U0019 on 2015-2017 Ram ProMaster: CAN B Bus Failure Causes and Fixes

What's Unique About the 2015-2017 Ram PROMASTER

The 2015-2017 Ram ProMaster is particularly known for setting this code erroneously due to software issues within the Body Control Module (BCM). Ram has issued multiple Technical Service Bulletins (TSBs), such as 08-104-15 and 08-230-22, specifically to address this condition by updating the BCM software, with a strong focus on the 2015 model year. Unlike many other vehicles where a U-code immediately points to a wiring or module hardware failure, on this specific ProMaster, the first suspect should always be outdated BCM software.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp) is on.
• Erratic or non-functional door locks or key fob.
• Turn signal indicators flashing at double the normal speed (hyper-flash), sometimes accompanied by a "Bulb out" message for LED turn signals.
• False "bulb out" messages or warning icons in the instrument cluster.
• Fog light indicator staying on with high-beams.
• Odometer flashing (indicates a proxy configuration issue 🎬 Watch: How to fix a flashing odometer with proxy alignment.).
• Radio or infotainment system not working.
• Power windows not functioning.
• Other random electrical issues related to body functions.

Most Likely Causes

1. Body Control Module (BCM) Software Needs Updating 🔴 High Probability → Shop Body Control Module This is a well-documented issue, especially for the 2015 model year. Ram has released several TSBs (e.g., 08-104-15, 08-230-22, 0810517) specifically to correct erroneous U0019 codes by reprogramming the BCM. These TSBs also address other software-related symptoms like key fob issues and incorrect fog light behavior.
   How to confirm: A Ram dealership or a qualified independent shop with a wiTECH scan tool can check the current BCM software version against the latest available version referenced in the TSBs. The dealer can look up applicable TSBs by VIN.
   Typical fix: Reprogramming (flashing) the BCM with the updated software. This is a software-only repair that typically takes less than an hour. A Proxy Alignment procedure must be performed after the flash.
   Est. part cost: $0
2. CAN B Bus Wiring or Connector Issue 🟡 Medium Probability Wiring harnesses can be susceptible to damage from chafing, moisture intrusion, or corrosion over time. Aftermarket installations can also damage wiring if harnesses are not properly secured. A single bad connection or wire can bring down the entire network.
   How to confirm: Visually inspect the CAN bus wiring harness for any signs of damage, particularly around the BCM (located near the steering column), behind the glove box, and in door jambs. A technician can use a multimeter to check for proper resistance (around 60 ohms between CAN High and CAN Low pins at the OBD-II port) and test for shorts to power or ground.
   Typical fix: Repairing the damaged section of wiring or cleaning/replacing a corroded connector. In one documented case, a CAN wire was chafed through by the sharp edge of the dashboard after an aftermarket device was installed improperly.
   Est. part cost: $5-$50
3. Faulty Body Control Module (BCM) ⚪ Low Probability → Shop Body Control Module
   How to confirm: This is diagnosed by exclusion. If the BCM software is up-to-date and all wiring, connectors, and other modules on the CAN B bus test good, the BCM itself is the likely culprit.
   Typical fix: Replacing the Body Control Module. The new module must be programmed to the vehicle's VIN and a 'Proxy Alignment' procedure must be performed to synchronize it with other modules on the network. This is not a plug-and-play part and requires dealer-level tools. 🎬 See this walkthrough on replacing and programming a ProMaster BCM.
   Est. part cost: $300-$500

Rare But Worth Checking

• Faulty module on the CAN B network (other than BCM): Any module on the network (like a door module, radio, or even trailer tow module) can fail and disrupt communication by shorting the bus. A technician can diagnose this by unplugging modules one by one to see if communication is restored.
• Corroded Fuse Box / Power Distribution Center: Though less common, corrosion under the main fuse box can damage the integrated CAN bus wiring, leading to communication faults. A visual inspection for water damage and pulling on wires to check for corrosion is a valid diagnostic step.

Diagnosis Steps

1. Connect a professional scan tool (like wiTECH) and check for Diagnostic Trouble Codes (DTCs) in all modules, not just the engine computer. Note which modules are not communicating.
2. Using the VIN, check for open TSBs related to U0019. For 2015-2017 ProMasters, specifically look for TSBs #08-104-15, #0810517, and #08-230-22.
3. If a relevant TSB exists and the BCM software is outdated, perform the BCM software update. This is the highest probability fix for a 2015 model. A Proxy Alignment must be run after the flash.
4. If the software is up-to-date or the update does not fix the issue, perform a visual inspection of the CAN B bus wiring harness. Look for obvious damage, corrosion, or loose connectors, particularly behind the glove box, near the BCM by the steering column, and in door jambs.
5. Using a multimeter, measure the resistance between Pin 3 (CAN B Low) and Pin 11 (CAN B High) at the OBD-II port with the battery disconnected. 🎬 Watch: How to perform a quick CAN bus multimeter check. A healthy network should read approximately 60 ohms. A reading of 120 ohms suggests a missing terminating resistor or an open circuit.
6. If resistance is incorrect, check the wiring and terminating resistors. If resistance is low, check for a short between the CAN wires.
7. If wiring and resistance are correct, the fault may lie with a module on the network. A technician can isolate the faulty module by disconnecting them one at a time and re-checking network function. The BCM is a common point of failure after software and wiring have been ruled out.
8. If the BCM is replaced, it must be programmed with the vehicle's VIN and a Proxy Alignment must be performed to restore communication with all other modules.

Parts You'll Likely Need

• Body Control Module (BCM) Software Update — This is the most common and manufacturer-recommended fix for erroneous U0019 codes on the 2015 ProMaster, as documented in multiple TSBs.
  OEM price range: $100-$200 (Labor for reprogramming).
  Aftermarket price range: N/A
• Body Control Module (BCM) (OEM #68245054AD (Example for 2016, part numbers are VIN specific)) — If a software update and wiring checks do not resolve the issue, the BCM hardware itself may have failed.
  Trusted brands: Mopar
  OEM price range: $300-$500.
  Aftermarket price range: $200-$400 (Remanufactured/Cloned).

Technical Service Bulletins (TSBs) & Recalls

• 0810517: Addresses MIL illumination for U0019-01 on 2015 MY ProMasters and provides software enhancements for key programming.
• 08-230-22: Supersedes a previous TSB and addresses U0019-01 on 2015 MY ProMasters, along with other electrical issues like key fob problems and bulb out warnings.
• 08-104-15: Specifically calls out a BCM software update to fix erroneous U0019-01 DTCs and a fog light indicator issue on 2015 models.

Platform-Specific Known Issues

• Multiple Technical Service Bulletins (TSBs), including #0810517, #08-230-22, and #08-104-15, have been issued by Ram to address an erroneous U0019 code on 2015 models via a Body Control Module (BCM) software update.
• The BCM is located in the instrument panel, adjacent to the steering column on the driver's side.
• The ProMaster is based on the Fiat Ducato, which also reports U0019 for CAN bus faults, though not specifically linked to a software bug in the same way as the 2015 ProMaster.

Mechanic-Grade Diagnostic Values

• CAN B Bus Network Resistance — expected: ~60 Ohms. Failure: A reading of ~120 Ohms indicates an open circuit or a missing terminating resistor. A reading significantly less than 60 Ohms indicates a short between the CAN high and low wires.
• CAN B Bus Test Location — expected: Between Pin 3 (CAN B / IHS Low) and Pin 11 (CAN B / IHS High) at the Data Link (OBD-II) Connector.. Failure: N/A - This is the physical location for testing.

Hidden / Shadow Codes Worth Checking

• U0019-01: CAN B Bus - General Electrical Failure. This is the specific variant of the code cited in manufacturer TSBs for the 2015 ProMaster software issue. (see via Professional scan tools like the dealer's wiTECH system.)
• U0019-88: Bus Off. This sub-type indicates the network is not available because a module has shut down communication due to excessive errors. (see via Professional scan tools that can read Failure Type Bytes (FTBs).)
• U0019-87: Missing Message. This sub-type is used when an expected message from a module is not received. (see via Professional scan tools that can read Failure Type Bytes (FTBs).)

Scan Tool Commands That Help

• wiTECH 2: Proxy Configuration Alignment — This procedure is mandatory after replacing or reprogramming the BCM. It synchronizes the new/updated module with all other modules on the vehicle's network. Failure to perform this will result in a flashing odometer and persistent communication DTCs.
• wiTECH 2: Restore BCM proxi configuration — Used in conjunction with the Proxy Alignment procedure, this function is found in the BCM's 'Misc. Function' tab and is part of the official TSB repair process.
• wiTECH or equivalent: Clear All DTCs — This should be the final step after any reprogramming event to clear faults that were set during the flashing process.

Wiring & Ground Locations

• Body Control Module (BCM) — Inside the cabin, on the driver's side, tucked within the instrument panel adjacent to the steering column.. The BCM is the central hub for the CAN B bus and the primary source of the U0019 code on this vehicle, either through software or hardware failure.
• CAN B Bus at OBD-II Port — Pins 3 (CAN B Low) and 11 (CAN B High) of the Data Link Connector.. This is the most accessible point for a technician to perform initial network resistance and voltage checks with a multimeter.
• Engine/Chassis Ground — A critical ground path runs from the engine block (e.g., a starter motor bolt) to the chassis, often to a point under the fuse box.. A poor engine ground can cause a wide range of electrical issues, including communication faults, by creating unstable voltage references for various modules.

Real Owner Repair Stories

• Fiat Ducato Forum user (Fiat Ducato (ProMaster platform mate) with aftermarket Android head unit installed.) — Flashing odometer and clock that could not be set.
  ❌ Tried (didn't work) Preparing to perform a dealer-level Proxy Alignment using special software and adapters.
  ✅ What actually fixed it The owner went into the Android head unit's factory settings menu and changed the 'Car Model' or CAN bus protocol setting. After trying a different protocol, the clock and odometer immediately stopped flashing and began communicating correctly with the vehicle.
• MotorhomeFun Forum user (Fiat Ducato based Motorhome) — Flashing odometer.
  ❌ Tried (didn't work) Multiple vehicle restarts.
  ✅ What actually fixed it The user noted that a weak vehicle battery after a period of storage can cause CAN bus anomalies like a flashing odometer. Often, fully charging the battery and performing several key cycles (up to 5 restarts) can clear the minor communication error without needing a dealer visit.

OEM Part Supersession History

• 68245054AB → 68245054AC, 68245054AD, 68245054AE, 68245054AF — Standard part revisions for bug fixes and hardware improvements.
  Heads up: While these part numbers are listed for 2016 Ram trucks (1500/2500/3500), they may be used in ProMaster vans. Always confirm the correct part number with a dealer using the vehicle's VIN before ordering.

Model Year Variations Within This Range

• 2015 only: The erroneous U0019-01 code caused by a software glitch is specifically called out for the 2015 model year in TSB #08-230-22. The primary fix is a BCM software update.
• 2017 only: TSB #08-230-22 provides software updates for the 2017 model year to address different issues, such as key fob, horn delay, and parking lamp problems, but not specifically for the U0019 code.