P0180 on the 5.9L Cummins 24V is a fuel temperature sensor A circuit malfunction. The 1998.5 to 2002 24V uses a fuel temperature sensor so the ECM can correct fueling and injection timing for how the fuel density changes with temperature. P0180 sets when the sensor signal is outside the plausible electrical range, indicating a wiring fault or a failed sensor.
Fuel temperature might seem minor, but the ECM uses it to compensate fueling as fuel warms or cools, which affects both power and economy. On the VP44-equipped 24V the sensor also plays into the pump's fuel correction, so a bad reading can subtly change how the truck drives. Because this is a simple thermistor circuit, P0180 is generally a straightforward wiring or sensor repair.
What P0180 means
The fuel temperature sensor is a thermistor whose resistance changes with fuel temperature. The ECM converts that resistance to a temperature value. P0180 sets when the signal is out of range, whether stuck high, stuck low, or missing, telling the ECM the circuit or sensor is not working correctly. It is an electrical range code rather than a rationality check.
Common causes
- Failed fuel temperature sensor
- Open or shorted signal or ground wire
- Corroded or loose sensor connector
- Chafed harness near the injection pump or fuel system
- Poor sensor ground
Symptoms
- Check engine light with P0180 stored
- Minor changes in power or fuel economy
- Slightly altered fueling correction
- Often little noticeable drivability change
- Companion fuel temperature or timing codes
How to diagnose it
View the fuel temperature reading with a scan tool. A value pinned at an extreme high or low, or reading implausibly compared to ambient after a cold soak, confirms the fault. Inspect the sensor connector for corrosion and a secure fit. Back-probe the circuit and check for the signal and ground; unplugging the sensor should drive the reading to an extreme if the wiring is intact. Check the signal wire for opens and shorts back to the ECM, and measure the sensor resistance against a temperature chart.
How to fix it
Repair open or shorted wiring and clean or replace a corroded connector, which resolves many P0180 cases. Confirm a clean sensor ground. If the wiring is good but the sensor reads out of range, replace the fuel temperature sensor. After the repair, clear the code, verify the fuel temperature reading is plausible for the conditions, and road test. For the correct fuel temperature sensor for your 24V Cummins, contact sales@coredieselparts.com.
Frequently asked questions
Is P0180 serious on a 24V Cummins?
It is usually mild for drivability, but incorrect fuel temperature data can slightly affect fueling and economy. Repair it to keep the ECM's fuel correction accurate.
Where is the fuel temperature sensor located?
It is in the fuel system near the injection pump circuit on the 24V. Its exact location varies, so consult a diagram for your year when tracing the connector and wiring.
Can a bad ground cause P0180?
Yes. A poor or open ground makes the signal read out of range and can set the code. Always confirm a clean sensor ground before replacing the sensor.
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