P203F on Cadillac
Reductant Level Too Low
P203F on Cadillac vehicles indicates reductant level too low. Au7o has documented this code across 1 Cadillac model — most commonly on XT4. Set when the PCM determines the reductant (DEF/AdBlue) level in the tank is too low for the SCR system to properly reduce NOx. This is typically a genuine low-DEF condition requiring a refill, though a stuck-low level sensor can also trigger it. On modern diesels, ignoring it leads to escalating speed derate and eventual no-restart inducement. Typical repair costs on Cadillac range from $600 to $1,500, depending on the specific model and root cause.
Common Causes of P203F
- •Genuinely low DEF/AdBlue level (needs refill)
- •Faulty reductant level sensor reading low
- •DEF leak from the tank/lines
- •Contaminated or crystallized DEF affecting sensing
- •PCM/dosing control module fault
P203F on Cadillac by Model
Cadillac XT4(1 issue)
- Fuel Pump Control Module Failure Causes Sudden Stall and Crank-No-Start (P203F)2021-2025
The fuel pump power control module (FPCM), mounted under the vehicle near the fuel tank on 9-speed 2.0T LSY XT4s, fails internally and stops commanding the in-tank pump. The failure is typically abrupt with no preceding driveability symptoms: the engine cuts out at speed or refuses to restart after a normal shutdown, and the vehicle cranks but will not fire. Owners report repeat failures on the same vehicle. GM opened a fuel pump control module recall (campaign N252516900) covering a subset of build ranges, but NHTSA complaints show owners with out-of-scope VINs experiencing identical failures, and the pattern spans 2021 through 2025 build years.
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View P203F across all makes →Frequently Asked Questions
What does P203F mean on Cadillac?▼
P203F stands for "Reductant Level Too Low." Set when the PCM determines the reductant (DEF/AdBlue) level in the tank is too low for the SCR system to properly reduce NOx. This is typically a genuine low-DEF condition requiring a refill, though a stuck-low level sensor can also trigger it. On modern diesels, ignoring it leads to escalating speed derate and eventual no-restart inducement. On Cadillac specifically, this code is documented across 1 model.
What causes P203F on Cadillac vehicles?▼
Common causes on Cadillac: Genuinely low DEF/AdBlue level (needs refill), Faulty reductant level sensor reading low, DEF leak from the tank/lines, Contaminated or crystallized DEF affecting sensing, PCM/dosing control module fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P203F on a Cadillac?▼
Repair costs on Cadillac range from $600 to $1,500, depending on the specific model and root cause.
Which Cadillac models have P203F documented?▼
Au7o has documented P203F on 1 Cadillac model: XT4.