Pinpoint Test X: B12CA:11, B12CA:15

WARNING: This page is about a different car, the 2023 Ford Bronco. However, it is still accessible from the selected car via links, so may be relevant.

Refer to applicable wiring diagrams for schematic and connector information.

Normal Operation and Fault Conditions

The auto start-stop deactivation switch, REFER to: Climate Control System - Vehicles With: Electronic Manual Temperature Control (EMTC) - System Operation and Component Description .

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
HVAC B12CA:11	Start/Stop 'Eco-Start' Status Indicator: Circuit Short To Ground	This DTC sets when the HVAC control module senses lower than expected voltage on the circuits, indicating a short to ground.
HVAC B12CA:15	Start/Stop 'Eco-Start' Status Indicator: Circuit Short To Battery Or Open	This DTC sets when the HVAC control module senses greater than expected voltage on the circuits, indicating a short to voltage.

Possible Sources

Wiring, terminals or connectors
Auto Start-Stop Deactivation Switch
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.

X1 CHECK THE AUTO START-STOP DEACTIVATION SWITCH CIRCUITS FOR A SHORT TO VOLTAGE

Ignition OFF.

Disconnect HVAC control module C228A and C228B.

Disconnect Audio control panel

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C228A Pin 5	Courtesy of FORD MOTOR COMPANY	Ground
C228A Pin 13	Courtesy of FORD MOTOR COMPANY	Ground

Is any voltage present?

Yes	REPAIR the affected circuits.

GO to X2

X2 CHECK THE AUTO START-STOP DEACTIVATION SWITCH CIRCUITS FOR A SHORT TO GROUND

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C228A Pin 5	Courtesy of FORD MOTOR COMPANY	Ground
C228A Pin 13	Courtesy of FORD MOTOR COMPANY	Ground

Are the resistances greater than 10, 000 ohms?

Yes

GO to X3

No	REPAIR the affected circuits.

X3 CHECK THE AUTO START-STOP DEACTIVATION SWITCH CIRCUITS FOR AN OPEN

Measure:

Positive Lead	Measurement / Action	Negative Lead
C228A Pin 5	Courtesy of FORD MOTOR COMPANY	C20210 Pin 7
C228A Pin 13	Courtesy of FORD MOTOR COMPANY	C20210 Pin 4

Are the resistances less than 3 ohms?

Yes

GO to X4

No	REPAIR the affected circuits.

X4 CHECK THE AUTO START-STOP DEACTIVATION SWITCH CIRCUITS FOR A SHORT TOGETHER

Measure:

Positive Lead	Measurement / Action	Negative Lead
C20210 Pin 7	Courtesy of FORD MOTOR COMPANY	C20210 Pin 4

Is the resistance greater than 10, 000 ohms?

Yes	INSTALL a new Auto Start-Stop Deactivation Switch. CLEAR codes and CARRY out the HVAC control module self-test. TEST the system for normal operation. If the concern is still present, GO to X5

No	REPAIR the circuits.

X5 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. WAIT 20 seconds for the range calibration to be executed after reconnecting of the module before any further assessment or measurement is made. If the actuator range calibration does not start, or has been interrupted, PERFORM the HVAC Calibration Routine, using a diagnostic scan tool.

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

Is the concern still present?

Yes

CHECK OASIS for any applicable service articles: TSB, GSB, SSM or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles 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.