P2042 Code - Reductant Temperature Sensor Circuit
Quick Answer
The P2042 diagnostic trouble code (DTC) refers to a malfunction in the reductant temperature sensor circuit. Common causes include Faulty Temperature Sensor: The most common cause of the P2042 code is a defective reductant temperature sensor itself, Wiring Issues: Corroded, damaged, or loose wiring connections in the sensor circuit can also trigger this code, ECM Malfunction: A malfunctioning engine control module can disrupt communication with the reductant temperature sensor. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P2042 indicates Reductant Temperature Sensor Circuit.
- Common causes
- Common causes include Faulty Temperature Sensor: The most common cause of the P2042 code is a defective reductant temperature sensor itself, Wiring Issues: Corroded, damaged, or loose wiring connections in the sensor circuit can also trigger this code, ECM Malfunction: A malfunctioning engine control module can disrupt communication with the reductant temperature sensor.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code P2042 Description
The P2042 diagnostic trouble code (DTC) refers to a malfunction in the reductant temperature sensor circuit. This sensor is a crucial component of the selective catalytic reduction (SCR) system in modern diesel vehicles. The reductant temperature sensor is responsible for measuring the temperature of the diesel exhaust fluid (DEF) before it enters the SCR system. The SCR system uses DEF to reduce harmful nitrogen oxide emissions into harmless nitrogen and water vapor.
Common Causes of P2042
- Faulty Temperature Sensor: The most common cause of the P2042 code is a defective reductant temperature sensor itself.
- Wiring Issues: Corroded, damaged, or loose wiring connections in the sensor circuit can also trigger this code.
- ECM Malfunction: A malfunctioning engine control module can disrupt communication with the reductant temperature sensor.
- DEF Contamination: Contaminated DEF can cause sensor inaccuracies and trigger the P2042 code.
- Environmental Factors: Extreme temperatures or exposure to moisture can also affect the sensor's performance.
Symptoms of P2042
- Check Engine Light: The most common symptom associated with the P2042 code is the illumination of the check engine light on the vehicle's dashboard.
- Reduced Engine Performance: A malfunctioning reductant temperature sensor can cause the vehicle to experience reduced engine performance, such as decreased power or acceleration.
- Poor Fuel Economy: Inaccurate DEF dosing due to a faulty reductant temperature sensor can lead to poor fuel economy.
- Failed Emissions Test: If the issue is not resolved, the vehicle may fail emissions tests due to increased nitrogen oxide emissions.
How to Fix P2042
- Diagnose the Issue: Use a diagnostic scanner to retrieve the specific DTC and pinpoint the exact cause of the problem.
- Inspect Wiring: Check the wiring harness and connectors for any signs of damage, corrosion, or loose connections. Repair or replace as necessary.
- Test the Sensor: Test the reductant temperature sensor using a multimeter to verify its functionality. Replace the sensor if it fails the test.
- Clear DTCs: After repairing the issue, clear the DTCs from the ECM memory and retest the vehicle to ensure the problem has been resolved.
- Perform DEF System Reset: Some vehicles may require a DEF system reset procedure to recalibrate the reductant temperature sensor and ensure proper operation.
Cost to Fix P2042
The cost of repairing a reductant temperature sensor circuit issue can vary depending on the specific cause of the problem and the vehicle's make and model. On average, the parts cost for a new reductant temperature sensor ranges from $50 to $150, while labor costs can range from $100 to $200. Therefore, the total repair cost can be estimated to be between $150 and $350. It's essential to consider additional diagnostic fees and potential expenses if other components require replacement or repair. As labor rates can vary, it's recommended to check with local auto repair shops for more accurate pricing.
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Code P2042 Information for Specific Makes
- P2042 BMW — Reductant Temperature Sensor Circuit
- P2042 Dodge — Reductant Temperature Sensor Circuit
- P2042 Ford — Reductant Temperature Sensor Circuit
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