P045E

Exhaust Gas Recirculation B Control Circuit High

P045E is a generic OBD-II powertrain diagnostic trouble code: Exhaust Gas Recirculation B Control Circuit High. It is logged by the engine control unit when the powertrain monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P045E
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on, possible limp mode)
Need P045E disabled?
RaceTune permanently disables any OBD-II trouble code on supported ECUs — for motorsport, off-road, and export use.
→

What P045E means

P045E indicates that the powertrain control module has determined the exhaust gas recirculation (EGR) B valve appears to be stuck in the open position. The B designation refers to a second EGR channel or a particular stage of a staged EGR system. Rather than an open- or short-circuit fault, this is a functional rationality code: the ECM commands the valve closed but the resulting flow, position feedback, or downstream pressure indicates the valve is not sealing.

The EGR system routes a metered portion of exhaust gas back into the intake to lower peak combustion temperature and reduce NOx. When the B valve stays open, excess exhaust dilutes the intake charge at idle and low load, upsetting combustion. The most common cause is carbon and soot accumulation on the valve seat or pintle that physically prevents full closure, though a failed actuator, position sensor, or seized linkage can also be responsible.

Because a valve stuck open produces real driveability problems, this code should be addressed promptly. Diagnosis begins with inspecting the valve for carbon fouling and verifying, with a bi-directional test and live data, whether it can actually close when commanded before condemning the actuator.

Common causes

Most-frequently reported root causes when P045E is logged.

  • 1
    Carbon or soot buildup on the EGR B valve seat or pintle preventing full closure.
  • 2
    Failed or weak EGR B actuator unable to drive the valve closed.
  • 3
    Seized or binding valve shaft or linkage holding the valve open.
  • 4
    Faulty EGR B position sensor reporting the valve as open incorrectly.
  • 5
    Broken return spring or damaged internal valve mechanism.
  • 6
    Clogged or restricted EGR passages disturbing the flow the ECM expects.
  • 7
    Damaged wiring or connector causing the actuator to hold an open position.

Symptoms drivers notice

Malfunction indicator lamp illuminated with P045E stored.
Rough, unstable, or surging idle from excess exhaust dilution.
Hesitation, stumble, or lack of power at low load.
Increased exhaust smoke or noticeable exhaust smell.
Reduced fuel economy and possible limp mode on some calibrations.
Emissions test failure due to disturbed EGR control.

How to diagnose P045E

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and review freeze-frame data for the conditions when the code set.
  2. 2
    Compare commanded EGR B position against actual position or flow feedback in live data.
  3. 3
    Use a bi-directional scan tool test to command the EGR B valve open and closed and observe response.
  4. 4
    Remove or inspect the EGR B valve for carbon buildup, sticking, or debris preventing closure.
  5. 5
    Clean carbon deposits and verify the valve seats fully and moves freely before further repair.
  6. 6
    Test the actuator and position sensor wiring for continuity, shorts, and correct voltage.
  7. 7
    Replace the EGR B valve or actuator if it cannot achieve full closure after cleaning.

Vehicles where we've handled P045E

Platforms in our catalogue with confirmed P045E coverage.

AUDI A4 20D

Related powertrain codes

Frequently asked questions

What does P045E actually mean?

It means the ECM has determined the second EGR (B) valve is stuck open and not sealing when commanded closed, which is a mechanical or rationality fault rather than a simple wiring fault.

Can I clean the valve instead of replacing it?

Often yes; carbon fouling is the most common cause of a stuck-open EGR valve, and thorough cleaning frequently restores proper closure.

Why does the engine idle poorly with this code?

A valve stuck open lets exhaust gas into the intake at idle and low load, diluting the charge and causing rough running, hesitation, or stalling.

Should I keep driving with P045E?

It is best to repair it promptly because the driveability issues can worsen and some vehicles enter a reduced-power limp mode.

Disabling P045E in software

RaceTune can permanently disable P045E — and any other OBD-II diagnostic trouble code — on every ECU family we support. The monitor is disabled inside the ECU itself, so the fault stops being logged: the warning light stays off and the engine never enters limp mode for this code. The change is tied to your exact software version.

Permanent
The monitor is disabled in the ECU itself — not just cleared. It cannot return.
Tailored to your file
Each patch is matched to your specific software version — never a one-size-fits-all file.
Reversible
The original file is always preserved. Reflash the stock to return the ECU to factory state.

ECU families we can disable P045E on

We hold the DaVinci A2L disable definitions for these families, so the exact P045E path and mask addresses are mapped. verified marks a confirmed disable definition. We support many more — upload your file and our identifier will match it automatically.

  • Bosch EDC17C66 verified
  • Bosch EDC17C74 verified
  • Bosch MD1CP002 verified
  • Bosch MD1CP004 verified
  • Bosch MD1CS001 verified

Software modifications affect emissions compliance and are not road-legal in many jurisdictions. RaceTune service files are intended for motorsport, off-road, and export use.

Got P045E in your scan?

Upload your ECU file — we'll identify the exact software version and confirm whether a disable is available for your car.

Upload your file