Reductant Pressure Sensor A Circuit Low
The reductant pressure sensor is reporting low pressure in the SCR system.
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What it means (plain English)
Inside the engine's computer, there's a sensor that measures how much pressure is in the fluid that helps reduce emissions. If this sensor reads too low, it triggers a warning.
What the computer is actually seeing
The engine control module (ECM) sees that the voltage signal from the reductant pressure sensor is lower than expected, indicating a potential fault in the system.
What a healthy reading looks like
The sensor should typically output a voltage between 0.5V to 4.5V when the system is working correctly. Values below 0.5V indicate a problem.
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. Check the DEF fluid level; it should be above the minimum mark.
- 22. Inspect the wiring and connectors at the reductant pressure sensor for damage or corrosion.
- 33. Measure the voltage output from the reductant pressure sensor with a multimeter; it should be within 0.5V to 4.5V.
- 44. If voltage is low, replace the reductant pressure sensor and retest.
- 55. If the wiring is damaged, repair or replace as necessary and retest. If the issue persists, check for blockage in the SCR system.
Common causes
- Faulty reductant pressure sensor
- Wiring issue or damaged connector for the sensor
- Low DEF (Diesel Exhaust Fluid) level
- Blockage in the SCR system
Typical repair cost
$$ - $$$
Related codes
Frequently asked questions
Is it safe to drive with P24A2 code?
It's drivable, but you may notice reduced performance and increased emissions; fix soon.
Will this code come back after clearing it?
If the underlying issue isn't resolved, yes, it will likely return.
Why is this code showing alongside codes like P20B9?
These codes are related as they all involve the SCR and reductant systems; a fault in one can trigger multiple codes.
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