What Does P0187 Mean?
The fuel temperature sensor B circuit is reading lower voltage than expected, which the ECM interprets as an abnormally low fuel temperature. This typically indicates a sensor circuit issue rather than actually cold fuel. The driver may not notice any symptoms, though fuel delivery calculations may be slightly affected.
Common Causes
35%
Fuel temperature sensor B has failed with low internal resistance (shorted thermistor)
25%
Short to ground in the sensor signal wire
20%
Corroded or water-damaged connector causing low-resistance path to ground
12%
Damaged sensor wiring pinched against metal component
8%
ECM internal pull-down or input circuit fault
Diagnostic Steps
1
Check the fuel temperature sensor B PID — if it reads an implausibly low temperature (e.g., -40°F) the circuit is likely shorted to ground.
2
Unplug the sensor connector and check if the PID jumps to maximum reading. If it does, the wiring is good and the sensor is shorted internally — replace the sensor.
3
With the sensor unplugged, measure resistance between the signal wire and ground at the ECM connector. Any reading below 10 kΩ indicates a short to ground in the harness.
4
Inspect the wiring harness for chafing, especially where it routes near the fuel rail, exhaust components, or sharp bracket edges.
5
Measure sensor resistance directly — compare to spec (should be ~2.4 kΩ at 68°F). A reading below 100 Ω at room temperature confirms a failed sensor.
Estimated Repair Cost
$40 - $200
Parts + labor, varies by vehicle and location
The fuel temperature sensor B circuit is reading lower voltage than expected, which the ECM interprets as an abnormally low fuel temperature. This typically indicates a sensor circuit issue rather than actually cold fuel. The driver may not notice any symptoms, though fuel delivery calculations may ...
The most common cause of P0187 (Fuel Temperature Sensor B Circuit Range/Performance) is: Fuel temperature sensor B has failed with low internal resistance (shorted thermistor)
Typical repair costs for P0187 range from $40 to $200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive. The ECM defaults to a substitute fuel temperature value. You may experience minor fuel economy changes. No immediate safety risk exists. Schedule repair when convenient.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0187 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
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