Pinpoint Test BJ: U0164
WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
- Normal Operation and Fault Conditions
REFER to: Electric Powertrain Control - Component Location .
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition SOBDMC U0164:00 Lost Communication With HVAC Control Module: No Sub Type Information This DTC sets when messages are missing from the HVAC module. Possible Sources
- Communications network concern
- HVAC module.
- BJ1 CARRY OUT A VEHICLE INSPECTION AND VERIFY THE SELF-TEST PROCEDURENOTE: If the self-test or communication concern occurred after a failed or aborted reprogram, the module may be blank. Attempt to reprogram the module again before continuing with this pinpoint test.
- Visually inspect the following for obvious signs of electrical damage:
- harness wiring
- electrical connections
- Verify the correct procedure was used to activate the self-test for the scan tool. REFER to: Electronic Engine Controls - System Operation and Component Description . Recreating the Fault.
Was the correct self-test procedure used?
Yes GO to BJ2 No REFER to: Electronic Engine Controls - System Operation and Component Description . Recreating the Fault. - Visually inspect the following for obvious signs of electrical damage:
- BJ2 CARRY OUT THE NETWORK TEST
- Note:
When using FDRS, the scan tool attempts to communicate with the PCM first. After establishing communication with the PCM, the scan tool then attempts to communicate with all modules on the vehicle. If an FDRS session cannot be established, FDRS may state no communication can be established with the PCM:
- Choose No when the scan tool prompts whether or not to retry communication.
- Enter a PCM part number, tear tag or calibration number to identify the vehicle and start a session. The PCM part number and 4- character tear tag are located on the PCM.
- Ignition ON.
Do all modules indicate pass?
Yes GO to BJ3 No GO to BJ4 - Note:
When using FDRS, the scan tool attempts to communicate with the PCM first. After establishing communication with the PCM, the scan tool then attempts to communicate with all modules on the vehicle. If an FDRS session cannot be established, FDRS may state no communication can be established with the PCM:
- BJ3 CHECK FOR A HVAC (HEATING, VENTILATION AND AIR CONDITIONING) CONCERN
- Using a diagnostic scan tool, perform the HVAC self-test.
- Check for any other HVAC related symptoms.
Is a concern present?
Yes REFER to: Climate Control System - Vehicles With: Dual Automatic Temperature Control (DATC) . 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. - BJ4 INVERTER SYSTEM CONTROLLER (ISC) SELF-TEST
- Confirm the Inverter System Controller (ISC) was the only module to fail.
Was the Inverter System Controller (ISC) the only module to fail?
Yes GO to BJ5 No DIAGNOSE the network concern. - BJ5 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) B+ CIRCUIT FOR VOLTAGE
- Ignition OFF.
- Disconnect Inverter System Controller (ISC) C1458A.
- Ignition ON.
Is the voltage greater than 10.5 volts?
Yes GO to BJ6 No REPAIR the circuit. - BJ6 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) VPWR CIRCUITS FOR VOLTAGE
- Ignition OFF.
- Connect a 5A fused jumper between:
Positive Lead Measurement / Action Negative Lead C1458A-K3 Ground
- Ignition ON.
- Measure and record:
Positive Lead Measurement / Action Negative Lead C1458A-L2 Ground C1458A-M2 Ground
Are the voltages greater than 10.5 volts?
Yes GO to BJ7 No REPAIR the circuit. - BJ7 CHECK THE INVERTER SYSTEM CONTROLLER (ISC) GROUND CIRCUITS FOR AN OPEN
- Ignition OFF.
- Measure and record:
Positive Lead Measurement / Action Negative Lead C1458A-L4 Ground C1458A-M4 Ground
Are the resistances less than 5 ohms?
Yes DIAGNOSE the network concern. No REPAIR the open circuit.