P4099 low

Diesel Throttle Valve Position Sensor Circuit Intermittent (Generic)

The P4099 code means the vehicle's onboard diagnostic system has detected: Diesel Throttle Valve Position Sensor Circuit Intermittent (Generic). This is a low severity code.

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Keep driving?
Yes, but fix soon
DIY difficulty
moderate
Estimated cost
$80 - $350 (parts and labor)
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Common Symptoms

  • Check Engine Light intermittent
  • Sporadic EGR control issues
  • Occasional rough shutdown
  • No significant power impact

Probable Causes (Ranked by Likelihood)

  • Loose throttle valve sensor connector Very High
  • Wiring chafing near intake High
  • Carbon buildup affecting valve movement Moderate
  • Intermittent ground connection Low

Step-by-Step Diagnostic Procedure

  1. Wiggle test sensor connector while monitoring data

  2. Inspect wiring near throttle valve

  3. Clean throttle valve and recheck

  4. Monitor sensor across multiple drive cycles

Frequently Asked Questions

Is P4099 urgent?

No, it is low severity. The throttle valve works most of the time. Schedule a repair at your convenience.

Can I drive with P4099?

Yes, you can drive normally. The intermittent nature means the system works most of the time.

Can carbon cause the intermittent issue?

Yes, carbon buildup on the throttle valve shaft can cause it to stick occasionally, affecting the position sensor reading.

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