P20E8 on Jeep
Reductant Pressure Too Low
P20E8 on Jeep vehicles indicates reductant pressure too low. Au7o has documented this code across 1 Jeep model — most commonly on Grand Cherokee. P20E8 is a generic powertrain code that applies to diesel vehicles with a Selective Catalytic Reduction (SCR) emissions system, which injects diesel exhaust fluid (DEF, also sold as AdBlue) into the exhaust to convert smog-forming nitrogen oxides into harmless nitrogen and water. The engine control module sets this code when the DEF pump cannot build or hold the pressure the system needs (roughly 70-90 psi on most applications) to dose fluid accurately into the exhaust stream. Day to day you may notice little beyond a check engine light and a DEF or SCR warning message, though some vehicles show reduced power. Because SCR operation is emissions-mandated, ignoring the code typically starts a countdown to a derate: the vehicle will progressively limit speed (often to 55 mph, then as low as 5 mph on trucks) or refuse to restart until the fault is repaired. Some manufacturers word the same code as "DEF Pressure Too Low" or "SCR Urea Pressure Too Low," but the meaning is identical. Typical repair costs on Jeep range from $900 to $2,500, depending on the specific model and root cause.
Common Causes of P20E8
- •Failed or weak DEF (reductant) pump that cannot build specified pressure
- •Clogged reductant pump filter cartridge — DEF crystals gumming the internal filter is the most common cause on Duramax and Power Stroke trucks
- •Contaminated, diluted, or crystallized DEF fluid (or DEF frozen in cold weather due to a failed heater)
- •Leaking DEF supply lines or fittings, or a DEF injector stuck open and bleeding off pressure
- •Faulty reductant pressure sensor giving a false low reading
- •Damaged or corroded wiring/connectors to the DEF pump or pressure sensor
- •Low DEF tank level
P20E8 on Jeep by Model
Jeep Grand Cherokee(1 issue)
- 3.0L EcoDiesel DEF Tank/Heater/Pump Failure Triggering Limp Mode and No-Start Countdown2014-2016
The diesel-exhaust-fluid (DEF/reductant) system on the 3.0L EcoDiesel Grand Cherokee is a frequent failure point. The integrated DEF tank assembly bundles the pump, heater, and level/temperature/pressure sensors into one unit; when any single internal component fails (commonly the pump pressure or the tank heater), it sets emissions codes. Because Mopar does not sell the internal components separately, a single failure requires replacing the entire tank assembly. Critically, an unresolved DEF fault escalates to a speed-limited limp mode and ultimately a no-start once the dashboard mileage countdown expires, stranding the vehicle.
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What does P20E8 mean on Jeep?▼
P20E8 stands for "Reductant Pressure Too Low." P20E8 is a generic powertrain code that applies to diesel vehicles with a Selective Catalytic Reduction (SCR) emissions system, which injects diesel exhaust fluid (DEF, also sold as AdBlue) into the exhaust to convert smog-forming nitrogen oxides into harmless nitrogen and water. The engine control module sets this code when the DEF pump cannot build or hold the pressure the system needs (roughly 70-90 psi on most applications) to dose fluid accurately into the exhaust stream. Day to day you may notice little beyond a check engine light and a DEF or SCR warning message, though some vehicles show reduced power. Because SCR operation is emissions-mandated, ignoring the code typically starts a countdown to a derate: the vehicle will progressively limit speed (often to 55 mph, then as low as 5 mph on trucks) or refuse to restart until the fault is repaired. Some manufacturers word the same code as "DEF Pressure Too Low" or "SCR Urea Pressure Too Low," but the meaning is identical. On Jeep specifically, this code is documented across 1 model.
What causes P20E8 on Jeep vehicles?▼
Common causes on Jeep: Failed or weak DEF (reductant) pump that cannot build specified pressure, Clogged reductant pump filter cartridge — DEF crystals gumming the internal filter is the most common cause on Duramax and Power Stroke trucks, Contaminated, diluted, or crystallized DEF fluid (or DEF frozen in cold weather due to a failed heater), Leaking DEF supply lines or fittings, or a DEF injector stuck open and bleeding off pressure, Faulty reductant pressure sensor giving a false low reading. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P20E8 on a Jeep?▼
Repair costs on Jeep range from $900 to $2,500, depending on the specific model and root cause.
Which Jeep models have P20E8 documented?▼
Au7o has documented P20E8 on 1 Jeep model: Grand Cherokee.