P0187 moderate

Fuel Temperature Sensor B Circuit High

The P0187 code means the vehicle's onboard diagnostic system has detected: Fuel Temperature Sensor B Circuit High. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
moderate
Estimated cost
$60 - $300 (parts and labor)
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Common Symptoms

  • Check Engine Light illuminated
  • Fuel temperature reads extremely low or -40F on scan tool
  • Engine may run rough in cold conditions
  • Fuel delivery calculations may be inaccurate

Probable Causes (Ranked by Likelihood)

  • Open circuit in fuel temp sensor B wiring Very High
  • Failed fuel temperature sensor B (open) High
  • Disconnected or corroded connector Moderate
  • PCM pull-up resistor fault Low

Step-by-Step Diagnostic Procedure

  1. Read fuel temp sensor B on scan tool. A reading of -40F (-40C) confirms an open circuit condition.

  2. Inspect the sensor connector for being unplugged, corroded, or having backed-out pins.

  3. Measure sensor resistance. Infinite ohms confirms open sensor.

  4. Test wiring continuity from sensor connector to PCM.

Frequently Asked Questions

What does circuit high mean for a fuel temp sensor?

For an NTC sensor, circuit high means high resistance or open circuit. The PCM reads this as extremely low temperature.

Can a disconnected connector cause P0187?

Yes, if the connector was not properly reconnected after fuel system service, P0187 will set immediately.

Will P0187 affect cold starting?

It can. The PCM uses fuel temperature to calculate injection quantity. Without an accurate reading, cold start fuel delivery may be incorrect.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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