Fault Code SPN 3713: What It Means and How to Fix It
Fault Code SPN 3713/FMI 31 indicates that a High Idle Regeneration (HIR) was aborted due to low regeneration temperature in the Diesel Oxidation Catalyst (DOC). This is a serious issue that requires immediate attention.
Urgency and Driving Considerations
If you get this fault code, do not continue driving the vehicle. Park it in a safe location and contact your dealer or a qualified mechanic right away. Continuing to operate the vehicle with an aborted regeneration can lead to more severe problems like clogged DPF filters.
In our workshop, we've encountered Fault Code SPN 3713 quite frequently across various makes and models. Just last week, we had a Mercedes Sprinter van come in with the check engine light on and SPN 3713 stored in the fault memory. After diagnosing, we found an exhaust leak just before the DOC causing low regeneration temperatures. The week before, a Volkswagen Crafter had the same issue, but it turned out to be a faulty EGT sensor. We've also worked on several Renault and Peugeot diesel vans with SPN 3713 triggered by charge air cooler leaks. While this fault code isn't make-specific, in our experience it does seem to pop up more often on European diesel vans and trucks, likely due to their prevalence in commercial fleets here. Regardless of make, though, we always start by checking for air and exhaust leaks, as those are the most common causes we've found.
Code Details
SPN 3713/FMI 31 is a standard J1939 diagnostic trouble code that applies to many makes and models of diesel trucks and equipment. The specific parts involved are:
- Diesel Oxidation Catalyst (DOC): Converts carbon monoxide and unburned hydrocarbons into carbon dioxide and water
- Diesel Particulate Filter (DPF): Traps and holds diesel particulate matter (soot)
- Exhaust Gas Temperature Sensors: Monitor temperatures in the DOC and DPF
During regeneration, the DOC inlet should reach at least 572°F (300°C) and the DOC outlet should get to 1022°F (550°C). If these temperatures are not achieved, the regeneration will abort and set SPN 3713.
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Common Causes
Some common reasons why a regeneration may abort with SPN 3713 include:
- Leaking or damaged charge air cooler (CAC) hoses
- Exhaust leaks before or around the DOC/DPF
- Faulty exhaust gas temperature sensors
- Low coolant level or coolant leaks
- Defective hydrocarbon (HC) doser
Diagnosis Steps
To diagnose SPN 3713, follow this procedure:
- Check for visible exhaust leaks, especially around the DOC/DPF area. Repair any leaks.
- Inspect charge air cooler hoses for damage. Replace as needed.
- Verify coolant level is correct. Fix any coolant leaks.
- Using a scan tool, review live data from the EGT sensors. Replace faulty sensors.
- If no other issues are found, remove and inspect the HC doser. Clean or replace it.
Repair Costs
The cost to repair this issue depends on the root cause. Some approximate parts costs are:
- EGT sensors: $200-300 USD ($180-270 EUR) each
- HC doser: $800-1200 USD ($720-1080 EUR)
- Charge air cooler hoses: $150-300 USD ($135-270 EUR)
- Coolant: $25-50 USD ($23-45 EUR) per gallon (3.8 L)
Labor time is typically 3-8 hours depending on what parts need replacement. Total repair costs can range from a few hundred to several thousand dollars/euros.
To help prevent SPN 3713, ensure regular maintenance is performed, including:
- Checking coolant level
- Inspecting charge air cooler hoses
- Monitoring for exhaust leaks
Some other codes commonly seen along with SPN 3713 are:
- SPN 3556 (Aftertreatment 1 Outlet Gas Temperature Sensor)
- SPN 3216 (Aftertreatment 1 Intake Gas Temperature Sensor)
- SPN 4094 (NOx limits exceeded due to Insufficient Reagent Quality)
Proper diagnosis and repair of SPN 3713 requires following the troubleshooting steps in order. Overlooking issues like charge air and coolant leaks can result in repeat failures. When in doubt, consult the manufacturer's service information for model-specific details.
Frequently Asked Questions About SPN 3713
What does SPN 3713 mean?
SPN 3713/FMI 31 indicates that a High Idle Regeneration (HIR) was aborted due to low regeneration temperature in the Diesel Oxidation Catalyst (DOC). The DOC inlet failed to reach at least 572°F (300°C) and the DOC outlet did not get to 1022°F (550°C) during the regeneration attempt.
How serious is this fault code?
This is a serious issue that requires immediate attention. If you get SPN 3713, do not continue driving the vehicle. Park it safely and contact your dealer or a qualified mechanic right away. Continuing to operate with an aborted regeneration can lead to clogged DPF filters and more severe damage.
What are the common causes of SPN 3713?
Common causes include:
- Leaking or damaged charge air cooler (CAC) hoses
- Exhaust leaks before or around the DOC/DPF
- Faulty exhaust gas temperature sensors
- Low coolant level or coolant leaks
- Defective hydrocarbon (HC) doser
What parts are involved with this code?
The key components are:
- Diesel Oxidation Catalyst (DOC) – converts CO and hydrocarbons to CO2 and H2O
- Diesel Particulate Filter (DPF) – traps soot
- Exhaust Gas Temperature (EGT) Sensors – monitor DOC and DPF temperatures
What are the diagnostic steps for SPN 3713?
- Check for visible exhaust leaks, especially near the DOC/DPF. Repair leaks.
- Inspect charge air cooler hoses for damage. Replace as needed.
- Verify coolant level. Fix any coolant leaks.
- Using a scan tool, review EGT sensor live data. Replace faulty sensors.
- If no other issues found, remove and inspect HC doser. Clean or replace it.
What are the typical repair costs?
Repair costs depend on the root cause. Approximate parts costs:
- EGT sensors: $200-300 USD ($180-270 EUR) each
- HC doser: $800-1200 USD ($720-1080 EUR)
- CAC hoses: $150-300 USD ($135-270 EUR)
- Coolant: $25-50 USD ($23-45 EUR) per gallon (3.8 L)
Labor is typically 3-8 hours. Total repairs can range from a few hundred to several thousand dollars/euros.
How can I prevent this fault from occurring?
Perform regular maintenance, including:
- Checking coolant level
- Inspecting charge air cooler hoses
- Monitoring for exhaust leaks
What other fault codes are related to SPN 3713?
Some codes commonly seen with SPN 3713:
- SPN 3556 (AT1 Outlet Gas Temperature Sensor)
- SPN 3216 (AT1 Intake Gas Temperature Sensor)
- SPN 4094 (NOx limits exceeded – Insufficient Reagent Quality)
Is SPN 3713 specific to certain engine makes/models?
No, SPN 3713/FMI 31 is a standard J1939 code that can apply to many makes and models of diesel trucks and equipment. However, always consult the manufacturer's service information for model-specific troubleshooting details.
Can low DEF/AdBlue cause SPN 3713?
Not directly. SPN 3713 indicates an aborted regeneration due to low DOC temperatures. However, problems with the DEF system could potentially trigger other faults like SPN 4094 alongside SPN 3713.
Will deleting emissions equipment prevent SPN 3713?
Removing the DOC/DPF and EGT sensors will likely prevent this specific fault code, but is illegal in most jurisdictions. Tampering with emissions controls results in excessive pollution and often masks underlying issues rather than fixing them properly. Focus on diagnosing the root cause.
Can bad fuel cause SPN 3713?
Potentially, yes. Poor quality or contaminated diesel fuel can cause incomplete combustion, soot buildup, and lower exhaust temperatures. Always use ULSD fuel from reputable suppliers.
Is SPN 3713 covered under emissions warranty?
In most cases, yes. The DOC, DPF, EGT sensors, and HC doser are typically part of the emissions system and should be covered under the emissions warranty period, even if the base powertrain warranty has expired. Check with your dealer to confirm coverage.
How do I clear the SPN 3713 code?
In most cases, you should not clear this fault code until repairs are completed. Clearing it prematurely will erase valuable freeze frame data that can help pinpoint the issue. After repairs, the code should clear itself after several drive cycles. If not, use a scan tool to clear it.
Can low compression cause SPN 3713?
Yes, low compression in one or more cylinders can lead to incomplete combustion, lower post-turbo EGTs, and aborted regenerations. Perform a compression test if other causes are ruled out.
Will a bad EGR valve cause SPN 3713?
A stuck open EGR valve can cause low exhaust temperatures by diluting the exhaust stream with cooler intake air. However, a stuck closed EGR should not directly cause SPN 3713. Inspect the EGR valve and passages for soot buildup or sticking.
Can a bad thermostat trigger SPN 3713?
Yes, a stuck open thermostat can overcool the engine, leading to lower post-turbo exhaust temperatures and incomplete regenerations. Check that the thermostat reaches and maintains correct operating temperature.
Can a clogged air filter cause SPN 3713?
Yes, a severely restricted air filter reduces airflow to the engine. This leads to incomplete combustion, lower EGTs, and possibly aborted regenerations. Check and replace air filters at the specified service intervals, more often in dusty conditions.
What are the risks of driving with SPN 3713?
Continuing to drive with an active SPN 3713 fault can cause soot to build up in the DOC/DPF due to incomplete regenerations. Eventually, the DPF can become completely clogged, requiring removal and cleaning or replacement. In some cases, the extra soot can lead to a runaway regeneration and DPF damage. Pull over and troubleshoot as soon as possible.
How long does it take to diagnose SPN 3713?
Diagnosis time varies depending on the root cause and tools available. A skilled technician with a scan tool and service information can often pinpoint the issue within 1-2 hours. However, intermittent faults or multiple issues can take longer to fully address.
In summary, SPN 3713 indicates an aborted regeneration due to low exhaust temperatures in the diesel oxidation catalyst (DOC). This is often caused by charge air or exhaust leaks, low coolant, or faulty
sensors. Diagnosis requires a systematic approach to inspect the air, exhaust, and cooling systems. Repair costs depend on the specific issue found. Driving with an active SPN 3713 fault risks clogging the DPF, so the vehicle should be parked and serviced promptly. Proper preventive maintenance of the air, fuel, and cooling systems can help avoid this issue.
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