Reductant Pressure Too Low
The system has detected low pressure in the DEF tank or line.
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)
It's like the gas tank for the cleaning fluid (urea) is either empty or the pump isn’t working properly, so the engine can't clean up exhaust fumes as it should.
What the computer is actually seeing
The control module monitors the pressure in the DEF supply line, expecting it to be above a certain threshold, typically around 3 to 10 psi during operation. If the pressure drops below this threshold, it triggers a fault code.
What a healthy reading looks like
Expected DEF line pressure should be between 5 and 10 psi while the engine is running.
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.
- 1Check DEF fluid level in the tank; top off if low; if filled, proceed to next step.
- 2Inspect DEF lines for any kinks, blockages, or leaks; repair if found; if none, move on.
- 3Test the DEF pressure sensor with a multimeter; expected output is around 0.5V to 2.5V at idle; replace if faulty.
- 4Check the operation of the DEF injector pump; ensure it is running and providing adequate pressure; replace if defective.
Common causes
- Low DEF fluid level in the tank.
- Obstructed DEF lines or filter.
- Faulty DEF pressure sensor.
- Failed DEF injector pump.
Typical repair cost
$$$
Related codes
Frequently asked questions
Can I drive the vehicle with this code?
Yes, but you should fix it soon to avoid emissions issues and potential limp mode.
Will it come back if I reset the code?
If the underlying issue isn't fixed, the code will likely return.
Why does this code pair with low DEF level?
Low DEF will cause the system to register low pressure as the pump struggles to draw fluid.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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