Fault codeP0185

MODERATE

Fuel Temperature Sensor B Circuit Malfunction

What this code means

Fuel Temperature Sensor B Circuit Malfunction.

P0185 is a generic code: it means the same thing on every make. P0185 belongs to family P01xx — Fuel and air metering. Its page explains how to read a code and groups all its codes by part.

Type of fault

The control unit has detected an electrical anomaly on this circuit without saying exactly which. Diagnosis starts with a visual check of the wiring and connector, then measuring the component — resistance, supply, ground — with a multimeter.

Fuel temperature sensor

This sensor measures the temperature of the fuel, in the rail, the pump or the return line. Hot fuel is less dense: the control unit uses the temperature to correct the quantity injected, particularly on diesel engines.

What you notice

Often nothing; sometimes harder hot starts or a slight loss of power.

How to check it

Check the sensor's connector, often close to the high-pressure pump or the fuel filter, where diesel leaks can damage it. Engine cold, the fuel temperature should be close to the outside temperature, like the other temperature sensors.

Watch it live in Klaro

With an OBD2 adapter plugged in, these live readings show the part at work, when your car reports them:

Intake air temperature
Coolant temperature

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Clearing a code switches the light off but repairs nothing: if the fault remains, the code comes back. Clearing a fault code yourself →

How to read this code

PPowertrain
0standardised code
1Fuel and air metering
85P0185