The P0187: Fuel Temperature Sensor B Circuit Low Input refers to a problem within the fuel temperature sensor B circuit, specifically indicating that the circuit is reporting a lower-than-expected voltage. This issue can result from various causes, such as a faulty sensor, wiring problems, or a malfunctioning Powertrain Control Module (PCM). In simple terms, when this code appears, it suggests that the sensor isn’t receiving or sending the correct voltage, which could impact the vehicle’s fuel management and performance.
P0187 – Quick Overview
| Meaning | P0187: Fuel Temperature Sensor B Circuit Low Input |
| Is it serious? | Yes, this code can be serious as it indicates a problem with the fuel temperature sensor, which could lead to improper fuel management and poor engine performance. |
| Possible causes | – Low voltage in the fuel temperature sensor circuit – Faulty fuel temperature sensor – Wiring or connector issues – Faulty PCM |
| How to diagnose? | – Measure the voltage in the fuel temperature sensor circuit. – Inspect the sensor for proper operation. – Check wiring and connectors for defects. – Replace or repair any faulty components. |
P0187 Meaning
The P0187: Fuel Temperature Sensor B Circuit Low Input means that the sensor measuring the fuel temperature in your car is receiving or sending a voltage that is too low. This could be due to a faulty sensor, problems with the wiring, or an issue with the car’s computer (PCM). When this code shows up, it suggests that the fuel temperature is not being accurately monitored, which could affect your engine’s performance and fuel efficiency.
Step-by-step diagnostic guide
Follow the outline procedure to diagnose this DTC by eliminating possible causes one by one.
| Action | Description | Tools Needed |
|---|---|---|
| Check for Other Codes | Use an OBD-II scanner to check if there are any other related codes present. These might give additional clues about the problem. | OBD-II Scanner |
| Inspect the Fuel Temperature Sensor | Visually inspect the fuel temperature sensor for any signs of damage, corrosion, or disconnection. Ensure it is securely attached. | Flashlight, Safety Gloves |
| Measure the Voltage in the Fuel Temperature Sensor Circuit | Use a multimeter to measure the voltage in the sensor circuit. Compare the readings to the manufacturer’s specifications. | Multimeter, Manufacturer’s Specifications |
| Inspect Wiring and Connectors | Carefully check the wiring and connectors leading to the sensor for any signs of wear, corrosion, or breaks. Look for loose or disconnected wires. | Flashlight, Multimeter |
| Repair or Replace Damaged Wiring/Connectors | If any wiring or connectors are damaged or corroded, repair or replace them. Ensure connections are secure and free from dirt or corrosion. | Wire Strippers, Electrical Tape, Replacement Wires/Connectors |
| Check the PCM (Powertrain Control Module) | Inspect the PCM and its connections for any signs of damage or loose connections. If the PCM is suspected to be faulty, it may need reprogramming or replacement. | OBD-II Scanner, Multimeter |
| Clear the Code and Test Drive | After completing the necessary repairs, clear the P0187 code using the OBD-II scanner. Take the vehicle for a test drive to ensure the issue is resolved and the code does not return. | OBD-II Scanner, Vehicle Owner’s Manual |
| Recheck for Codes | After the test drive, re-scan the vehicle to ensure the P0187 code has not reappeared. If the code returns, further diagnosis may be required. | OBD-II Scanner |
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I test OBD-II scanners and make DIY Engine diagnostics guides to help you solve your car problems without having to depend on the mechanic. A lot of them will try to scam you or are just no help at all. About Juraj Lukacko