P2C48

Exhaust Gas Recirculation Sensor A Circuit Low

P2C48 is a generic OBD-II powertrain diagnostic trouble code: Exhaust Gas Recirculation Sensor A Circuit Low. 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
P2C48
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P2C48 means

P2C48 is set when the ECM detects that the voltage from EGR sensor circuit A is below the calibrated minimum limit. EGR sensors monitor flow, differential pressure, or valve position depending on system design, providing feedback the ECM uses to modulate exhaust gas recirculation for emissions and combustion control.

A low circuit signal prevents accurate EGR control. The ECM may disable EGR operation and run in open-loop mode, which typically increases NOx emissions and may affect fuel economy. On diesels with tight emissions requirements, this can also influence regeneration scheduling.

Common causes include a short to ground on the signal wire, a failed sensor producing a sub-minimum voltage output, loss of the 5V reference supply, or connector damage. Inspect the EGR valve harness and associated pressure or position sensor before replacing components.

Common causes

Most-frequently reported root causes when P2C48 is logged.

  • 1
    Sensor signal wire shorted to ground.
  • 2
    Failed EGR position or differential pressure sensor.
  • 3
    Open 5V reference supply circuit to the sensor.
  • 4
    Corroded sensor connector allowing moisture ingress.
  • 5
    Damaged wiring harness routed near hot exhaust components.
  • 6
    Faulty ECM 5V reference rail affecting sensor.
  • 7
    EGR valve seized causing sensor over-range reading.

Symptoms drivers notice

MIL illuminated.
EGR system disabled, running in open-loop mode.
Possible increase in exhaust emissions or failed emissions test.
Slightly reduced fuel economy in some operating conditions.
Possible rough idle if EGR feedback is critical to idle calibration.

How to diagnose P2C48

A typical diagnostic flow when this code is present.

  1. 1
    Retrieve all DTCs and note any companion EGR or sensor supply codes.
  2. 2
    Check live data for EGR sensor A voltage; confirm it reads below expected minimum.
  3. 3
    Inspect the EGR sensor connector and wiring for damage, corrosion, or heat damage.
  4. 4
    Measure 5V reference at the sensor connector with ignition on.
  5. 5
    Check signal wire continuity and test for short to ground.
  6. 6
    Substitute a known-good sensor to confirm or rule out sensor failure.
  7. 7
    Inspect ECM connector pins for corrosion if fault persists after sensor and wiring checks.

Vehicles where we've handled P2C48

Platforms in our catalogue with confirmed P2C48 coverage.

BMW 320D
2016

Related powertrain codes

Frequently asked questions

Does P2C48 affect drivability much?

In many cases drivability is only mildly affected, but NOx emissions will rise and the MIL will remain on until repaired.

Can a clogged EGR valve cause this code?

A mechanical blockage alone does not typically cause a low circuit electrical fault; wiring and sensor issues are more likely.

Which sensor does circuit A refer to?

Circuit A designates the primary EGR sensor in systems with multiple sensors; check the vehicle-specific wiring diagram to identify the exact sensor location.

Will disabling EGR fix the fault?

Physically disabling EGR does not resolve the electrical fault; the ECM will still detect the low circuit signal and keep the MIL on.

Disabling P2C48 in software

RaceTune can permanently disable P2C48 — 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 P2C48 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

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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