P247B — Exhaust Gas Temperature Out of Range #

Note: The code description may differ depending on the vehicle manufacturer. Always verify with OEM resources.

• Exhaust Gas Temperature Out of Range (Generic/Most OEMs)
• Exhaust Gas Temperature Sensor Circuit Out of Range (Ford)
• EGT Sensor Out of Range (GM/Chevrolet)
• Exhaust Temp Sensor Performance (Volkswagen/Audi)
• Exhaust Gas Temperature Sensor Malfunction (Dodge/RAM/Jeep)

Summary of DTC P247B #

The P247B diagnostic trouble code (DTC) signals that the Exhaust Gas Temperature (EGT) sensor is reading values outside the expected parameters set by the Engine Control Module (ECM). The EGT sensor monitors the temperature of gases exiting the exhaust, an essential data point for managing emission systems, protecting components like the Diesel Particulate Filter (DPF), and ensuring overall engine health. This code typically indicates either an electrical fault, a sensor malfunction, or, less commonly, a true abnormal exhaust temperature due to engine issues. Persistent presence of this code can affect emission controls and, if ignored, may lead to further complications. Accurate diagnosis is critical, as the code covers a range of possible problems from wiring issues to failed sensors.

Frequent Symptoms for DTC P247B #

When P247B is stored, your vehicle may display no obvious symptoms, or you might notice subtle changes in drivability. The ECM may activate the Check Engine Light (CEL) and, in some cases, trigger other warning lights related to the emission or exhaust system. In severe cases, performance may be reduced to protect the engine and exhaust aftertreatment systems.

• Check Engine Light illuminated
• Possible “Service Emission System” or “DPF” warning messages
• Reduced engine power (limp mode in some models)
• Decreased fuel efficiency
• Increased exhaust smoke (rare)
• Unusual exhaust odor

Probable Causes for DTC P247B #

Several issues can trigger P247B, but some are more common than others. The code generally points to an electrical or sensor-related problem, but it’s important not to overlook mechanical causes. Here’s a ranked list based on frequency:

1. Faulty Exhaust Gas Temperature (EGT) Sensor – Sensor internal failure or drift.
2. Wiring or Connector Issues – Open, shorted, corroded, or damaged wiring/connectors between the sensor and the ECM.
3. Exhaust leaks upstream of the sensor – Affects readings by allowing ambient air to enter.
4. ECM software or calibration issues – Rare but possible; incorrect thresholds or updates needed.
5. Aftermarket modifications – Non-OEM exhaust components or tuning affecting sensor function.
6. Actual exhaust temperature out of range – Resulting from engine misfire, over-fueling, or turbocharger issues.

Step-by-Step Diagnostic for Code P247B #

Diagnosing P247B requires a systematic approach to rule out the most common and easily resolved issues before moving to more complex possibilities. Here’s a proven workflow for technicians and advanced DIYers:

• 1. Scan for additional DTCs: Identify related codes (e.g., for DPF, NOx sensors, or fuel system) that may guide diagnosis.
• 2. Inspect the EGT sensor location: Visually confirm the correct sensor (there may be multiple EGT sensors in the exhaust system).
• 3. Check wiring and connectors: Look for corrosion, damage, loose pins, or melted insulation along the harness.
• 4. Monitor live data: Using a scan tool, compare EGT sensor readings to expected values and to other EGT sensors (if available).
• 5. Verify sensor operation: Perform resistance or voltage checks per OEM specifications with the engine cold and hot.
• 6. Inspect for exhaust leaks: Check for leaks upstream of the sensor, especially at welds, flanges, or gaskets.
• 7. Test ECM inputs/outputs: If wiring and sensor are good, verify the ECM is properly interpreting sensor data.
• 8. Check for technical service bulletins (TSBs): Some OEMs issue updates for known sensor or calibration issues.

Possible Repairs for DTC P247B #

Once the root cause is identified, apply the suitable remedy. Most fixes are straightforward but require attention to detail. Here are the most common repairs tied to each frequent cause:

• Replace faulty EGT sensor: If out of spec or not responding to temperature changes.
• Repair or replace damaged wiring/connectors: Restore proper continuity and insulation.
• Fix exhaust leaks: Weld, reseal, or replace affected pipes, flanges, or gaskets.
• Update ECM software/calibration: Apply OEM updates if technical bulletins or recalls exist.
• Revert aftermarket modifications: Restore OEM components if modifications interfere with sensor operation.
• Address underlying engine issues: Diagnose and repair misfires, over-fueling, or turbo faults if genuine high exhaust temps are present.

Can You Drive with Code P247B? #

Generally, you can drive short distances with P247B, but it is not recommended to ignore this code. While some vehicles may not exhibit noticeable symptoms, unresolved EGT sensor issues can lead to improper DPF regeneration or even damage to the turbocharger or catalytic converter. If your vehicle enters limp mode or additional warning lights appear, limit driving and schedule immediate repairs. Long-term driving with this fault can result in costly secondary damage, especially on modern diesel engines.

Vehicles Most Commonly Affected by P247B #

P247B is most often encountered on modern diesel vehicles equipped with advanced emission aftertreatment systems, though it can appear on some gasoline models. The following brands and models are frequently associated with this code:

• Ford Super Duty (F-250, F-350, F-450) — especially with Powerstroke engines
• Chevrolet Silverado/GMC Sierra HD — Duramax diesels
• Dodge/RAM 2500, 3500 — Cummins diesels
• Volkswagen Touareg, Audi Q7 — V6 TDI engines
• Jeep Grand Cherokee EcoDiesel
• Some BMW and Mercedes-Benz BlueTEC diesel models
• Various Freightliner and Isuzu medium-duty trucks

Common Mistakes & Best Practices for P247B #

Misdiagnosis of P247B can lead to wasted time and money. Avoid these pitfalls and follow professional best practices for accurate repairs:

• Replacing the sensor without checking wiring and connectors first
• Confusing EGT sensors with oxygen (O2) or NOx sensors — always verify sensor location
• Failing to check for exhaust leaks upstream of the affected sensor
• Ignoring related codes or symptoms that could point to a root cause elsewhere
• Neglecting to clear codes and retest after repairs to confirm resolution
• Using non-OEM replacement parts that may not meet proper specifications

Express FAQ: P247B #

Q: Will P247B cause my vehicle to fail emissions testing?
A: Yes, an active P247B code will usually trigger a Check Engine Light and prevent your vehicle from passing an emissions test until it’s resolved and the readiness monitors reset.

Q: Can I clean an EGT sensor to fix P247B?
A: In most cases, EGT sensors are sealed, non-serviceable components. Cleaning is rarely effective; replacement is the recommended solution if the sensor is faulty.

Q: Does P247B mean my DPF is damaged?
A: Not directly. However, if the EGT sensor issue persists, it may prevent proper DPF regeneration and could eventually harm the DPF or other exhaust components.