Pinpoint Test Q: U3003:16, U3003:17

Refer to MANUAL CLIMATE CONTROL SYSTEM for schematic and connector information.

Normal Operation and Fault Conditions

The HVAC control module is supplied constant voltage and ground. Excessive resistance or an open in one or more of these circuits, a discharged battery or an inoperative charging system results in the HVAC control module setting a DTC.

DTC Fault Trigger Conditions

DTC	Description	Fault Trigger Condition
HVAC U3003:16	Battery Voltage: Circuit Voltage Below Threshold	This DTC sets when the HVAC control module senses lower than expected system voltage.
HVAC U3003:17	Battery Voltage: Circuit Voltage Above Threshold	This DTC sets when the HVAC control module senses greater than expected system voltage. This DTC may also set in the HVAC control module due to battery charging or vehicle jump starting events.

Possible Sources

Fuses
Wiring, terminals or connectors
Charging system concern
Battery
HVAC control module

Visual Inspection and Pre-checks

Make sure the vehicle battery terminals and cables are free of any corrosion and other contaminants.
Make sure the vehicle battery terminals are tightened to their correct torque specifications.
Make sure BCM fuse 21 (7.5A) is OK.
Inspect for loose or corroded HVAC control module connections.

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

Q1 CARRY OUT THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE SELF-TEST

Start the engine.

Using a diagnostic scan tool, carry out the HVAC control module self-test.

Using a diagnostic scan tool, clear the HVAC control module Diagnostic Trouble Codes (DTCs).

Ignition OFF.

Wait 10 seconds.

Start the engine.

Using a diagnostic scan tool, carry out the HVAC control module self-test.

Is DTC U3003:16 or U3003:17 still present?

Yes

GO to Q2

No	The system is operating normally at this time. The DTC may have been set previously during battery charging or while jump starting the vehicle.

Q2 CHECK FOR CHARGING SYSTEM DIAGNOSTIC TROUBLE CODES (DTCS) IN THE PCM (POWERTRAIN CONTROL MODULE)
- Ignition OFF.
- Ignition ON.
- Using a diagnostic scan tool, carry out the PCMKOEO self-test.
Are any charging system Diagnostic Trouble Codes (DTCs) present in the PCM?

Yes DIAGNOSE the charging system. REFER to: Charging System .

No GO to Q3

Q3 CHECK THE BATTERY CONDITION AND STATE OF CHARGE
- Carry out the Battery Condition Test diagnostic routine. REFER to: Battery .
Did the battery pass the condition test?

Yes GO to Q4

No INSTALL a new battery. REFER to: Battery .

Q4 CHECK THE CHARGING SYSTEM VOLTAGE

NOTE: Do not allow the engine Revolutions Per Minute (RPM) to exceed 2, 000 Revolutions Per Minute (RPM) while carrying out this step or the generator may self-excite, resulting in default charging system output voltage. If engine Revolutions Per Minute (RPM) exceeds 2, 000 Revolutions Per Minute (RPM), shut the vehicle off and restart the engine before carrying out this step.

Start the engine.

Measure:

Positive Lead	Measurement / Action	Negative Lead
Courtesy of FORD MOTOR COMPANY

For DTC
U3003:16 , turn the headlights on, set the HVAC fan on high and run engine at 1, 500 Revolutions Per Minute (RPM) for a minimum of 2 minutes.

For DTC
U3003:17 , turn off all accessories and run the engine at 1, 500 Revolutions Per Minute (RPM) for a minimum of 2 minutes.

Is the battery voltage between 13-15.2 volts?

Yes	For DTC U3003:16 , GO to Q5 For DTC U3003:17 , GO to Q7

No	DIAGNOSE the charging system. REFER to: Charging System .

Q5 CHECK THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE VOLTAGE SUPPLY CIRCUIT FOR HIGH RESISTANCE

Ignition OFF.

Disconnect HVAC control module C228A and C228B

Ignition ON.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C228A-26	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage greater than 11 volts?

Yes

GO to Q6

No	VERIFY the BCM fuse 21 (7.5A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the OEM ELECTRICAL WIRING DIAGRAM INTRODUCTION to identify the possible causes of the circuit short.

Q6 CHECK THE HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONTROL MODULE GROUND CIRCUIT FOR HIGH RESISTANCE

Ignition OFF.

Measure:

Positive Lead	Measurement / Action	Negative Lead
C228A-1	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes

GO to Q7

No	REPAIR the circuit.

Q7 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 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 module connections. ADDRESS the root cause of any connector or pin issues.