P0513 on 2018-2020 Ram 2500/3500: Invalid Key and No-Start Fixes

What's Unique About the 2018-2020 Ram 2500/3500

For this generation of Ram trucks, the P0513 code is closely tied to the sensitive digital communication between the key fob, the Radio Frequency Hub (RFH), and the main computer (PCM). A key point of failure, highlighted by a manufacturer Technical Service Bulletin (TSB S2208000073), is software synchronization. The code can appear after a PCM is replaced or its software is updated if the key reprogramming procedure isn't performed correctly, emphasizing the need for proper programming during major electronic repairs. A real-world failure pattern noted on forums involves water intrusion from a leaking third brake light shorting out the RFH module, which is located on the rear wall of the cab.

Generation note: The 2018 model year is the end of the fourth generation Ram HD (DJ/D2), while 2019-2020 marks the beginning of the fifth generation (DT). A key difference is the key fob battery: 2018 models typically use a CR2032, while 2019 and newer models use a CR2450. The underlying security system functions similarly, but component locations and part numbers may differ. The 4th gen often uses a Wireless Ignition Node (WIN), while the 5th gen uses a more integrated RF Hub with push-button start.

Symptoms You May Notice

• Engine cranks but will not start
• Engine starts and immediately stalls
• Flashing red security light on the instrument cluster
• Dashboard message such as "Key Not Recognized".
• Remote key fob functions (lock/unlock) may not work

Most Likely Causes

1. Weak or Dead Key Fob Battery 🔴 High Probability Key fobs are powered by small batteries that wear out over time with normal use.
   How to confirm: Try starting the vehicle with your spare key. If the spare key works, the issue is with the primary key. You can also try replacing the battery in the non-working fob (CR2032 for 2018, CR2450 for 2019-2020). For push-to-start models, holding the 'dead' fob against the start button may allow the truck to start, confirming a weak battery.
   Typical fix: Replace the battery inside the key fob.
   Est. part cost: $5-$15
2. Faulty or Damaged Key Fob 🟡 Medium Probability The internal transponder chip in the key can be damaged from being dropped, exposure to water, or electronic failure. Keys can also lose their programming due to electronic glitches.
   How to confirm: If a new battery doesn't solve the issue and the spare key works perfectly, the original key fob is likely faulty.
   Typical fix: The key fob must be replaced and programmed to the vehicle by a dealer or qualified locksmith.
   Est. part cost: $150-$400
3. PCM/Module Programming Issue 🟡 Medium Probability As noted in TSB S2208000073, this code can be set after the PCM is replaced or reflashed if the security keys are not properly relearned by the system. The PCM defaults and loses the vehicle's security code until the routine is run.
   How to confirm: This issue will appear immediately after a PCM replacement or software update. Diagnosis requires a dealer-level scan tool (like wiTECH) to verify the VIN and security key data stored in the PCM, BCM, and RF Hub.
   Typical fix: Perform the 'PCM Replaced Procedure' or 'Proxy Configuration Alignment' using a compatible scan tool to synchronize all security modules.
   Est. part cost: $0 (if part of original repair), $100-$250 for reprogramming service
4. Faulty Radio Frequency Hub (RFH) Module ⚪ Low Probability The RFH is the receiver for the key's signal. Like any electronic module, it can fail. A specific failure pattern for 5th generation trucks is water damage from a leaking third brake light seal, which drips onto the RFH module mounted on the cab's back wall.
   How to confirm: If no keys will start the vehicle and the key fob batteries are good, a technician will use a scan tool to check for communication with the RFH module. A lack of communication or internal fault codes in the RFH points to its failure. Visual inspection for water damage at the module's location is also recommended.
   Typical fix: Replace the RFH module and program it to the vehicle, along with all existing keys. If water intrusion was the cause, the source of the leak (e.g., third brake light gasket) must also be repaired.
   Est. part cost: $200-$500 for the module, with one owner reporting a dealer bill of around $1800 for the full repair including diagnosis and programming.

Rare But Worth Checking

• Wiring or Connection Issue: A forum user on RamForum.com reported that cleaning a corroded battery cable connection at the main fuse panel resolved an intermittent P0513 and no-start condition. Poor connections can cause low voltage and disrupt communication between security modules.
• Aftermarket Remote Starter or Alarm: Improperly installed aftermarket systems can interfere with the factory immobilizer communication, leading to intermittent P0513 codes.
• Faulty Powertrain Control Module (PCM): While less common, an internal failure within the PCM can corrupt the security data and cause this code. This is usually diagnosed after all other possibilities have been ruled out.

Diagnosis Steps

1. Check for a flashing red security indicator light on the dashboard, which confirms an active immobilizer issue.
2. Try to start the truck with a known-good spare key. If it starts, the problem is isolated to the first key fob.
3. If the spare key also fails, replace the battery in one of the key fobs (CR2032 for 2018, CR2450 for 2019-2020). Retest.
4. For push-to-start models, try holding the key fob directly against the start/stop button and pressing it. This uses a low-power, short-range antenna that can sometimes overcome a weak fob battery.
5. Inspect the main vehicle battery terminals and the power connection to the under-hood fuse box for any signs of corrosion or looseness.
6. If the problem appeared immediately after a PCM replacement or software flash, contact the service provider as a 'Proxy Configuration Alignment' is likely needed.
7. For further diagnosis, use an advanced scan tool (like wiTECH, Autel, or AlfaOBD) to read codes from the Body Control Module (BCM) and Radio Frequency Hub (RFH), not just the PCM.
8. Using the scan tool, verify that the correct VIN is programmed into the PCM and RFH.
9. If the RFH is not communicating or shows internal fault codes, it is likely the point of failure. Inspect the module and its connector for signs of water damage, especially on 2019+ models.

Parts You'll Likely Need

• Key Fob Battery — This is the most common and simplest fix. The key fob's internal battery dies, preventing it from sending the security code to the truck.
  Trusted brands: Energizer, Duracell
  OEM price range: $5-$15
  Aftermarket price range: $5-$10
• Key Fob / Transponder Key (OEM #68508720AA (example for 2018 Fobik) or 68547361AA (example for 2019+)) — If the key's internal transponder chip fails or is damaged, the key must be replaced and programmed.
  Trusted brands: Mopar
  OEM price range: $250-$400
  Aftermarket price range: $100-$200
• Radio Frequency Hub (RFH) Module (OEM #68365298AH (and superseded numbers)) — This module receives the signal from the key. It can fail electronically or due to water damage, preventing any key from being recognized. Replacement requires professional programming.
  Trusted brands: Mopar
  OEM price range: $200-$500

Related Codes That Often Appear With This One

• U0426-62 (MiniKrypt Error Signal Compare Error) - This code can sometimes accompany P0513 when there is a programming mismatch after a PCM flash.
• B2205-00 (Original VIN Missing/Mismatch) - This code may be found in the RF Hub or BCM if a used module has been installed without proper VIN programming, indicating a module compatibility issue.

Technical Service Bulletins (TSBs) & Recalls

• S2208000073: No Start, After Flash And Or PCM Replace, DTC P0513 Invalid Skim Key Setting

Platform-Specific Known Issues

• TSB S2208000073 specifically calls out that a no-start condition with DTC P0513 can occur after replacing or reflashing the PCM if the key security data is not properly synchronized. The fix requires a 'PCM Replaced Procedure' or 'Proxy Configuration Alignment' with a dealer scan tool.
• A documented failure pattern on 5th Gen (2019+) trucks is water leaking from the third brake light gasket, dripping down the rear of the cab, and shorting out the RFH module. This requires replacing the module and fixing the leak to prevent a recurrence.

Mechanic-Grade Diagnostic Values

• RF Hub Module Power Supply Voltage — expected: 10.0V - 16.0V (Battery Voltage). Failure: No voltage or significantly low voltage indicates a power supply issue to the module.
• RF Hub Module Ground Circuit Resistance — expected: < 5.0 Ohms. Failure: High resistance (> 5.0 Ohms) or an open circuit (OL) indicates a bad ground connection, which can cause intermittent operation or complete failure.

Hidden / Shadow Codes Worth Checking

• B1A25: Invalid SKIM Key: This code is set in the Body Control Module (BCM) or RF Hub when it determines the key's transponder signal is invalid. It is the direct corresponding body code to the P0513 powertrain code. (see via Requires a professional scan tool (like wiTECH or Autel) capable of reading codes from the BCM or RFH, not just the PCM.)
• B2205-00: Original VIN Missing/Mismatch: This code is set in a security module like the RF Hub when it is installed on a vehicle and the VIN it reads from the PCM does not match the VIN it has stored. It confirms a module programming or compatibility issue, often seen when using used parts. (see via A dealer-level scan tool like wiTECH or a high-end aftermarket scanner (like AlfaOBD) capable of reading BCM/RFH module data.)

Scan Tool Commands That Help

• wiTECH or AlfaOBD: Proxy Configuration Alignment — This is the primary function required after replacing a major module (PCM, BCM, RFH) or after a PCM flash that triggers P0513. It re-synchronizes the configuration data across all CAN bus modules. An incorrect configuration is often indicated by a flashing odometer.
• wiTECH: PCM/ECM/ESL replace — This specific routine, found under the BCM 'Misc. Functions' menu, must be run after replacing the PCM to transfer the security information from the RF Hub to the new PCM, as outlined in TSB S2208000073.
• wiTECH: RF Hub Replace — This routine is used after installing a new RF Hub to initialize it with the vehicle's other modules and program the existing keys to the new hub.
• AlfaOBD: RF-Hub reset/replace — This is an aftermarket tool function that serves a similar purpose to the wiTECH 'RF Hub Replace' routine. It is used to initialize a new RF Hub. Users report needing the vehicle's 4-digit security PIN to complete this procedure.

Wiring & Ground Locations

• Radio Frequency Hub (RFH) Module — For 5th Gen (2019+) models, the RF Hub is located on the rear wall of the cab, below the rear window. Access requires removing the rear seat. For 4th Gen (2018) models, it is in a similar location, on the back wall of the cab behind the rear seat.. This is the central receiver for the key fob signal. Its location on 5th Gen trucks makes it highly susceptible to water damage from a leaking third brake light or rear window seal, a common cause of failure leading to P0513.
• RF Hub Fuse (2018) — In the under-hood fuse box (Power Distribution Center), fuse F52 (a 5-amp fuse) powers the Radio Frequency Module on 2018 models.. A blown fuse will cut all power to the RF Hub, preventing it from reading the key and causing a no-start with P0513.
• Body Control Module (BCM) Ground — The BCM is located high up in the driver's side dash, near the parking brake pedal. It has multiple ground points to the chassis in that area.. The BCM is a critical part of the security handshake. A poor ground can cause intermittent communication issues between the BCM, RF Hub, and PCM, leading to a false P0513 code.

Real Owner Repair Stories

• 5thGenRams Forum user (2019+ Ram 1500 (platform shared with 2500/3500)) — Vehicle was un-startable, even when pressing the key fob to the start button. No prior symptoms.
  ❌ Tried (didn't work) Pressing key fob to start button
  ✅ What actually fixed it The dealer diagnosed and replaced a failed RF Hub. The user noted there was no water leak present, indicating the module can fail on its own from internal electronic failure. The total repair cost was around $1800 at the dealership.

OEM Part Supersession History

• 68365298AA, AB, AC, AD, AE, AF, AG → 68365298AH — Part revisions to improve reliability or address manufacturing issues.
  Heads up: While all listed part numbers are for the same component, it is always recommended to use the latest available revision (AH) when replacing the module. Some vendors note this part is discontinued, so sourcing may be difficult.

Model Year Variations Within This Range

• 2018 (4th Gen DJ/D2): Uses a Wireless Ignition Node (WIN) system in some configurations, which is functionally similar but may have different part numbers and diagnostic procedures than the 5th Gen RF Hub. The key fob uses a CR2032 battery. The overall cab and interior are different, affecting module and wiring locations.
• 2019-2020 (5th Gen DT): Uses the integrated Radio Frequency Hub (RFH) system. The key fob uses a larger CR2450 battery. The RFH module is known to be vulnerable to water leaks from the third brake light and rear window, a design-related issue for this generation.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• CP4 High-Pressure Fuel Pump Failure (6.7L Cummins) 🔴 High — Common on 2019-2020 models, leading to a major recall. Failure can be catastrophic to the entire fuel system. (Ref: Recall Y78 / NHTSA 21V880)
• Front End "Death Wobble" 🔴 High — A well-known issue on solid front axle Ram trucks, often triggered by worn track bar bushings, steering components, or improper alignment, typically between 45-65 mph.
• Uconnect 8.4"/12" Screen Delamination/Malfunction 🟠 Medium — The screen can delaminate, causing 'ghost touches' and erratic behavior. Also subject to a recall for the rearview camera image staying on. (Ref: Recall W30-W37 / NHTSA 20V191)
• Transmission Problems (2018 model year) 🟠 Medium — Some 2018 models experienced issues with the Aisin transmission, including harsh shifting, slipping, and potential failure.
• Electrical System Faults (2019 model year) 🟠 Medium — Reports of various electrical issues, including malfunctioning interior accessories and wiring problems, were more common on the 2019 models. (Ref: Multiple TSBs, e.g., #10181643, #10162485)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: Used parts are generally not recommended for this repair due to security programming. The only components that are safe to source used are physical items like wiring connectors or the plastic housing for a module if only the housing is damaged.

OEM-only on this vehicle (don't cheap out):

• Radio Frequency Hub (RFH) Module
• Powertrain Control Module (PCM)
• Body Control Module (BCM)
• Key Fob

Aftermarket brands forum-validated for this vehicle:

• AlfaOBD (Software for diagnosis and programming)
• OBDLink MX+ (Hardware interface for AlfaOBD)

Brands owners have reported issues with on this vehicle:

• Used RF Hubs or PCMs from junkyards. They are VIN-locked to the original vehicle and cannot be reprogrammed by a dealer. While specialized third-party services exist to 'virginize' or change the VIN in these modules, it is a complex process not suitable for DIY or standard shop repair.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• UXXXX — Communication codes often appear when the Radio Frequency Hub (RFH) is damaged by water or fails internally, preventing it from talking to the BCM or PCM.

Frequently Asked Questions