B1020 — Evaporator Temperature Sensor Circuit Fault
What it means: Evaporator Temperature Sensor Circuit Fault.
How serious / can you keep driving: Informational. Usually OK to continue — monitor closely.
Check first: Measure evap temp sensor resistance
Don't risk it — look up listed providers near you and give them this code when you call.
Listed providers nearest Albuquerque, NM
Closest first. Tell them B1020 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Albuquerque, NM · (505) 226-2125
- 0.0 mi away — based in Albuquerque, NM · (505) 823-9696
- 0.0 mi away — based in Albuquerque, NM · (505) 220-3541
Seen on: Heavy Truck
What B1020 means
Evaporator Temperature Sensor Circuit Fault. Common causes: Evap temp sensor failure.
How serious is it?
Informational. Usually OK to continue — monitor closely.
Most likely causes
- Evap temp sensor failure
- Failed thermistor
- wiring fault
First moves (roadside)
- Measure evap temp sensor resistance
- compare to temperature chart
FAQ
Evaporator Temperature Sensor Circuit Fault. Common causes: Evap temp sensor failure.
Informational — Usually OK to continue — monitor closely.
The most common cause is: Evap temp sensor failure. Other possibilities include Failed thermistor; wiring fault.
Usually OK to continue — monitor closely. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside B1020, or share the same subsystem.
- Blower Motor Circuit Open (B1004)
- Blower Motor Circuit Short to Ground (B1005)
- APU HVAC Communication Fault (B1050)
- Coolant/Diesel Heater Circuit Fault (B1052)
- HVAC Control Module Voltage High (B1001)
- HVAC Control Module Voltage Low (B1002)
- A/C Pressure Sensor Circuit Fault (B1010)
- Air Distribution Actuator Fault (B1040)
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.