Home › Fault codes › B1002
B1002 — HVAC Control Module Voltage Low
CautionHVACLimp to the next safe stop
Seen on: Heavy Truck
HVAC Control Module Voltage Low. Common causes: HVAC control module under-voltage.
Don't risk it — get a diesel tech on the truck.
Look up listed providers near you and give them this code when you call.
How serious is it?
Caution. Limp to the next safe stop.
Most likely causes
- HVAC control module under-voltage
- Battery or alternator fault
- high resistance connection
First moves (roadside)
- Check battery voltage
- test alternator output
- inspect power connections
FAQ
What does B1002 mean?
HVAC Control Module Voltage Low. Common causes: HVAC control module under-voltage.
How serious is B1002?
Caution — Limp to the next safe stop.
What's the most likely cause of B1002?
The most common cause is: HVAC control module under-voltage. Other possibilities include Battery or alternator fault; high resistance connection.
Can I keep driving with B1002?
Limp to the next safe stop. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Throwing this code right now?
Find a mechanic or related guides
General diagnostic guidance for diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack and more). Not a substitute for a scan-tool diagnosis on your specific truck.