Pinpoint Test M : B1B71:11, B1B71:15

WARNING: This page is about a different car, the 2018 Ford EcoSport. However, it is still accessible from the selected car via links, so may be relevant.

Automatic Climate Control System for schematic and connector information.

Normal Operation and Fault Conditions

The evaporator temperature sensor, REFER to: Climate Control System - Vehicles With: Electronic Automatic Temperature Control (EATC) - System Operation and Component Description .

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
HVAC B1B71:11	Evaporator Temperature Sensor: Circuit Short To Ground	The HVAC control module senses lower than expected voltage on the sensor feedback circuit, indicating a short to ground.
HVAC B1B71:15	Evaporator Temperature Sensor: Circuit Short To Battery Or Open	The HVAC control module senses greater than expected voltage on the sensor feedback circuit, indicating a short to voltage, an open circuit or sensor.

Possible Sources

Wiring, terminals or connectors
Evaporator temperature sensor
HVAC control module

NOTE: Use the correct probe adapter(s) when making measurements. Failure to. Use the correct probe adapter(s) may damage the connector.

M1 CHECK THE EVAPORATOR TEMPERATURE SENSOR CIRCUITS FOR A SHORT TO VOLTAGE

Ignition OFF.

Disconnect HVAC control module C294A.

Disconnect Evaporator temperature sensor C296.

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Refer to C296-1	Courtesy of FORD MOTOR COMPANY	Ground
Refer to C296-2	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the circuit.

GO to M2

M2 CHECK THE EVAPORATOR TEMPERATURE SENSOR CIRCUITS FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Refer to C296-1	Courtesy of FORD MOTOR COMPANY	Ground
Refer to C296-2	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance greater than 10, 000 ohms?

Yes

GO to M3

No	REPAIR the circuit.

M3 CHECK THE EVAPORATOR TEMPERATURE SENSOR CIRCUITS FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
Refer to C296-1	Courtesy of FORD MOTOR COMPANY	Refer to C294A-19
Refer to C296-2	Courtesy of FORD MOTOR COMPANY	Refer to C294A-2

Is the resistance less than 3 ohms?

Yes

GO to M4

No	REPAIR the circuit.

M4 CHECK THE EVAPORATOR TEMPERATURE SENSOR CIRCUITS FOR A SHORT TOGETHER

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Refer to C296-1	Courtesy of FORD MOTOR COMPANY	Refer to C296-2

Is the resistance less than 10, 000 ohms?

Yes	INSTALL a new evaporator temperature sensor. REFER to: Evaporator Temperature Sensor . TEST the system for normal operation. If the concern is still present, GO to M5

No	REPAIR the circuits.

M5 CHECK FOR CORRECT HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE OPERATION

Ignition OFF.

Disconnect and inspect all HVAC control module electrical connectors (if not previously disconnected).

Repair:
- corrosion (install new connector or terminal - clean module pins)
- damaged or bent pins - install new terminals or pins
- pushed-out pins - install new pins as necessary

Connect all HVAC control module electrical connectors. Make sure they seat and latch correctly.

Operate the system and determine if the concern is still present.

Is the concern still present?

Yes

CHECK OASIS for any applicable Technical Service Bulletins (TSBs). If a TSB exists for this concern, DISCONTINUE this test and FOLLOW the TSB instructions. If no Technical Service Bulletins (TSBs) address this concern, INSTALL a new HVAC control module. REFER to: Heating, Ventilation and Air Conditioning (HVAC) Control Module .

No	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. ADDRESS the root cause of any connector or pin issues.