P2044 – Reductant Tank Temperature Sensor Circuit High

What is P2044?

P2044 is an OBD-II generic powertrain diagnostic trouble code that indicates the powertrain control module (PCM) has detected insufficient voltage in the reductant temperature sensor circuit. The reductant temperature sensor measures the temperature of the diesel exhaust fluid (DEF) in the selective catalytic reduction (SCR) system used to reduce NOx emissions in diesel vehicles.

Urgency and Drivability

A stored P2044 code should be considered severe and addressed as quickly as possible. Driving with this code active is not recommended as it could disable the SCR system and potentially cause catalyst damage if the underlying issue is not resolved promptly. While the vehicle may still be drivable in the short term, it's best to diagnose and repair the problem immediately to avoid more serious damage.

Applicability

P2044 is a generic powertrain code that applies to many OBD-II vehicles (1996 and newer), including Mercedes, Sprinter, Ford, GMC, Chevrolet and others. The specific repair steps may vary depending on the year, make, model and powertrain configuration.

Parts Involved

The main components related to code P2044 are:

• Reductant temperature sensor – measures DEF temperature, usually located in the DEF tank
• DEF tank – stores the diesel exhaust fluid
• SCR system – injects DEF into the exhaust to convert NOx into nitrogen and water
• Wiring and connectors between the sensor and PCM

Common Causes

Possible causes for P2044 include:

• Defective reductant temperature sensor
• Wiring issues such as damaged wires, loose connections, or corrosion
• Low DEF fluid level
• Contaminated or incorrect DEF fluid
• Faulty PCM (rare)

Diagnosis

To diagnose P2044:

1. Retrieve all stored codes and freeze frame data with a scan tool.
2. Visually inspect wiring and connectors for damage. Repair as needed.
3. Check DEF level and quality. Refill or replace fluid if low or contaminated.
4. Test the reductant temperature sensor with a digital multimeter and compare to specs. Replace if faulty.
5. If the sensor tests okay, check the wiring between the sensor and PCM for continuity, shorts, and proper voltage/ground signals. Repair wiring issues.
6. If the wiring checks out, the PCM may be faulty, but this is rare. Consult service information for further PCM diagnosis.

Repair Costs

The cost to diagnose and repair code P2044 can range from $100-500 (€85-425) or more depending on the root cause:

• Reductant temperature sensor: $75-200 (€65-170)
• DEF fluid: $10-30 (€8-25) per gallon/3.8 liters
• Wiring repairs: $50-300 (€40-255)
• PCM replacement: $500-1500 (€425-1275)

Labor costs are additional and vary by vehicle, shop rates, and location.

Prevention

To help prevent P2044, regularly maintain the emissions system by:

• Keeping the DEF tank filled with the proper fluid
• Addressing any fluid leaks promptly
• Keeping electrical connections clean and secure
• Repairing wiring and replacing faulty sensors as needed

Related Codes

Other codes that may appear along with P2044 include:

• P203F – Reductant Tank Temperature Sensor Circuit Range/Performance
• P204C – Reductant System Performance
• P20B9 – Reductant Injection Valve Control Circuit/Open

Consult service information and perform a thorough diagnosis, as multiple codes can have a common root cause or be interrelated.

Frequently Asked Questions About P2044

What does the OBD-II code P2044 mean?

P2044 is a generic powertrain diagnostic trouble code that indicates the powertrain control module (PCM) has detected insufficient voltage in the reductant temperature sensor circuit. The reductant temperature sensor measures the temperature of the diesel exhaust fluid (DEF) in the selective catalytic reduction (SCR) system used to reduce NOx emissions in diesel vehicles.

How severe is a P2044 code?

A P2044 code should be considered severe and addressed promptly. Driving with this code active is not recommended as it could disable the SCR system and potentially cause catalyst damage if the underlying issue is not resolved quickly. While the vehicle may still be drivable short-term, it's best to diagnose and repair the problem immediately to avoid more serious damage.

What are the common symptoms of a P2044 code?

Common symptoms may include:

• Illuminated check engine light
• Reduced fuel efficiency
• Excessive black smoke from exhaust
• Diminished engine performance
• Other SCR-related codes

What vehicles can get a P2044 code?

P2044 is a generic code that can occur in many OBD-II compliant vehicles (1996 and newer) equipped with a diesel engine and SCR system. This includes various models from Mercedes, Sprinter, Ford, GMC, Chevrolet and others. The specific repair steps may vary by year, make, model and powertrain configuration.

What are the possible causes of a P2044 code?

Possible causes include:

• Defective reductant temperature sensor
• Wiring issues like damaged wires, loose connections, or corrosion
• Low DEF fluid level
• Contaminated or incorrect DEF fluid
• Faulty PCM (rare)

How do you diagnose a P2044 code?

To properly diagnose a P2044 code:

1. Scan for all codes and document freeze frame data.
2. Visually inspect wiring and connectors. Repair as needed.
3. Check DEF level and quality. Refill or replace if low/contaminated.
4. Test the reductant temp sensor and compare to specs. Replace if faulty.
5. If the sensor is okay, check wiring between sensor and PCM for issues.
6. If wiring is okay, PCM may be faulty but this is uncommon.

Always consult vehicle-specific service information for detailed diagnostic procedures.

Can low DEF fluid cause a P2044?

Yes, a low DEF fluid level can potentially trigger a P2044 code. The reductant temperature sensor needs to be submerged in fluid to function properly. If the DEF level is too low, it may cause an implausible signal and set the code. Always check the DEF level when diagnosing P2044.

Can you drive with a P2044 code?

While it may be possible to drive short distances with a P2044 code, it is not recommended. This code indicates a problem with the SCR system which is critical for reducing harmful emissions. Driving with the code active could cause further damage to emissions components. The underlying issue should be diagnosed and repaired as soon as possible.

How much does it cost to fix a P2044 code?

The cost to repair a P2044 code can vary widely depending on the root cause:

• Reductant temperature sensor: $75-200
• DEF fluid: $10-30 per gallon
• Wiring repairs: $50-300
• PCM replacement: $500-1500

Labor costs are additional and will vary based on vehicle, shop rates, and location. Total repair costs could range from under $100 for a simple DEF refill to over $1000 if the PCM needs replaced.

Can a P2044 code clear itself?

It's possible for a P2044 code to clear itself if the underlying condition was intermittent and has been resolved. However, the code will likely reoccur if the root problem is not diagnosed and repaired. If the code clears and does not return after several drive cycles, it was likely an intermittent issue. If it keeps coming back, further diagnosis is needed.

What is the reductant temperature sensor?

The reductant temperature sensor measures the temperature of the diesel exhaust fluid (DEF) in the tank. This information is used by the PCM to control the SCR system and ensure the DEF dosing is correct for optimal NOx reduction. The sensor is typically located in the DEF tank and submerged in the fluid.

What other codes can occur with P2044?

Other codes that may appear along with P2044 include:

• P203F – Reductant Tank Temperature Sensor Circuit Range/Performance
• P204C – Reductant System Performance
• P20B9 – Reductant Injection Valve Control Circuit/Open

Always address all codes together, as multiple codes can have a common root cause or be interrelated. Clearing codes without fixing the underlying problems will likely cause them to return.

How often should the DEF fluid be checked?

DEF fluid level should be checked at every oil change interval or around every 5,000-10,000 miles. Low DEF fluid is a common cause of SCR system issues. Keeping the fluid topped off can help prevent problems like a P2044 code. Consult your owner's manual for the specific maintenance schedule for your vehicle.

What is the normal operating temperature range for DEF?

The normal operating temperature range for most DEF fluids is between 12°F and 86°F (-11°C to 30°C). Temperatures outside this range can affect the fluid quality and dosing accuracy. The reductant temperature sensor monitors the DEF temperature to ensure it stays within the optimal range for peak SCR efficiency.

Can extreme temperatures cause a P2044 code?

Extreme cold or hot temperatures can potentially cause issues with the DEF system that could trigger a P2044 code. DEF fluid can freeze at temperatures below 12°F (-11°C) which may cause erratic reductant temperature sensor readings. In extreme heat above 86°F (30°C), the fluid can degrade faster which may also affect sensor performance.

Can a bad reductant temp sensor affect engine performance?

A failing reductant temperature sensor can cause incorrect DEF dosing which may affect SCR performance and engine efficiency. If the SCR system is not working optimally to reduce NOx, the engine may go into a limp-home mode to prevent catalyst damage. This can result in reduced power, acceleration, and fuel economy until the problem is resolved.

What does the DEF warning light mean?

The DEF warning light indicates that the diesel exhaust fluid level is low or there is a problem with the SCR system. If the light is on, check the DEF level and quality first. If the fluid is okay, scan for codes to pinpoint other potential SCR issues. A P2044 code will usually trigger the DEF light. Resolve the code to turn the light off.

Can a P2044 code affect emissions testing?

Yes, a stored P2044 code will likely cause your vehicle to fail an OBD-II emissions test. The code indicates a problem with the SCR system which is a critical emissions control device. You will need to repair the underlying issue and clear the code before retesting. An active or pending P2044 code will prevent the readiness monitors from completing.

How do you replace a reductant temperature sensor?

The general steps to replace a reductant temperature sensor are:

1. Locate the DEF tank and disconnect the negative battery cable.
2. Drain the DEF fluid from the tank.
3. Remove the DEF delivery module from the tank to access the sensor.
4. Disconnect the electrical connector and remove the old sensor.
5. Install the new sensor and reconnect the electrical connector.
6. Reinstall the delivery module and refill the tank with new DEF fluid.
7. Clear codes and verify repair.

Always refer to vehicle-specific service information for detailed replacement instructions, as the exact procedure can vary by application.

How do you prevent a P2044 code from reoccurring?

To help prevent a P2044 code from coming back:

• Regularly check and refill the DEF tank with the proper fluid
• Fix any DEF leaks immediately to prevent low fluid levels
• Keep electrical connections clean and secure to avoid wiring issues
• Replace faulty sensors and wiring promptly if issues arise
• Use OEM or high-quality aftermarket parts for best reliability

Following the manufacturer's recommended maintenance schedule for the SCR system can also help prevent recurring problems with P2044 or other emissions-related codes. Consult your owner's manual for service intervals.