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DTC codes / P2Dxx · Hybrid propulsion / P2D14

P2D14Exhaust Flow Control Valve C Control Circuit Low

P2D14 indicates that the powertrain control module has detected a low-voltage condition on the control circuit for the exhaust flow control valve, which is used to manage exhaust backpressure and flow. The computer expects a certain voltage on the control wire when commanding the valve, but the signal is lower than expected, indicating a short to ground, an open circuit, or a faulty valve.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • Reduced engine performance or power, especially under load or during regeneration.
  • Rough idle or hesitation when the valve is commanded to change position.
  • Increased exhaust noise or a change in exhaust tone.
  • Poor fuel economy or increased emissions.
  • In some cases, the vehicle may enter limp mode to protect the exhaust system.

Common causes, most likely first

  1. Damaged or chafed wiring in the control circuit, causing a short to ground.
  2. Corroded or loose electrical connectors at the valve or PCM.
  3. Failed exhaust flow control valve solenoid or actuator.
  4. Open circuit in the control wire due to a broken wire or poor terminal tension.
  5. Faulty powertrain control module (PCM) driver circuit, though rare.
  6. Aftermarket accessories or modifications interfering with the circuit.

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related codes in other modules.
  2. Inspect the wiring harness and connectors for damage, corrosion, or loose pins, especially near the exhaust valve and PCM.
  3. Measure resistance of the control circuit to check for an open or short to ground, comparing to manufacturer specifications.
  4. Test the exhaust flow control valve with a bidirectional scan tool to command it open and closed while monitoring voltage and listening for operation.
  5. Check for technical service bulletins (TSBs) or known issues for the specific vehicle make and model.
  6. If the valve fails to respond or the circuit tests out of specification, replace the valve or repair the wiring as needed.
  7. Clear the code and perform a road test to verify the repair, ensuring the monitor runs and the code does not return.

Common Missteps When Diagnosing P2D14

  • A low circuit code does not automatically mean the valve is bad; a short to ground in the wiring is just as likely and should be ruled out first.
  • The exhaust flow control valve is often part of the exhaust gas recirculation (EGR) system or variable valve timing system, so related codes may be present and should be addressed together.
  • Some vehicles use the exhaust flow control valve for active exhaust noise reduction, so a failure may not affect performance but will trigger the light.
  • Aftermarket exhaust components or improper repairs can introduce resistance or shorts that mimic a failed valve.
  • Always check for a poor ground connection at the valve or chassis, as a bad ground can cause a low voltage code on the control circuit.

Can I keep driving with P2D14?

You can generally drive the vehicle with this code, but avoid aggressive acceleration or heavy loads until it is repaired. Prolonged driving with a faulty exhaust flow control valve may lead to increased emissions or reduced fuel economy, and if the valve is stuck closed, it could cause excessive backpressure and damage other components.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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