P24B7

Diesel Particulate Filter Differential Pressure Sensor Circuit High

P24B7 is a generic OBD-II powertrain diagnostic trouble code: Diesel Particulate Filter Differential Pressure Sensor 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
P24B7
Group
Powertrain
System
Powertrain
Severity
Warning (MIL on)
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What P24B7 means

P24B7 is set when the ECM detects that the signal voltage from the diesel particulate filter differential pressure sensor is above the maximum expected operating range. Like P24B6, this is an electrical circuit fault rather than a performance issue. A high circuit voltage typically indicates an open circuit in the signal or ground wire, or a short to a power supply line.

When the sensor signal wire is open or the sensor ground is lost, the ECM input is pulled up by internal bias resistors, resulting in a voltage reading that exceeds the valid sensor range. A sensor that has internally failed open will produce the same effect. This fault disables accurate DPF soot load monitoring.

As with P24B6, the loss of differential pressure feedback compromises the DPF regeneration management system. The ECM may fall back to a fixed soot model. Diagnosis should focus on the sensor wiring continuity and connector integrity before replacing the sensor.

Common causes

Most-frequently reported root causes when P24B7 is logged.

  • 1
    Open circuit in the sensor signal wire between the differential pressure sensor and the ECM.
  • 2
    Loss of ground reference at the differential pressure sensor.
  • 3
    Short to power supply on the sensor signal wire pulling the signal above maximum range.
  • 4
    Defective differential pressure sensor with an internally open signal element.
  • 5
    Broken or corroded pin in the sensor connector or ECM connector.
  • 6
    Wiring harness damage causing an open circuit due to heat, vibration, or abrasion.
  • 7
    Moisture ingress into the sensor or connector causing intermittent open circuit conditions.

Symptoms drivers notice

MIL illuminated on the instrument cluster.
Differential pressure sensor reading at maximum scale or an error value on the scan tool.
DPF soot load estimate unavailable or using default fallback values.
DPF regeneration may be inhibited or unreliable.
No immediate drivability impact in most cases.

How to diagnose P24B7

A typical diagnostic flow when this code is present.

  1. 1
    Read all DTCs and review freeze-frame data to establish conditions when the fault was set.
  2. 2
    Inspect the sensor wiring harness and connector for open circuits, broken wires, or corrosion.
  3. 3
    With the ignition on and sensor connected, measure the signal voltage; a reading above maximum confirms the circuit high condition.
  4. 4
    Disconnect the sensor connector and check for continuity on the signal and ground wires from connector to ECM.
  5. 5
    Check for a short to battery voltage on the signal wire using a multimeter.
  6. 6
    Replace the differential pressure sensor if the wiring continuity checks out and the fault persists with a new sensor.
  7. 7
    After repair, clear DTCs and verify the sensor signal reads within the expected range across engine operating conditions.

Related powertrain codes

Frequently asked questions

What is the difference between P24B6 and P24B7?

P24B6 indicates the sensor signal is below the minimum operating voltage (typically caused by a short to ground), while P24B7 indicates the signal is above the maximum voltage (typically caused by an open circuit or short to power).

Can a disconnected sensor cause P24B7?

Yes. An unplugged or disconnected sensor connector is one of the most common causes of a circuit high fault, as the ECM input floats to a high voltage when the sensor is absent.

Could a faulty ECM cause P24B7?

It is possible but uncommon. Always confirm the sensor wiring and sensor itself are functioning correctly before suspecting the ECM.

Will P24B7 cause the DPF to fail prematurely?

It can contribute to DPF damage if undetected soot accumulation occurs because the ECM is operating without accurate differential pressure feedback. Timely repair is important.

Disabling P24B7 in software

RaceTune can permanently disable P24B7 — 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.

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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