P245B

Gas Recirculation Cooler Bypass Control Circuit Range/Performance

P245B is a generic OBD-II powertrain diagnostic trouble code: Gas Recirculation Cooler Bypass Control Circuit Range/Performance. It is logged by the engine control unit when the dpf monitor detects that a specific fault threshold has been exceeded — typically resulting in the malfunction-indicator lamp (MIL / check-engine light) being illuminated.

Code
P245B
Group
Powertrain
System
DPF
Severity
Warning (MIL on, possible limp mode)
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What P245B means

P245B is set when the ECM determines that the EGR cooler bypass control valve is stuck in the open position and cannot be commanded closed. EGR systems on many modern diesel and gasoline engines include a bypass valve that diverts exhaust gas around the EGR cooler under certain conditions, such as during cold starts when cooled EGR would reduce combustion temperatures excessively.

A stuck-open bypass valve means recirculated exhaust gas is always routed around the cooler rather than through it, returning hot, uncooled gas to the intake. This raises intake charge temperature and can increase NOx emissions, reduce EGR effectiveness, and potentially cause thermal stress on intake components designed for cooled EGR flow.

Diagnosis should confirm whether the valve is mechanically stuck (carbon fouling, seized actuator) or whether the fault is electrical (actuator wiring, solenoid, or ECM output). Actuator testing via the scan tool while monitoring position feedback distinguishes the two. Cleaning the bypass valve and cooler passages is often necessary on high-mileage engines before replacing the actuator.

Common causes

Most-frequently reported root causes when P245B is logged.

  • 1
    Carbon deposit buildup mechanically jamming the EGR cooler bypass valve in the open position.
  • 2
    Seized or failed bypass valve actuator (electric motor or vacuum).
  • 3
    Broken or disconnected valve linkage preventing closure.
  • 4
    Wiring fault preventing the ECM from commanding the valve closed.
  • 5
    Faulty bypass valve position sensor reporting open when closed.
  • 6
    EGR cooler bypass valve damaged or warped by excessive heat.
  • 7
    Faulty ECM output driver for the bypass control valve.

Symptoms drivers notice

MIL illuminated.
Elevated intake air temperature under load.
Possible increase in NOx emissions.
Potential mild power reduction or rough running from suboptimal EGR temperature.
Possible smoke from exhaust if hot EGR disrupts combustion quality.

How to diagnose P245B

A typical diagnostic flow when this code is present.

  1. 1
    Connect a scan tool and read all DTCs and relevant EGR live data.
  2. 2
    Use the scan tool actuator test to command the bypass valve open and closed while observing feedback.
  3. 3
    Inspect the EGR cooler bypass valve and linkage for carbon fouling, physical damage, or seizure.
  4. 4
    Check the bypass valve actuator wiring and connector for damage or corrosion.
  5. 5
    Measure actuator supply voltage and control signal voltage during a command cycle.
  6. 6
    Clean the bypass valve and actuator mechanism if heavy carbon deposits are found.
  7. 7
    Replace the bypass valve or actuator if cleaning does not restore movement.

Vehicles where we've handled P245B

Platforms in our catalogue with confirmed P245B coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

What does the EGR cooler bypass valve actually do?

It routes exhaust gas either through the EGR cooler (for cooled EGR during normal operation) or around it (for hot EGR during cold starts to aid warm-up and catalyst light-off).

Is P245B a common fault on high-mileage diesel engines?

Yes. Carbon accumulation in the EGR circuit is very common on diesel engines and frequently causes bypass and switching valves to stick.

Can I drive with P245B active?

Short-term driving is generally possible, but continuous uncooled EGR may raise intake temperatures and long-term NOx levels; repair is recommended.

Does cleaning the valve always fix P245B?

If the root cause is carbon fouling, cleaning often resolves the fault; electrical actuator faults or mechanically damaged valves require replacement.

Disabling P245B in software

RaceTune can permanently disable P245B — 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 P245B 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 EDC17C50 verified 1 software version
  • Bosch EDC17CP09 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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