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B1001 — HVAC Control Module Voltage High
CautionHVACLimp to the next safe stop
Seen on: Heavy Truck
HVAC Control Module Voltage High. Common causes: HVAC control module over-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 over-voltage
- Charging system overvoltage
- alternator fault
First moves (roadside)
- Check charging system voltage
- should be 13.8-14.5V
- check for spikes
FAQ
What does B1001 mean?
HVAC Control Module Voltage High. Common causes: HVAC control module over-voltage.
How serious is B1001?
Caution — Limp to the next safe stop.
What's the most likely cause of B1001?
The most common cause is: HVAC control module over-voltage. Other possibilities include Charging system overvoltage; alternator fault.
Can I keep driving with B1001?
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.