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)
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What P045E means

DTC P045E is set when the PCM/ECM detects a higher-than-expected voltage on the control circuit of the EGR B actuator. The suffix B designates the second EGR actuator circuit where a dual-EGR or split-circuit arrangement is used. A high voltage condition typically indicates an open circuit in the return or ground path, or an internal short to a voltage source within the actuator.

The EGR system recirculates a metered portion of exhaust gas back into the intake to reduce peak combustion temperatures and lower NOx emissions. When the EGR B actuator cannot be controlled accurately, the PCM will store P045E and may substitute a default EGR duty cycle or fully disable EGR, leading to elevated NOx output and possible MIL illumination.

Diagnosis should start with visual inspection of the EGR B actuator harness and connector, followed by voltage and resistance checks at the PCM connector to confirm whether the fault is in the wiring or inside the actuator itself.

Common causes

Most-frequently reported root causes when P045E is logged.

  • 1
    Open circuit in the EGR B actuator control wire between the PCM and the actuator.
  • 2
    Damaged or corroded terminals at the EGR B actuator connector.
  • 3
    Short to voltage in the EGR B control circuit wiring harness.
  • 4
    Failed EGR B actuator with an open internal winding.
  • 5
    PCM driver circuit failure for the EGR B output.
  • 6
    Chafed wiring contacting a voltage reference wire in the same harness bundle.

Symptoms drivers notice

MIL illuminated with P045E stored.
Possible increase in NOx emissions due to reduced or absent EGR flow.
Slight reduction in fuel economy under part-load conditions.
Possible rough idle if EGR B default position affects intake charge dilution.
Emissions test failure on vehicles where EGR is required for compliance.

How to diagnose P045E

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and record freeze-frame data to understand operating conditions when the fault was set.
  2. 2
    Inspect the EGR B actuator connector and wiring harness for visible damage, corrosion, or chafing.
  3. 3
    Measure the supply voltage and ground at the EGR B actuator connector with the ignition on.
  4. 4
    Measure resistance of the EGR B actuator coil and compare to specification.
  5. 5
    Back-probe the PCM connector for the EGR B control circuit and check for a high voltage condition with the circuit unplugged from the actuator.
  6. 6
    Replace the EGR B actuator if wiring and PCM output check within specification.
  7. 7
    Clear DTCs and perform a drive cycle to verify the repair.

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 the B suffix mean in P045E?

SAE uses A, B, C suffixes to distinguish multiple instances of the same component type. EGR B refers to the second EGR control circuit on vehicles with dual or staged EGR systems.

Is P045E a hard or intermittent fault?

It can be either. Check the fault counter in the scan tool to distinguish a confirmed continuous fault from an intermittent one caused by vibration or temperature.

Can a clogged EGR valve cause P045E?

Carbon buildup alone will not cause a circuit high code; P045E is an electrical fault. Mechanical restriction would typically set a position or flow rationality code instead.

Will P045E cause limp mode?

On most applications the PCM stores P045E and illuminates the MIL but continues operating without entering limp mode, as EGR is not critical for basic engine operation.

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.

ECUs with a P045E disable in our catalogue

Confirmed coverage from our recipe database — we support many more families. Upload your file and our identifier will match it automatically.

  • Bosch EDC17C74 verified 1 software version

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.

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