Skip to content

P203F · Manufacturer communications

A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.

P203F ← What does this code mean?

27 Results

18-067-26 ↗

RAM · 2026-07-09

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0088-00 - Fuel Rail Pressure Too High - Bank 1. ● P208B-00 - Reductant Pump 1 Control Performance. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P0506-00 - Idle Control System RPM - Lower Than Expected. ● P20CF-00 - Exhaust Aftertreatment Fuel Injector "A" Stuck Open. ● P20DB-00 - Exhaust Aftertreatment Fuel Supply Control Stuck Open. ● P040B-00 - EGR Temperature Sensor 1 Circuit Performance. ● U0109-00 - Lost Communication With Fuel Pump Control Module. ● P1451-00 - Diesel Particulate Filter System Performance. ● P2463-00 - Diesel…

18-025-26 REV. B ↗

RAM · 2026-07-09

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0088-00 - Fuel Rail Pressure Too High - Bank 1. ● P208B-00 - Reductant Pump 1 Control Performance. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P0506-00 - Idle Control System RPM - Lower Than Expected. ● P20CF-00 - Exhaust Aftertreatment Fuel Injector "A" Stuck Open. ● P20DB-00 - Exhaust Aftertreatment Fuel Supply Control Stuck Open. ● P040B-00 - EGR Temperature Sensor 1 Circuit Performance. ● U0109-00 - Lost Communication With Fuel Pump Control Module. ● P1451-00 - Diesel Particulate Filter System Performance. ● P2463-00 - Diesel…

18-025-26 REV. A ↗

RAM · 2026-05-19

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0088-00 - Fuel Rail Pressure Too High - Bank 1. ● P208B-00 - Reductant Pump 1 Control Performance.** ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P0506-00 - Idle Control System RPM - Lower Than Expected. ● P20CF-00 - Exhaust Aftertreatment Fuel Injector "A" Stuck Open. ● P20DB-00 - Exhaust Aftertreatment Fuel Supply Control Stuck Open. ● P040B-00 - EGR Temperature Sensor 1 Circuit Performance. ● U0109-00 - Lost Communication With Fuel Pump Control Module. ● P1451-00 - Diesel Particulate Filter System Performance. ● P2463-00 - Diesel…

18-014-26 REV. A ↗

RAM · 2026-04-22

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0088-00 - Fuel Rail Pressure Too High - Bank 1.** ● P20CF-00 - Exhaust After treatment Fuel Injector "A" Stuck Open. ● P20DB-00 - Exhaust After treatment Fuel Supply Control Stuck Open. ● U0109-00 - Lost Communication With Fuel Pump Control Module. ● P1451-00 - Diesel Particulate Filter System Performance. ● P2463-00 - Diesel Particulate Filter Restriction - Soot Accumulation Bank 1. ● P2459-00 - Diesel Particulate Filter Regeneration Too Frequent. ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/performance. ● P2543-00 -…

S2525000002 REV.B ↗

RAM · 2026-03-31

Diesel Exhaust Fluid (DEF) Gauge Fluctuates Or Is Erratic. Diagnostic Trouble Code (DTC) P203F – Reductant Level Too Low.

18-025-26 ↗

RAM · 2026-02-19

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P0506-00 - Idle Control System RPM - Lower Than Expected. ● P20CF-00 - Exhaust Aftertreatment Fuel Injector "A" Stuck Open. ● P20DB-00 - Exhaust Aftertreatment Fuel Supply Control Stuck Open. ● P040B-00 - EGR Temperature Sensor 1 Circuit Performance. ● U0109-00 - Lost Communication With Fuel Pump Control Module. ● P1451-00 - Diesel Particulate Filter System Performance. ● P2463-00 - Diesel Particulate Filter Restriction - Soot Accumulation Bank 1. ● P1191-00-Inlet Air Temperature Sensor…

S2525000002 REV.A ↗

RAM · 2026-02-09

Diesel Exhaust Fluid (DEF) Gauge Fluctuates Or Is Erratic. Diagnostic Trouble Code (DTC) P203F – Reductant Level Too Low.

18-012-26 REV.A ↗

RAM · 2026-02-05

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0072-00 - Ambient Air Temperature Sensor Circuit "A" Low. ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P2543-00 - Low Pressure Fuel System Sensor Circuit Intermittent. ● P20EE-00 - SCR Nox Catalyst Efficiency Below Threshold - Bank 1 Catalyst 1. ● P203F-00 - Reductant Level Too Low. ● P2698-00 - Exhaust Aftertreatment Fuel Injector "A" Performance. ● P06B9-00 - Cylinder 1 Glow Plug Circuit Performance. ● P06BA-00 - Cylinder 2 Glow Plug Circuit Performance. ● P06BB-00 - Cylinder 3 Glow Plug…

18-014-26 ↗

RAM · 2026-02-03

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P20CF - 00 Exhaust After treatment Fuel Injector "A" Stuck Open. ● P20DB - 00 Exhaust After treatment Fuel Supply Control Stuck Open. ● U0109 - 00 Lost Communication With Fuel Pump Control Module. ● P1451 - 00 Diesel Particulate Filter System Performance. ● P2463 - 00 Diesel Particulate Filter Restriction - Soot Accumulation Bank 1. ● P2459 - 00 Diesel Particulate Filter Regeneration Too Frequent.** ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/performance. ● P2543-00 - Low Pressure Fuel System Sensor Circuit…

18-013-26 ↗

RAM · 2026-02-02

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must SYMPTOM: exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P20CF - 00 Exhaust After treatment Fuel Injector "A" Stuck Open. ● P20DB - 00 Exhaust After treatment Fuel Supply Control Stuck Open. ● U0109 - 00 Lost Communication With Fuel Pump Control Module. ● P1451 - 00 Diesel Particulate Filter System Performance. ● P2463 - 00 Diesel Particulate Filter Restriction - Soot Accumulation Bank 1. ● P2459 - 00 Diesel Particulate Filter Regeneration Too Frequent.** ● P0263 - 00 Cylinder 1 Contribution/balance. ● P0266 - 00 Cylinder 2 Contribution-balance. ● P0269 - 00 Cylinder 3 Contribution/balance. ● P0272 - 00 Cylinder 4…

18-012-26 ↗

RAM · 2026-01-31

NOte: Revision is being created to correct the Models affected. Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0072-00 - Ambient Air Temperature Sensor Circuit "A" Low. ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P2543-00 - Low Pressure Fuel System Sensor Circuit Intermittent. ● P20EE-00 - SCR Nox Catalyst Efficiency Below Threshold - Bank 1 Catalyst 1. ● P203F-00 - Reductant Level Too Low. ● P2698-00 - Exhaust Aftertreatment Fuel Injector "A" Performance. ● P06B9-00 - Cylinder 1 Glow Plug Circuit Performance. ● P06BA-00 - Cylinder 2 Glow Plug…

18-011-26 ↗

RAM · 2026-01-31

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0072-00 - Ambient Air Temperature Sensor Circuit "A" Low. ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P2543-00 - Low Pressure Fuel System Sensor Circuit Intermittent. ● P20EE-00 - SCR Nox Catalyst Efficiency Below Threshold - Bank 1 Catalyst 1. ● P203F-00 - Reductant Level Too Low. ● P2698-00 - Exhaust Aftertreatment Fuel Injector "A" Performance. ● P06B9-00 - Cylinder 1 Glow Plug Circuit Performance. ● P06BA-00 - Cylinder 2 Glow Plug Circuit Performance. ● P06BB-00 - Cylinder 3 Glow Plug Circuit…

18-010-26 ↗

RAM · 2026-01-31

Flash: Powertrain Control Module (PCM) Updates V2C Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P06B9-00 - Cylinder 1 Glow Plug Circuit Performance. ● P06BA-00 - Cylinder 2 Glow Plug Circuit Performance. ● P06BB-00 - Cylinder 3 Glow Plug Circuit Performance. ● P06BC-00 - Cylinder 4 Glow Plug Circuit Performance. ● P06BD-00 - Cylinder 5 Glow Plug Circuit Performance. ● P06BE-00 - Cylinder 6 Glow Plug Circuit Performance. ● P0263-00 - Cylinder 1 Contribution/balance. ● P0266-00 - Cylinder 2 Contribution-balance. ● P0269-00 - Cylinder 3 Contribution/balance. ● P0272-00 - Cylinder 4 Contribution/balance. ● P0275-00 - Cylinder 5 Contribution/balance. ● P0278-00 -…

18-009-26 ↗

RAM · 2026-01-31

Flash: Powertrain Control Module (PCM) Updates V2C Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P06B9-00 - Cylinder 1 Glow Plug Circuit Performance. ● P06BA-00 - Cylinder 2 Glow Plug Circuit Performance. ● P06BB-00 - Cylinder 3 Glow Plug Circuit Performance. ● P06BC-00 - Cylinder 4 Glow Plug Circuit Performance. ● P06BD-00 - Cylinder 5 Glow Plug Circuit Performance. ● P06BE-00 - Cylinder 6 Glow Plug Circuit Performance. ● P0263-00 - Cylinder 1 Contribution/balance. ● P0266-00 - Cylinder 2 Contribution-balance. ● P0269-00 - Cylinder 3 Contribution/balance. ● P0272-00 - Cylinder 4 Contribution/balance. ● P0275-00 - Cylinder 5 Contribution/balance. ● P0278-00 -…

18-102-25 ↗

RAM · 2025-11-18

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P2543-00 - Low Pressure Fuel System Sensor Circuit Intermittent. ● P214D-00 - SCR NOx Catalyst Outlet Temperature Too High During Particulate Filter Regeneration. ● P242B-00 - Exhaust Gas Temperature Sensor Circuit Performance - Bank 1 Sensor 3. ● P24DA - Particulate Matter Sensor Exhaust Sample Error Bank 1. ● P20EE-00 - SCR NOx Catalyst Efficiency Below Threshold - Bank 1 Catalyst 1. ● P226C-00 - Turbocharger Boost Control "A" Slow Response. ● P2281-00 - Air…

18-101-25 ↗

RAM · 2025-11-18

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/Performance. ● P2543-00 - Low Pressure Fuel System Sensor Circuit Intermittent. ● P214D-00 - SCR NOx Catalyst Outlet Temperature Too High During Particulate Filter Regeneration. ● P242B-00 - Exhaust Gas Temperature Sensor Circuit Performance - Bank 1 Sensor 3. ● P24DA - Particulate Matter Sensor Exhaust Sample Error Bank 1. ● P20EE-00 - SCR NOx Catalyst Efficiency Below Threshold - Bank 1 Catalyst 1. ● P226C-00 - Turbocharger Boost Control "A" Slow Response. ● P2281-00 - Air…

18-021-25 REV. B ↗

RAM · 2025-10-08

Flash: Powertrain Control Module (PCM) Updates *Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● P0087-00 - Fuel Rail Pressure Too Low. ● P2540-00 - Low Pressure Fuel System Sensor Circuit Range/performance. ● P2543-00 - Low Pressure Fuel System Sensor Circuit Intermittent. ● P214D-00 - SCR NOX Catalyst Outlet Temperature Too High During Particulate Filter Regeneration. ● P242B-00 - Exhaust Gas Temperature Sensor Circuit Performance - Bank 1 Sensor 3. ● P24DA-00 - Particulate Matter Sensor Exhaust Sample Error Bank 1. ● P20EE-00 - SCR Nox Catalyst Efficiency Below Threshold - Bank 1 Catalyst 1. ● P226C-00 - Turbocharger Boost Control "A" Slow Response. ● P2281-00 - Air…

18-075-25 REV. A ↗

RAM · 2025-10-02

Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle may exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs): ● **P0263 - 00 Cylinder 1 Contribution/balance. ● P0266 - 00 Cylinder 2 Contribution-balance. ● P0269 - 00 Cylinder 3 Contribution/balance. ● P0272 - 00 Cylinder 4 Contribution/balance. ● P0275 - 00 Cylinder 5 Contribution/balance. ● P0278 - 00 Cylinder 6 Contribution/balance. ● P026B - 00 Injection Timing Performance. ● P020A - 00 Cylinder 1 Injection Timing. ● P020B - 00 Cylinder 2 Injection Timing. ● P020C - 00 Cylinder 3 Injection Timing. ● P020D - 00 Cylinder 4 Injection Timing. ● P020E - 00 Cylinder 5 Injection Timing. ● P020F - 00 Cylinder 6 Injection Timing. ● P06B9 -…

18-074-25 REV. A ↗

RAM · 2025-10-02

Flash: Powertrain Control Module (PCM) Updates *Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs):** ● **P0263 - 00 Cylinder 1 Contribution/balance. ● P0266 - 00 Cylinder 2 Contribution-balance. ● P0269 - 00 Cylinder 3 Contribution/balance. ● P0272 - 00 Cylinder 4 Contribution/balance. ● P0275 - 00 Cylinder 5 Contribution/balance. ● P0278 - 00 Cylinder 6 Contribution/balance. ● P026B - 00 Injection Timing Performance. ● P020A - 00 Cylinder 1 Injection Timing. ● P020B - 00 Cylinder 2 Injection Timing. ● P020C - 00 Cylinder 3 Injection Timing. ● P020D - 00 Cylinder 4 Injection Timing. ● P020E - 00 Cylinder 5 Injection Timing. ● P020F - 00 Cylinder 6 Injection Timing. ● P06B9…

18-020-25 REV. B ↗

RAM · 2025-09-30

Flash: Powertrain Control Module (PCM) Updates *Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle must exhibit/set one or more of the following Diagnostic Trouble Codes (DTCs):** ● **P0263 - 00 Cylinder 1 Contribution/balance. ● P0266 - 00 Cylinder 2 Contribution-balance. ● P0269 - 00 Cylinder 3 Contribution/balance. ● P0272 - 00 Cylinder 4 Contribution/balance. ● P0275 - 00 Cylinder 5 Contribution/balance. ● P0278 - 00 Cylinder 6 Contribution/balance. ● P026B - 00 Injection Timing Performance. ● P020A - 00 Cylinder 1 Injection Timing. ● P020B - 00 Cylinder 2 Injection Timing. ● P020C - 00 Cylinder 3 Injection Timing. ● P020D - 00 Cylinder 4 Injection Timing. ● P020E - 00 Cylinder 5 Injection Timing. ● P020F - 00 Cylinder 6 Injection Timing. ● P06B9…

OTHERDOC_147 ↗

RAM · 2025-09-05

Powertrain Contol Module Over The Air Update to V2B (Diesel Only) Software Version (FOTA) 2025 - 2026 (DJ) RAM 2500 Pickup 2025 - 2026 (D2) RAM 3500 Pickup 2025 - 2026 (DD) RAM 3500 Cab Chassis 2025 - 2026 (DF) RAM 3500 10K Lb. Cab Chassis2025 - 2026 (DP) RAM 4500/5500 Cab Chassis Customers may experience one or more of the following: - Power Inverter (110V connection) drops out when shifting from P to D - DEF (Diesel Exhaust Fluid) level gauge inaccuracy - Poor cold start performance - Instrument Panel Cluste MIL (Malfunction Indicator Light) ON; Possible P-codes: P0087/P2540/P2543 Fuel Pressure P214D/P242B SCR Temperature P24DA PM Sensor P20EE SCR Efficiency P226C/P2281 Mass Charge Flow P229F System Outlet NOx Sensor P0100 MAF Sensor P203F DEF Level P0423 DOC Efficiency

S2525000002 ↗

RAM · 2025-05-16

Diesel Exhaust Fluid (DEF) Gauge Fluctuates Or Is Erratic. Diagnostic Trouble Code (DTC) P203F – Reductant Level Too Low.

18-034-21 REV. A ↗

RAM · 2021-11-10

P203E and P203F Additional Diagnostic Information This bulletin provides additional information regarding diagnosing Diesel Exhaust Fluid (DEF) issue in extreme cold weather. Diagnostic Trouble Codes (DTCs) P203E - Reductant Level Sensor 1 Circuit Intermittent and/or P203F - Reductant Level Too Low set.

1803421 ↗

RAM · 2021-04-02

P203E and P203F Additional Diagnostic Information This bulletin provides additional information regarding diagnosing Diesel Exhaust Fluid (DEF) issue in extreme cold weather. Diagnostic Trouble Codes (DTCs) P203E - Reductant Level Sensor 1 Circuit Intermittent and/or P203F - Reductant Level Too Low set.

18-034-21 ↗

RAM · 2021-04-02

P203E and P203F Additional Diagnostic Information This bulletin provides additional information regarding diagnosing Diesel Exhaust Fluid (DEF) issue in extreme cold weather. Diagnostic Trouble Codes (DTCs) P203E - Reductant Level Sensor 1 Circuit Intermittent and/or P203F - Reductant Level Too Low set.

P203F00 ↗

VOLVO BUS · 2020-04-01

Repair instructions to address fault codes. P203F00 Reductant Level Low

P203F00 ↗

PREVOST · 2020-04-01

Repair instructions to address fault codes P203F00 Reductant Level Low