The P2048: Reductant Injection Valve Circuit Low Bank 1 Unit 1 code indicates that the voltage in the circuit controlling the reductant injection valve for Bank 1, Unit 1 is lower than expected. This could be caused by a faulty valve, low voltage in the circuit, or issues with wiring and connectors.
P2048 – Quick Overview
Code | Information |
---|---|
Meaning | P2048: Reductant Injection Valve Circuit Low Bank 1 Unit 1 |
Is it serious? | Yes, low voltage in the circuit can prevent proper DEF injection, leading to poor NOx reduction and increased emissions. |
Possible causes | – Low voltage in the valve circuit – Faulty valve or wiring – Connector issues |
How to diagnose? | – Measure voltage in the valve circuit – Test the valve – Check wiring and connectors |
P2048 Meaning
The P2048: Reductant Injection Valve Circuit Low Bank 1 Unit 1 code indicates that the reductant (DEF) injection valve for Bank 1, Unit 1 is receiving lower voltage than expected. The valve controls the flow of DEF into the exhaust system to reduce NOx emissions. Low voltage in the circuit can result in improper DEF injection, causing the system to fail to control emissions effectively.
Step-by-step diagnostic guide
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to check for additional related codes that may provide more information on the health of the DEF system or valve circuit. | OBD-II Scanner |
Measure Voltage in the Valve Circuit | Use a multimeter to measure the voltage in the reductant injection valve circuit for Bank 1, Unit 1. Compare the voltage readings to the manufacturer’s specifications to confirm if it is too low. | Multimeter |
Test the Reductant Injection Valve | Use a diagnostic tool or multimeter to test the operation of the reductant injection valve. Check for proper voltage input and output, ensuring the valve operates as intended. | Multimeter, Diagnostic Tool |
Inspect Wiring and Connectors | Visually inspect all wiring and connectors leading to the reductant injection valve. Look for signs of damage, corrosion, or loose connections that could cause low voltage in the circuit. | Flashlight, Multimeter |
Perform Circuit Continuity Test | Perform a continuity test on the valve’s circuit wiring to ensure there are no shorts, breaks, or high resistance that could lead to low voltage issues. | Multimeter |
Check for Grounding Issues | Ensure that the reductant injection valve circuit is properly grounded. A poor ground connection can cause voltage drops, leading to improper valve operation. | Multimeter, Flashlight |
Replace the Reductant Injection Valve | If the valve is faulty and not performing as required, replace it with a new one. Ensure that the new valve is installed correctly with proper wiring connections. | Replacement Valve, Wrench |
Repair or Replace Damaged Wiring | Repair or replace any damaged wiring or connectors that are causing low voltage in the circuit to restore proper function to the valve. | Wiring Repair Kit |
Clear the Code and Test Drive | After completing repairs, clear the P2048 code using an OBD-II scanner. Take the vehicle for a test drive to confirm that the valve operates properly and the code does not return. | OBD-II Scanner, Vehicle Owner’s Manual |
Recheck for Codes | After the test drive, re-scan the vehicle to verify that the P2048 code has been cleared and the system is functioning correctly. | OBD-II Scanner |

OBD-II scanner Buyer’s Guide
- Scanner features explained
- Different types of scanners
- Scanners for coding/odometer/ECU/checks
- Best picks + discount codes

Hi, I am Juraj “Yuri” Lukacko. I got frustrated by unhelpful and scammy mechanics, so I decided to learn everything about car diagnostics myself. I test dozens of new car diagnostic tools every month along with learning new strategies to fix and customize cars. About Juraj Lukacko (Yuri)