P247B — Exhaust Gas Temperature Out of Range

The diagnostic trouble code P247B indicates an issue related to the exhaust gas temperature sensor or its circuit, where the measured temperature exceeds or drops below the expected range. This code is generated by the vehicle’s engine control unit (ECU) when it detects abnormal readings from the exhaust gas temperature sensor, which monitors the temperature of the exhaust gases in specific components such as the catalytic converter or diesel particulate filter (DPF). It is important to note that the label for this code may vary between different vehicle manufacturers.

System affected: Exhaust Gas Temperature Sensor / Monitoring System
Severity: Moderate to potentially severe if unresolved
Main symptoms: Engine warning light, reduced performance, possible DPF issues
Driveability: Limited, potential for increased emissions or component damage

Manufacturer variations for trouble code P247B

Different vehicle manufacturers may assign unique labels or descriptions to the P247B code based on their diagnostic protocols. It’s essential to consult the specific OEM (Original Equipment Manufacturer) documentation for precise diagnostic information. Common variations include:

Ford: P247B – Exhaust Gas Temperature Sensor Circuit High (or Low) Response
BMW: 4F87 – Exhaust Gas Temperature Sensor Out of Range
Volkswagen / Audi / SEAT / Škoda: P247B may be referenced as part of « Exhaust Gas Temperature Sensor Malfunction »
Mercedes-Benz: Specific label not universally assigned but related to Exhaust Gas Temp Sensor readings

What does trouble code P247B mean?

In simple terms, P247B signals that the vehicle’s ECU has detected an abnormal exhaust gas temperature reading. This sensor is responsible for providing real-time temperature data of the exhaust gases — particularly around critical emission control components like the catalytic converter or diesel particulate filter (DPF). If the sensor reports a temperature that is significantly higher or lower than expected, it triggers this diagnostic trouble code.

The main cause of this error is usually a malfunctioning sensor, a faulty circuit, or issues related to components that influence exhaust temperature, such as the DPF or catalytic converter. The code tends to appear during driving conditions that involve active regeneration of the DPF, or during abnormal engine operation, and it can sometimes be a sign of underlying engine or emission system issues.

Severity and risks of trouble code P247B

This code shouldn’t be ignored, as persistent abnormal exhaust gas temperatures can accelerate component wear or cause damage. Excessively high temperatures might lead to damage to the catalytic converter, DPF, or exhaust manifold, while abnormally low temperatures could interfere with emission control and fuel efficiency. If unaddressed, this can result in increased emissions, potential engine performance issues, or costly repairs.

Is the vehicle safe to drive with P247B? Limited — you can usually drive for a short period, but it is recommended to have the vehicle diagnosed and repaired promptly to avoid further damage or failure of critical components.

Symptoms of trouble code P247B

The presence of P247B may be accompanied by various symptoms. Since the issue relates to exhaust gas temperature, symptoms could vary based on severity and the specific underlying cause. Typical signs include:

Illumination of the **Check Engine Light** or emission warning light
Engine shuddering or rough idle in some cases
Reduced engine performance or power loss
Increased fuel consumption
Unusual exhaust smells or smoke
Possible difficulty during active regeneration of the DPF

Most likely causes of trouble code P247B

Understanding what triggers P247B helps in pinpointing the repair. The causes are typically linked to sensor issues, circuit problems, or related components. The most common causes include:

Faulty Exhaust Gas Temperature Sensor (EGT Sensor): The sensor itself may be defective, damaged, or has failed over time.
Wiring or Connector Issues: Corrosion, damaged wiring, or poor connections in the sensor circuit can lead to false or out-of-range readings.
Exhaust System Issues: Blockages, leaks, or damage within components like the catalytic converter or DPF may lead to abnormal temperature readings.
Exhaust Gas Temperature Sensor Circuit Short or Open: Electrical faults within the sensor circuit can trigger the code.
Related Emission Control System Failures: Problems with other parts of the exhaust or emission system that influence temperature or sensor readings.

How to diagnose trouble code P247B

Diagnosing P247B involves a structured approach to identify whether the sensor, wiring, or affected components are at fault. To ensure safety and accuracy, follow these steps:

Visual Inspection: Check the wiring harness and connector associated with the exhaust gas temperature sensor. Look for corrosion, damage, or loose connections.
Live Data Monitoring: Use an OBD-II scanner or diagnostic tool capable of reading live sensor data. Confirm whether the temperature readings are consistent with operating conditions.
Compare Sensor Readings: Cross-reference the sensor data with expected temperature ranges during different engine states (idle, acceleration, regeneration phases).
Check for Wiring Continuity: Perform continuity tests on the sensor wiring circuits to rule out shorts or opens.
Verify Related Components: Assess the health of components like the catalytic converter and DPF, especially if temperatures are abnormal.
Review Freeze Frame Data: Check the stored data for patterns or conditions when the fault was recorded, providing clues to internal issues.

Possible repairs for trouble code P247B

If diagnosis confirms a fault, repairs will typically involve replacing or repairing the faulty parts. The scope of repairs can vary from simple to more complex procedures:

Replacing the Exhaust Gas Temperature Sensor: Usually a straightforward repair, suitable for DIY or professional technicians.
Repairing Wiring or Connectors: Restoring integrity of the electrical circuit, including cleaning or replacing damaged wiring or connectors, is often a basic repair.
Addressing Exhaust System Issues: Repairing or replacing damaged catalytic converters, DPFs, or exhaust pipes may be needed if these components are contributing to abnormal temperatures. This is typically a professional repair.
Ensuring Proper Sensor Operation: Once repairs are made, clear the codes and verify sensor readings and overall system operation.

Vehicles commonly associated with trouble code P247B in Europe

The P247B code can appear across various vehicle brands, especially those equipped with advanced emission control systems. While the exact occurrence varies, vehicles from the following brands are more frequently associated with exhaust temperature sensor issues:

Volkswagen Group (VW, Audi, SEAT, Škoda): Especially models with diesel engines and DPF systems.

Ford: Particularly turbocharged diesel models.

BMW: Diesel engine variants with exhaust aftertreatment systems.

Mercedes-Benz: Emission systems with exhaust temperature monitoring.

Frequent mistakes with trouble code P247B

Diagnosing and repairing P247B requires careful attention. Common pitfalls include:

Failing to verify wiring harness integrity before replacing the sensor.
Ignoring the possibility of exonerating other components like the DPF or catalytic converter as root causes.
Replacing a sensor without confirming the sensor’s actual malfunction — potentially chasing a false fault.
Overlooking the importance of live data analysis, which can mask underlying issues.
Using generic or incompatible replacement parts, leading to persistent faults.

Quick FAQ — trouble code P247B

Can this code disappear on its own? In some cases, if the issue was caused by a temporary glitch or sensor anomaly, clearing the code might temporarily resolve it. However, if underlying causes persist, the code is likely to return.

Can I keep driving? The vehicle can often be driven safely for a limited time, but continued driving without fixing the issue risks further damage to exhaust components or emission systems. Professional diagnosis is recommended.

Why does the code return after clearing? Persistent faults, such as wiring issues, defective sensors, or damage to exhaust components, cause the code to reappear once the ECU tests the sensor again during subsequent drives.