Reductant Pressure Sensor Range/Performance Problem
This code indicates an issue with the reductant pressure sensor’s performance or range.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
Inside the vehicle’s engine control module (ECM), the reductant pressure sensor monitors the pressure of the diesel exhaust fluid (DEF) in the tank. If the pressure reading is too high or too low, it triggers a fault code. The sensor voltage should ideally be between 0.5V (low pressure) and 4.5V (high pressure).
What the computer is actually seeing
The ECM expects a voltage signal from the reductant pressure sensor that correlates with a specific pressure level in the DEF tank. If the voltage falls outside the range of 0.5V to 4.5V under normal conditions, the code P2043 is triggered.
What a healthy reading looks like
Reductant pressure voltage should normally be between 0.5V and 4.5V corresponding to DEF pressure from 0 to 100 psi (pounds per square inch).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the vehicle's DEF level; ensure it's above the minimum specified by the manufacturer.
- 22. Check the wiring and connectors for the reductant pressure sensor for corrosion, damage, or loose connections. Repair as needed.
- 33. Measure the voltage at the reductant pressure sensor. It should be between 0.5V and 4.5V; if not, replace the sensor.
- 44. If voltage is within range, check the DEF for contamination or quality; replace if needed.
- 55. Clear the code and perform a test drive to see if the code returns.
Common causes
- Defective reductant pressure sensor
- Faulty wiring or connector to sensor
- Low or contaminated diesel exhaust fluid (DEF)
- Clogged DEF injector or lines
- ECM software issues
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code active?
Yes, but performance can be degraded and emissions may be affected. You should fix it soon.
Will the code come back after I clear it?
If the underlying issue isn't resolved, it will likely return.
Why does this code sometimes pair with P2040?
Both codes deal with issues in the reductant system, often pointing to sensor faults or pressure-related problems.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →