Fuel and air

P016E — Fuel Rail Pressure Control at Limit – Pressure Too High

Severity: medium Drive with care, to a shop

What P016E means

The engine control module holds fuel pressure with a closed loop: it compares the rail pressure sensor reading to a target and adjusts the regulator or volume control valve. P016E sets when that control has reached its end of travel and actual pressure is still too high. The cause can be truly excessive pressure or a false sensor signal.

Symptoms

  • Check Engine light on
  • Rough idle
  • Hesitation or stumbling under load
  • Reduced power
  • Poor fuel economy or rich running
  • Hard or long starting
  • Limp mode with limited power

Possible causes

  1. Faulty fuel rail pressure sensor
  2. Faulty pressure regulator or volume control valve
  3. Fuel pump (low or high pressure) delivering excess pressure
  4. Clogged or restricted return line or filter
  5. Wiring or connector fault in the fuel pressure circuit
  6. Worn or faulty high-pressure pump
  7. Excessive injector return flow (internal leakage)

How to diagnose

  1. Scan for codes and freeze frame data, and note any other fuel system codes
  2. Compare specified and actual rail pressure at cranking, idle and under load
  3. Check low-pressure supply pressure and volume: pump, filter, lines
  4. Inspect wiring and connectors at the pressure sensor and regulator, checking power and ground
  5. Check the sensor reading with the engine off and compare against a mechanical gauge
  6. Test regulator or control valve operation against the ECM command
  7. Inspect the return line for restrictions or kinks
  8. Where applicable, measure injector return flow

Common fixes

  • Replace the fuel pressure sensor
  • Replace the pressure regulator or volume control valve
  • Repair damaged wiring or connectors
  • Clean or replace the return line and filter
  • Replace the fuel pump or high-pressure pump if confirmed faulty

Questions and answers

What does P016E mean?

The ECM can't lower fuel rail pressure to the target value, so the control has reached its limit with pressure still too high. The cause may be the sensor, regulator, pump or wiring.

Can I drive with P016E?

Only briefly, to reach a shop. The engine may stumble or lose power, and prolonged high pressure wears fuel system parts.

Where do I start diagnosing P016E?

Compare target and actual rail pressure and check the pressure sensor and its wiring. If those are fine, check the regulator, low-pressure supply and return line.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.