A practical overview of the traditional OEM PROXI alignment routine and the fundamentally different FCA PROXI Tool workflow. The tool connects directly over ELM327 or J2534, preserves the original Configuration Code, recalculates CRC/checksums and writes the required ECUs, so a separate PROXI alignment routine is never required after its write. Many people search “proxy alignment”; the FCA term is PROXI.
Concept
What PROXI alignment is
PROXI alignment is a configuration synchronization procedure used on many FCA/Stellantis platforms. It ensures that modules share the same configuration map. You typically encounter it after retrofits, module replacement, or configuration mismatches.
Tool role
What the tool does — with no PROXI alignment afterward
FCA PROXI Tool reads and edits configuration buffers (bytes/bits), recalculates the required CRC/checksums and writes a checksum-correct result directly through ELM327-compatible adapters or J2534 PassThru.
Key feature: the tool keeps the original Configuration Code used for ECU synchronization and writes only to the specific ECU(s) that need the change. The configuration identity remains consistent, so the vehicle does not enter a PROXI mismatch state and a separate PROXI alignment routine is not required.
Workflow
Typical workshop workflow
Read the configuration with Direct Connect over ELM327 or J2534.
Open the buffer in FCA PROXI Tool (Standard / Advanced / PROXI Map Editor).
Edit bytes/bits (including bit-level editing when needed).
Save output with CRC recalculated to keep the file consistent.
Write back and validate over Direct Connect (ELM327 or J2534).
More than alignment: full diagnostics and Fast Parameters
FCA PROXI Tool is an all-in-one suite - the same app that edits PROXI configuration also talks to the car and diagnoses it.
Diagnostics
Full vehicle diagnostics
Scan every module, read and clear DTCs, view freeze-frame and topology, and decode EOL rejection reasons by parameter name when a write is refused. See diagnostics.
Fast Parameters
Named parameters from the factory database
Pick values by name with correct value lists for your exact platform and body, written against a verified bit map so one change never disturbs its neighbours. More on Fast Parameters.
Adapters
ELM327 or J2534, with CAN-FD
Works over an ELM327-compatible adapter or J2534 PassThru; CAN-FD modules need an FD-capable adapter. Adapter guide.
Model-specific guides (new platforms)
If you work mostly on the newest platforms, start here. These pages focus on the practical symptoms, access realities, and workflows for each model.
Jeep
Jeep Grand Cherokee WL
PROXI (proxy) alignment symptoms and a configuration-first workflow for WL / WL74 platforms.
PROXI (proxy) alignment / configuration mismatch guide for Hornet, with a configuration-first workflow (keep Configuration Code, checksum-correct output, write only to selected ECUs). Includes SGW access notes.
People use “PROXI alignment” to describe two related things: the vehicle configuration data (often called PROXI configuration)
and the alignment procedure that synchronizes that configuration across modules. Mixing those two is where most confusion starts.
Short version: the alignment routine copies the current vehicle configuration from the BCM to other modules.
Traditional workflows commonly run it after a retrofit, module replacement or configuration mismatch. FCA PROXI Tool does not: its write is already synchronized.
External sources used for factual claims on this page.
What PROXI alignment is (and what it is not)
On many FCA/Stellantis vehicles the Body Control Module (BCM) holds a “feature map” style configuration.
The alignment procedure is the part that propagates that configuration to other modules, so they agree on what equipment is present and how it should behave.
Definition
Alignment = synchronization
The alignment routine copies the current vehicle configuration from the BCM to other modules on the network.
That is why it’s commonly used after changes: when modules disagree, the car complains until the configuration is consistent again.
BCM as “source of truth”Copies config to other ECUsSolves mismatches
Clarification
Editing ≠ alignment
Editing is changing bytes/bits in the configuration buffer (for example: retrofit flags, regional settings, module presence).
Alignment is the diagnostic procedure a traditional OEM workflow may run to push configuration across modules.
FCA PROXI Tool reads, edits and writes the configuration directly over ELM327 or J2534, preserves the original Configuration Code, recalculates CRC/checksums and verifies the result. The write is already synchronized, so no separate alignment routine is required.
“PROXI alignment” is an FCA term used on many (not all) platforms and model-years.
The exact routine name, menu location, and required network adapters can differ between vehicles and diagnostic software versions.
Where you see it in official tooling: in wiTECH documentation and TSB workflows the Proxi Alignment / Proxi Configuration Alignment routine is referenced under the BCM and may appear in areas like “Miscellaneous Functions” or “Vehicle Preparations”, depending on context and software version.
When traditional/OEM workflows run PROXI alignment
The alignment routine is commonly used after you change equipment or module presence. Think of it as “the car learning the new lineup”.
In a traditional workflow that changes configuration identity, skipping the prescribed OEM sync can leave mismatch symptoms. This does not apply to an FCA PROXI Tool write, which preserves identity and remains synchronized.
After hardware change
Retrofits and module replacement
Typical triggers include retrofits (radio, cluster features, cameras), replacing a module, restoring a BCM configuration, or resolving a communication/config mismatch after repairs.
Many professional diagnostic workflows explicitly call for Proxi Alignment after certain procedures.
After config change
Configuration mismatch conditions
If the BCM configuration does not match what other modules report (or a “new” module is detected), some vehicles indicate a mismatch until alignment is completed.
This is one reason workshops keep a repeatable “read → edit → write → align” playbook.
Cost control
Avoiding trial-and-error
A clean configuration file with consistent checksums reduces guesswork.
You want each change to be intentional, traceable, and reversible, especially when you’re doing multiple retrofits in the same session.
Common symptoms of a PROXI / configuration mismatch
Symptoms depend on model and platform, but there are patterns that keep repeating in real workshops.
Always confirm with diagnostics, because a warning light can have multiple causes.
Dash indicator
Flashing odometer (on many FCA platforms)
A flashing odometer is widely documented as a sign of configuration mismatch or an unrecognized/unaligned module.
It is often seen after head unit swaps or aftermarket installs when the network “sees” something different than what the BCM configuration expects.
Diagnostics
Module configuration status not “aligned”
Some diagnostic tools show a per-module status table for PROXI configuration (configured / not configured / not applicable).
If one or more modules report mismatch, alignment is part of the standard repair path.
Network side effects
Feature missing or wrong behavior
If the configuration says a feature is present but a module does not accept it (or vice versa),
you can see missing menu items, disabled options, or warnings after a retrofit until the configuration is consistent again.
Important: PROXI alignment is not a magic “clear all” button. If a module is genuinely faulty, has communication issues, or the vehicle has an unrelated DTC,
alignment may complete but the problem may remain. Use it as part of diagnosis, not as a substitute for diagnosis.
FCA PROXI Tool workflow: no alignment afterward
This is the workshop-friendly sequence most techs follow when configuration changes are involved.
It keeps your changes controlled and reduces the “why did that checkbox break something else” moments.
Why FCA PROXI Tool does not require PROXI alignment: the synchronization check is based on the Configuration Code, while feature behavior lives in CRC-protected configuration data. FCA PROXI Tool changes the required data and recalculates CRC without changing the original Configuration Code. The modules continue to agree on the same identity, no mismatch state is triggered, and no separate alignment pass is required.
Step 1
Read and archive the original configuration
Start by reading the configuration buffer with Direct Connect (ELM327/J2534) or your diagnostic workflow.
FCA PROXI Tool automatically creates and preserves an untouched backup of the original configuration when it is read; no manual backup step or prompt is required.
Step 2
Edit the configuration intentionally
Change only what you need (module presence, retrofit flags, regional features).
When you can, prefer bit-level edits with clear visibility into what changes inside the byte.
FCA PROXI Tool is designed around this exact step: Standard view for speed, Advanced view for precise control, and a map-driven editor when you want structure.
Step 3
Keep the file consistent (checksum/CRC)
In many FCA diagnostic workflows, the configuration buffer is protected by a checksum (often CRC).
If you modify bytes but do not regenerate the checksum correctly, you can end up with invalid output that is rejected by tooling or behaves unpredictably.
A dedicated editor that recalculates checksums automatically saves time and prevents avoidable failures.
Step 4
Write back to needed ECUs and validate
Write the updated configuration using your established diagnostic method and confirm the change took effect.
Clear and re-check DTCs where appropriate, and verify the target features on the vehicle.
Traditional/OEM tools that run PROXI alignment
The alignment routine itself is performed by diagnostic software. Which tool you use depends on the vehicle and what networks it exposes through OBD.
Below are commonly referenced options, but always confirm coverage for the exact model and year.
OEM
wiTECH (FCA/Stellantis)
OEM-level workflows and some official service bulletins reference Proxi Alignment / Proxi Configuration Alignment as part of repair or module service routines.
Menu placement can vary by context and version, but BCM is commonly where the routine is accessed.
OEM
CDA (Chrysler Diagnostic Application)
CDA is used in some Chrysler/Jeep/Ram dealership environments as part of service diagnostics. Where supported for a given platform/year,
it can provide access to configuration routines and related procedures. Availability and menu placement vary by vehicle generation.
Aftermarket
MultiECUScan (MES)
MultiECUScan is widely used for Fiat/Alfa/Lancia diagnostics and includes a PROXI alignment function on supported vehicles.
It typically guides the user through the procedure and prompts for any required adapters.
Aftermarket
AlfaOBD
AlfaOBD explicitly lists Proxy alignment and configuration adjustment capabilities in its feature set.
It’s commonly used by enthusiasts and workshops on supported FCA vehicles with appropriate interfaces.
Mobile/DIY
Other diagnostic platforms
Some third-party apps and scanners offer a “Proxi Configuration Alignment” routine on certain models,
often presenting a module status table and a guided routine. Coverage and reliability vary across brands and tool versions.
Reminder: this page is about understanding the concept and building a consistent workflow.
Step-by-step button sequences are tool-specific and can change, so always follow the prompts inside your diagnostic software.
In workshop practice, the easiest way to waste time is to edit configuration bytes and ignore file integrity rules.
Configuration buffers are commonly checksum-protected (often CRC). When you change bytes, the checksum must match the new content.
Problem
“I changed one flag and now everything is weird”
The root cause is often not the flag itself, but the file integrity after editing.
Incorrect checksum handling can lead to invalid output files or changes that don’t behave as expected.
Solution
Use an editor that makes integrity automatic
FCA PROXI Tool recalculates CRC for supported buffers and marks modified bytes so you can see what changed.
That’s not “fancy UI”. It’s the boring part you want 100% correct every time.
Good practice
Keep change sets small and reversible
Do one logical change set, save, validate, and only then move on.
When troubleshooting, smaller diffs are faster to reason about than “I toggled 30 things and hoped”.
Changelog
This page is an educational guide about PROXI alignment. Product release notes are published separately and also shown inside the app (built‑in update checker).
Where to read it:changelog.json (machine‑readable) and the in‑app changelog screen.
If you’re evaluating the tool for workshop use, the changelog is the best place to see what changed between versions.
Need a clean way to edit PROXI configuration?
FCA PROXI Tool covers the complete “read → edit → checksum → write → verify” workflow. It preserves Configuration Code and writes a synchronized result, so no separate PROXI alignment routine follows.
Independent third‑party software. Not affiliated with FCA/Stellantis.
Short, no-drama answers to questions that come up in real jobs.
Does PROXI alignment “program” a module?
It synchronizes configuration (feature map) across modules. It does not replace ECU flashing or firmware programming.
If a module needs software updates, that’s a different procedure.
Why is the BCM mentioned so often?
Many descriptions of PROXI alignment treat the BCM as the module that holds the current vehicle configuration and distributes it to other ECUs during the routine.
My odometer is flashing. Is it always PROXI?
It’s a common indicator of configuration mismatch on many FCA platforms, but it’s not the only possible cause of problems.
Confirm with a diagnostic scan and the tool’s configuration status view if available.
Can I edit the configuration and not run PROXI alignment?
Yes. FCA PROXI Tool preserves the original Configuration Code used for ECU synchronization and recalculates CRC correctly. The modules continue to agree on the same identity, so the vehicle does not enter a PROXI mismatch state and a separate alignment step is not required. The tool reads, edits and writes the result directly over ELM327 or J2534.
Where does FCA PROXI Tool fit in?
FCA PROXI Tool connects directly over ELM327 or J2534: it reads the configuration, lets you change parameters in a controlled way (Standard, Advanced or Compare), recalculates checksums, and writes back - with a full diagnostics module to confirm. It does not run the OEM flash/programming routine.
References (public sources)
This page avoids “forum mythology” where possible. The sources below are used for the core factual statements
(what the routine does, typical triggers, and where it appears in wiTECH workflows).
Definition
Snap‑on Technical Focus: “What Is Proxi Alignment?”
