The OBD-II (On-Board Diagnostics) Code P24F3 relates to the reductant tank temperature/fuel temperature correlation. This code is associated with emission systems, specifically with the Diesel Exhaust Fluid (DEF) system. When this code appears, it indicates that there is a problem with the correlation between the temperature of reductant tank and fuel. Defective sensors, wiring, and electrical components may cause this problem. In this article, we will discuss what OBD-II Code P24F3 means, potential symptoms, and how to diagnose and repair the issue.
What is the Reductant Tank Temperature/Fuel Temperature Correlation?
The reductant tank temperature/fuel temperature correlation is a process that DEF systems use to calculate the temperature difference between the DEF and the fuel. This calculation is crucial because, at low fuel temperatures, the DEF will crystallize, leading to blockage in the DEF system. The reductant tank temperature/fuel temperature correlation also triggers emissions-related actions when the observed temperature difference is beyond the acceptable range. These actions could include setting fault codes like OBD-II Code P24F3.
What are the Symptoms of OBD-II Code P24F3?
Usually, OBD-II Code P24F3 activates the Check Engine Light (CEL). Other symptoms may include a power loss, decreased fuel economy, and the DEF related warning message on the dashboard. The warning message may indicate that the DEF system requires attention or that the DEF level is low. The warning message typically cancels after refilling the DEF reservoir, but the CEL may remain illuminated. Keep in mind that other OBD-II codes can activate the CEL and cause similar symptoms.
How to Diagnose OBD-II Code P24F3
Diagnosing OBD-II Code P24F3 requires a professional with the proper diagnostic equipment. One of the diagnostics that the professionals will carry out will involve verifying the system’s temperature sensors. Temperature sensors are placed within the DEF system to monitor and regulate the DEF temperature and provide feedback to the Electronic Control Module (ECM). If there is an incorrect reading on the sensors, a professional should make necessary repairs to ensure they function correctly.
The professional should also examine the DEF system for any signs of damage or corrosion. As the DEF system reaches the end of its lifespan, damage can occur in the form of leaks or clogs due to crystallization or contamination. Fuel contamination can cause the DEF spray nozzle and system tank to clog, leading to DEF system failure. In the case of contamination, a mechanic should drain the DEF reservoir, inspect for damage, clean, and then refill with fresh DEF.
Finally, the professional should upgrade the vehicle software to the latest version. OE manufacturers will issue software updates for certain vehicle models for enhancement on weak points or to correct software bugs. A software update should occur before any other repairs.
If a professional diagnoses and repairs all necessary repairs on the DEF system and associated circuits failed to eliminate the code, they will replace the ECM—the vehicle’s primary computer responsible for the operation of all the electronic and electrical components in the system.
How to Repair OBD-II Code P24F3
Repairing OBD-II Code P24F3 requires replacing the faulty component causing the issue. Depending on the underlying problem, expected repairs may include repairing damaged wiring or replacing sensors, cleaning or draining the reductant tank, or, as noted above, replacing the ECM. Once the underlying problem is repaired, the CEL will disappear. It is essential to double-check and confirm the repair to ensure that the CEL does not relight. After testing, upgrades to the vehicle software may improve system performance and fuel efficiency.
FAQs
Q: Can OBD-II Code P24F3 disconnect?
A: No. For the most part, OBD-II codes will require technicians and diagnostic equipment for repairs. While there are a few rare and temporary codes that may resolve on their own, the majority of codes will persist and require repairs to ensure the proper functioning of the system.
Q: What is reductant?
A: Reductants react with pollutants in the exhaust stream and convert them into harmless levels of nitrogen, oxygen, and water vapor. For diesel engines, DEF is the most commonly used reductant.
Q: I refilled the DEF tank, and the warning light is still on. What can I do to turn it off?
A: Depending on your vehicle, you may have to complete a certain number of miles driven before the warning light clears. If it does not, or if there are other concerns, it is best to have the system diagnosed to determine the problem.
Q: Do I need professional help to replace sensors?
A: We always recommend professional replacement of sensors and replacement of most components within the DPF or DEF systems. These systems are essential to meeting emissions regulations, and the incorrect installation or diagnosis can result in more in-depth and costly repairs.
Q: Should I diagnose and repair the OBD-II Code P24F3 problem myself?
A: We advise against diagnosing and repairing the issue yourself. As we have discussed, the causes of OBD-II Code P24F3 could be various, and some of the repairs are better left to professionals with the right equipment, skill, and knowledge base to pinpoint the problem accurately.
Case study
A BMW X3 diesel had intermittent failures of the DEF system, with an OBD-II Code P24F3 stored. The technician tested sensors through a live data check and discovered a discrepancy between the reductant tank temperature and the fuel tank temperature. The technician scrutinized the fuel temperature sensor and found that the vehicle’s fuel temperature sensor, which the ECM utilizes for determining correlation with the temperature sensor on the DEF system, had failed. The technician replaced the fuel temperature sensor, cleared out the codes, and then carried out an extended test drive to validate repairs.
Conclusion
OBD-II Code P24F3 is an indication of a problem with the Diesel Exhaust Fluid (DEF) system. When you notice the Check Engine Light alongside the DEF-related warning message, it is a sign that there is a problem with the reductant tank temperature/fuel temperature correlation. You will need to take the car to a professional to diagnose the issue and carry out any necessary repairs. Always ensure you have the right equipment, knowledge, and skill base before attempting any diagnostics and repairs to avoid further destruction and dangerous situations.