Low diesel exhaust fluid level in the tank; Restricted or clogged reductant filter or pick-up screen; Weak or failing reductant pump; Leaking or disconnected reductant line or fitting; Faulty reductant pressure sensor; Crystallized or frozen reductant in the lines or pump; Open or shorted wiring to the reductant pump or pressure sensor

DTC codes / P20xx · Fuel and air metering and auxiliary emission controls / P20E0

P20E0Reductant Pressure Too Low

Q: What does code P20E0 mean?

Reductant Pressure Too Low. P20E0 indicates that the powertrain control module has detected a reductant pressure that is below the expected threshold for proper selective catalytic reduction operation. The computer monitors the reductant pressure sensor and commands the pump to maintain a specific pressure, and when the actual pressure falls short of the commanded value for a calibrated time, this code is stored.

P20E0 indicates that the powertrain control module has detected a reductant pressure that is below the expected threshold for proper selective catalytic reduction operation. The computer monitors the reductant pressure sensor and commands the pump to maintain a specific pressure, and when the actual pressure falls short of the commanded value for a calibrated time, this code is stored.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Reductant low-pressure warning message displayed on the dashboard
Reduced engine power or limp mode in some vehicles
Increased diesel exhaust fluid consumption due to the system trying to compensate
Rough running or hesitation if the system enters a derate strategy
A noticeable ammonia odor from the exhaust if reductant is over-injected

Common causes, most likely first

Low diesel exhaust fluid level in the tank
Restricted or clogged reductant filter or pick-up screen
Weak or failing reductant pump
Leaking or disconnected reductant line or fitting
Faulty reductant pressure sensor
Crystallized or frozen reductant in the lines or pump
Open or shorted wiring to the reductant pump or pressure sensor

How to diagnose and fix it

Verify diesel exhaust fluid level and top off with the correct specification fluid
Inspect the reductant tank, lines, and fittings for leaks or damage
Check the reductant filter and pick-up screen for contamination and replace if restricted
Command the reductant pump on with a scan tool and observe actual versus desired pressure
Test the reductant pressure sensor signal for rationality and compare with a known good sensor
Perform a reductant system bleed procedure to remove air from the lines
If pressure remains low, replace the reductant pump or pressure sensor as diagnosed

Before you replace the reductant pump

A low diesel exhaust fluid level is the most common cause of P20E0, so always check the tank level before condemning any component.
Crystallized urea can block the pick-up screen or filter, mimicking a failed pump, and a thorough cleaning often restores normal pressure.
The reductant pressure sensor can drift and report low pressure even when the pump is delivering correctly, so compare its reading with a mechanical gauge if possible.
Air trapped in the reductant lines after a refill or repair can cause low pressure codes until the system is properly bled with a scan tool.
This code does not always mean the pump is faulty; wiring issues or a poor ground can cause the same low-pressure condition.

Can I keep driving with P20E0?

You can usually continue driving to a service location, but avoid heavy loads or long trips because the vehicle may enter limp mode and further reduce power. Do not ignore the warning light, as continued driving with low reductant pressure can lead to more extensive system damage.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.