P0184: The engine computer sees the fuel temperature sensor A signal jump or drop out in a way real fuel temperature cannot.
Fuel temperature sensor A signal drops in and out
Severity: Severity not verified — if the car runs badly, have it inspected
The sources describe the code and its causes but do not say how urgent it is. The usual symptoms are a check engine light and some loss of fuel economy, so have it read and checked rather than ignored.
P0184 in short
P0184 means the engine computer saw the fuel temperature sensor A signal change faster than fuel can really change temperature. TroubleCodes.net describes a swing of more than 10 degrees C within 100 milliseconds. Loose or corroded wiring and connectors are the usual causes, and the sensor itself is a less common one.
A real fuel temperature cannot jump by tens of degrees in a fraction of a second. When the signal does, the computer decides the circuit is intermittent and sets P0184.
Because the fault comes and goes, it can be hard to reproduce. Shaking the harness while watching the reading is the standard way to bring it out.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Intermittent wiring or connector fault
Common general cause- Why it ranks here
- A signal that drops in and out points at a loose pin, corroded connector or chafed wire before a failed sensor.
- What would change this
- Rises if the connector is corroded or the reading jumps when the harness is moved. Falls if wiring and connectors test normal.
Cause 2: Failed temperature sensor
Common general cause- Why it ranks here
- TroubleCodes.net lists the sensor itself as a possible cause, though less common than the wiring.
- What would change this
- Rises if the circuit tests good and the sensor resistance is outside the manual figures. Falls if the resistance is correct.
Cause 3: Engine computer fault (rare)
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists the computer as a rare cause, often after water or collision damage.
- What would change this
- Rises only after wiring and sensor test good. Falls if either is faulty.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all stored codes and freeze-frame data.
IfOther codes are stored with it
It meansSort out the other codes first, since a shared wiring or power fault can set several.
IfP0184 is the only code
It meansMove on to the connector and wiring checks.
Step 2: Inspect the sensor and ECM connectors for bent pins, corrosion and water, then wiggle the harness with the key on while watching the fuel temperature reading for jumps.
Warning:Keep hands and tools clear of belts and fans if the engine is running, and do not disconnect fuel lines.
IfA damaged, corroded or loose connection is found, or the reading jumps when the harness moves
It meansThe wiring or connector is the likely cause.
IfWiring and connectors look and test normal
It meansTest the sensor and its reference voltage next.
Step 3: Check 5 volts reference and signal voltage at the sensor while flexing the harness.
Warning:Back-probing can short pins and damage the computer. Use a wiring diagram and turn the ignition off when moving the probe.
IfVoltage, resistance or continuity is outside the repair manual figures
It meansThe wiring or the sensor is at fault, so repair the wiring or replace the sensor.
IfEverything tests normal
It meansThe fault may be intermittent or in the computer, so have a shop retest.
Symptoms
- Check engine light on
- Poorer fuel economy
- Hard starting or reduced performance, in some cases
How to fix
Step 1: With the ignition off, look at the visible wiring and connector for the sensor for damage or corrosion.
Step 2: Ask a dealer or shop to check the circuit before buying a sensor for P0184.
On your vehicle
We don't have reviewed vehicle-specific evidence for P0184 yet. The causes and tests above apply across vehicles.
Related codes
No curated relationships for P0184 yet.
P0184 questions
Is it safe to drive with P0184?
The sources list a check engine light and poorer fuel economy as the usual signs, but they do not rate urgency. Have it read and checked soon.
Sources and review
- P0184 - Fuel temperature sensor A circuit intermittent
- On-Board Diagnostic Trouble Codes (generic code title list)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error