B1020 — Evaporator Temperature Sensor Circuit Fault
Seen on: Heavy Truck
Evaporator Temperature Sensor Circuit Fault. Common causes: Evap temp sensor failure.
Your code rides along, so nearby mechanics see the fault before they quote you.
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.
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.