side and evaporator temperature sensor C296-2, circuit VH406 (VT/BN), harness side.
  
  Fig 4: Measuring Resistance Between HVAC Module C228-19, Circuit VH406 (VT/BN) And Evaporator Temperature Sensor C296-2, Circuit VH406 (VT/BN)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to F5.
- No : REPAIR circuit VH406 (VT/BN) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
F5 CHECK THE SIGNAL RETURN CIRCUIT FOR AN OPEN
- Measure the resistance between HVAC module C228-23, circuit RH111 (GY/BU), harness side and evaporator temperature sensor C296-1, circuit RH111 (GY/BU), harness side.
  
  Fig 5: Measuring Resistance Between HVAC Module C228-23, Circuit RH111 (GY/BU) And Evaporator Temperature Sensor C296-1, Circuit RH111 (GY/BU)
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
- Yes : GO to F8.
- No : REPAIR circuit RH111 (GY/BU) for an open. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
F6 CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO THE SIGNAL RETURN CIRCUIT
- Ignition OFF.
- Disconnect: HVAC Module C228.
- Measure the resistance between evaporator temperature sensor C296-2, circuit VH406 (VT/BN), harness side and C296-1, circuit RH111 (GY/BU), harness side.
  
  Fig 6: Measuring Resistance Between Evaporator Temperature Sensor C296-2, Circuit VH406 (VT/BN) And C296-1, Circuit RH111 (GY/BU)
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10, 000 ohms?
- Yes : GO to F7.
- No : REPAIR circuit VH406 (VT/BN) for a short to circuit RH111 (GY/BU). CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
F7 CHECK THE EVAPORATOR TEMPERATURE SENSOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and HVAC module C228-19, circuit VH406 (VT/BN), harness side.
  
  Fig 7: Measuring Resistance Between Ground And HVAC Module C228-19, Circuit VH406 (VT/BN), Harness Side
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10, 000 ohms?
- Yes : GO to F8.
- No : REPAIR circuit VH406 (VT/BN) for a short to ground. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
F8 CHECK THE HVAC MODULE CONNECTION
- Inspect the HVAC module connectors for:
  - corrosion.
  - pushed-out terminals.
  - damaged terminals.
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- Yes : INSTALL a new HVAC module. REFER to CLIMATE CONTROL . TEST the system for normal operation.
- No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.