P0407 EGR valve position sensor B signal reads too low

EGR sensor B circuit low

Severity not verified — if the car runs badly, have it inspected

TroubleCodes.net says drivers usually notice little beyond the warning lamp, possibly a reduced-performance mode, but no source rates the code, so the severity is not verified.

Source: how we rate severity

P0407 in short

P0407 means the engine computer sees the signal from EGR position sensor B as too low. Wiring and connector faults are the most common cause, then the sensor itself or a sticking EGR valve. The car usually drives normally with only the check engine light on, but have it tested to protect emissions and fuel economy.

The computer watches the position sensor on the exhaust gas recirculation valve to know how far the valve is open. The PCM sees abnormally low voltage in the sensor B circuit. The delaware and troublecodes lists both define it as the EGR position sensor B circuit, low.

The letter B marks a second sensor or circuit, and which part that is depends on the engine, so the maker's information is needed to find it.

Wiring and the sensor itself are the first things to test. Carbon in the valve can add to the problem.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

  1. Damaged, corroded or loose wiring or connector at the EGR position sensor

    Common general cause
    Why it ranks here
    TroubleCodes.net lists wiring and connector faults first, and a circuit voltage code is a circuit fault by definition.
    What would change this
    Rises if the harness shows chafing, corrosion or a loose pin. Falls if wiring and connector test clean.

  2. Failed EGR valve position sensor

    Common general cause
    Why it ranks here
    The code names the sensor B signal, and TroubleCodes.net lists a defective position sensor, including heat failure.
    What would change this
    Rises if wiring is good and the sensor signal stays out of range. Falls if the signal moves normally.

  3. Carbon buildup or a faulty actuator limiting EGR valve movement

    Possible — needs testing
    Why it ranks here
    TroubleCodes.net lists carbon and faulty solenoids or stepper motors as possible causes, but a sticking valve usually sets flow or performance codes rather than a voltage code.
    What would change this
    Rises if the valve is stuck or sooty. Falls if it moves freely.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. Read all stored codes and freeze-frame data, and use the maker's information to find which sensor is circuit B on your engine.

    Low riskTool: OBD-II scan tool

  2. With the engine off and cool, look over the EGR sensor connector and visible harness for damage, bent pins, corrosion or water.

    Low risk

  3. Have the sensor reference voltage, ground and signal measured with the key on, and the valve checked for free movement and carbon.

    Best left to a shopTool: digital multimeter, scan tool

    Warning:The EGR valve and its pipes get very hot after running, and probing connectors can short a circuit and damage the computer. Let the engine cool and leave this to a shop.

Symptoms

  • Check engine light on
  • Little or no change in how the car drives
  • Possible reduced performance and slightly worse fuel economy

How to fix

On your vehicle

Jeep

  • 2020–2021 · Wrangler

    Supported by vehicle data

    NHTSA flat-file summary of Jeep bulletin S2025000005 Rev.-jeep (summary: a lit MIL with P0407 (EGR sensor B circuit low) or P0408 (EGR sensor B circuit high) set); and 9004343-jeep (summary: when replacing the high pressure EGR valve because of P0407 or P0408, follow all published diagnosis first; these codes are for the low pressure EGR system). Whether it is still current is not verified.

  • S2025000005 Rev.-jeepStatus unverified

    MIL with P0407 or P0408

    2020wrangler · issued · NHTSA 10215894

    NHTSA flat-file summary only; the full bulletin was not read. The summary mentions a lit MIL with P0407 (EGR sensor B circuit low) or P0408 (EGR sensor B circuit high) set.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 9004343-jeepStatus unverified

    High pressure EGR valve and P0407/P0408

    2020–2021wrangler · issued · NHTSA 10215835

    NHTSA flat-file summary only; the full bulletin was not read. The summary mentions when replacing the high pressure EGR valve because of P0407 or P0408, follow all published diagnosis first; these codes are for the low pressure EGR system.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Ram

  • 2020–2021 · 1500

    Supported by vehicle data

    NHTSA flat-file summary of Ram bulletin S2025000005 Rev.-ram (summary: a lit MIL with P0407 (EGR sensor B circuit low) or P0408 (EGR sensor B circuit high) set); and 9004343-ram (summary: when replacing the high pressure EGR valve because of P0407 or P0408, follow all published diagnosis first; these codes are for the low pressure EGR system). Whether it is still current is not verified.

  • S2025000005 Rev.-ramStatus unverified

    MIL with P0407 or P0408

    20201500 · issued · NHTSA 10215894

    NHTSA flat-file summary only; the full bulletin was not read. The summary mentions a lit MIL with P0407 (EGR sensor B circuit low) or P0408 (EGR sensor B circuit high) set.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 9004343-ramStatus unverified

    High pressure EGR valve and P0407/P0408

    2020–20211500 · issued · NHTSA 10215835

    NHTSA flat-file summary only; the full bulletin was not read. The summary mentions when replacing the high pressure EGR valve because of P0407 or P0408, follow all published diagnosis first; these codes are for the low pressure EGR system.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Dodge

  • 2010–2012 · Ram 1500

    Supported by vehicle data

    NHTSA flat-file summary of Dodge bulletin S2025000005-dodge (summary: a lit MIL with P0407 (EGR sensor B circuit low) or P0408 (EGR sensor B circuit high) set). Whether it is still current is not verified.

  • S2025000005-dodgeStatus unverified

    MIL with P0407 or P0408

    2010–2012ram-1500 · issued · NHTSA 10223525

    NHTSA flat-file summary only; the full bulletin was not read. The summary mentions a lit MIL with P0407 (EGR sensor B circuit low) or P0408 (EGR sensor B circuit high) set.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

No curated relationships for P0407 yet.

All Turbocharging, fuel pressure and EGR codes

P0407 questions

Can I drive with P0407?

TroubleCodes.net says most drivers notice little beyond the warning lamp, but the engine may limit performance. Have it checked rather than ignoring it.

Sources and review

  1. P0407 trouble code page — TroubleCodes.net
  2. S2025000005 Rev.: MIL with P0407 or P0408 — Jeep
  3. 9004343: High pressure EGR valve and P0407/P0408 — Jeep
  4. S2025000005 Rev.: MIL with P0407 or P0408 — Ram
  5. 9004343: High pressure EGR valve and P0407/P0408 — Ram
  6. S2025000005: MIL with P0407 or P0408 — Dodge
  7. On-Board Diagnostic Trouble Codes (generic code title list) — Delaware Division of Motor Vehicles
Last reviewed
Written by
Saurabh K.
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