U1200 on 2013-2015 Fiat 500e: Lost Communication With Power Inverter Module

What's Unique About the 2013-2015 Fiat 500

This code is exclusive to the Fiat 500e electric model and will not be found on gasoline-powered Fiat 500s. The vehicle's architecture relies on constant communication between the high-voltage powertrain components (like the PIM) and safety systems (like the ABS module). Fiat Chrysler Automobiles (FCA) has issued both recalls and technical service bulletins related to the PIM and its software, indicating known issues with this system on early 500e models. The electric powertrain components were supplied by Bosch.

Diagnostic Flowchart

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Symptoms You May Notice

• ABS warning light on
• Electronic Stability Control (ESC) warning light on
• "Service Vehicle Soon" or other powertrain warning messages
• Vehicle may enter a reduced power "limp home" mode, often with a turtle icon on the dash
🎬 Watch: How a simple electronic glitch can trigger limp mode.
• Potential for sudden loss of propulsion
• Vehicle may not start or be 'Ready' to drive
• Flashing odometer, which can indicate a CAN bus or module communication problem requiring a 'Proxy Alignment'

Most Likely Causes

1. Software Incompatibility/Glitch 🔴 High Probability FCA issued TSB #08-045-16 specifically to address this and other related communication codes by updating module software. Recalls for the PIM and related control units also point to software and hardware vulnerabilities. This is the most common and least expensive fix.
   How to confirm: A Fiat dealer or a properly equipped independent shop using a wiTECH scan tool can check the vehicle's software calibration levels against the latest versions and determine if TSB #08-045-16 is applicable and has been performed.
   Typical fix: Reprogramming the affected modules (ABS, RBC, PIM) with the latest factory software. This is referred to as 'flashing' the module.
   Est. part cost: $0-$250
2. Low 12V Battery Voltage 🟡 Medium Probability → Shop Vehicle Battery Like many modern EVs, the 500e is very sensitive to the state of its 12V auxiliary battery. A weak or failing 12V battery can cause a cascade of seemingly unrelated communication faults as modules fail to initialize correctly. Forum users report that leaving the car unused for weeks can lead to a dead 12V battery and a host of communication codes, including U1200, upon trying to start it.
   How to confirm: Test the 12V battery with a multimeter or electronic battery tester. A healthy battery should read approximately 12.6V when the car is off and around 14V when the car is 'Ready' and the DC-to-DC converter is charging it.
   Typical fix: Replace the 12V auxiliary battery and clear all fault codes. 🎬 See this walkthrough on how to change the 12V battery. A full module reset by disconnecting the 12V battery may also be necessary.
   Est. part cost: $150-$300
3. Wiring Harness or Connector Issue 🟡 Medium Probability The CAN bus network wiring can be susceptible to damage from vibration, moisture, or impact. A user on the MHH Auto forum reported ABS communication issues after a front-end collision, indicating the harness routing is vulnerable. The wires for the ABS/wheel speed sensors are also known to fray or break from suspension movement.
   How to confirm: Visually inspect the wiring harness between the ABS module and the Power Inverter Module. Check connectors for corrosion, moisture, or pushed-out pins. A multimeter can be used to check for continuity and resistance on the CAN bus wires (typically twisted pairs).
   Typical fix: Repairing the damaged section of the wiring harness or cleaning/replacing the faulty connector. 🎬 Watch: How to repair wiring connectors and avoid a misdiagnosis.
   Est. part cost: $10-$200
4. Failing Power Inverter Module (PIM) ⚪ Low Probability → Shop Power Converter Early 500e models were subject to a recall (NHTSA #14V-492) for PIMs that could leak coolant internally, causing a short circuit. This can trigger not only communication codes like U1200 but also PIM-specific fault codes like B23AE-00 and coolant leak codes like P0456. Even on post-recall vehicles, out-of-warranty failures occur.
   How to confirm: This is a diagnosis of exclusion. After ruling out software, 12V battery, and wiring, the PIM itself is the prime suspect. Advanced diagnostics with a wiTECH scan tool are needed to monitor PIM data. In some cases, Fiat engineering has required a PIM replacement before they will authorize a high-voltage battery warranty claim, creating a difficult situation for owners.
   Typical fix: Replacement of the Power Inverter Module. This is a very expensive repair, often costing thousands of dollars.
   Est. part cost: $4000-$7500

Rare But Worth Checking

• Failing ABS Module: While the code points to a loss of communication *with* the PIM, the fault is logged *in* the ABS module. It's possible, though less likely, that the ABS module itself is the source of the communication failure. This is rare compared to software or PIM issues.

Diagnosis Steps

1. Check the 12V auxiliary battery to ensure it is fully charged and healthy. Low voltage is a known cause of numerous communication faults on the 500e.
2. Connect a high-level scan tool (like the dealer's wiTECH or AlfaOBD) to read codes from all modules, not just the powertrain.
3. Check for any open recalls or applicable Technical Service Bulletins (TSBs), especially TSB #08-045-16. If the TSB is applicable and hasn't been performed, this is the most likely fix.
4. If software is up to date, perform a full CAN bus network test to check for communication integrity across the system. Check for other 'U' codes in various modules.
5. Visually inspect the wiring harness and connectors between the ABS module and the Power Inverter Module (PIM). Look for any signs of damage, corrosion, or loose connections, especially if the vehicle has had front-end damage.
6. Using a wiring diagram, test the power, ground, and CAN bus circuits at both the ABS module and the PIM connectors. The CAN lines should have approximately 60 ohms of resistance across them when the vehicle is off.
7. If all wiring and software are confirmed to be good, and the 12V battery is healthy, the fault likely lies with either the ABS module or the PIM. Given the platform's history, the PIM is a more common point of failure.

Parts You'll Likely Need

• Power Inverter Module (PIM) (OEM #68728330AA) — This module is the subject of both a recall and TSBs for the 2013-2015 Fiat 500e. It can fail due to internal coolant leaks or other electronic faults, causing communication loss. Replacement is extremely expensive, with some owners being quoted over $7,500 by dealers.
  Trusted brands: Mopar
  OEM price range: $4600-$7500
  Aftermarket price range: $800-$1500 (Used/Remanufactured)
• 12V Auxiliary Battery — A weak 12V battery is a frequent cause of multiple, cascading communication error codes on the Fiat 500e and should be the first component checked.
  Trusted brands: Mopar, Interstate, DieHard
  OEM price range: $200-$300
  Aftermarket price range: $150-$250

Related Codes That Often Appear With This One

• U1487-00 — This code, for 'Implausible Data Received From Regenerative Brake Controller,' is cited in the same TSB (#08-045-16) as U1200 and points to the same cluster of communication issues between the braking and powertrain systems.
• U0001-00 — A general 'CAN C BUS' communication failure code, also mentioned in TSB 08-045-16.
• B23AE-00 — This code indicates a direct 'PIM Fault'. If you see this alongside U1200, the likelihood of a hardware failure in the Power Inverter Module increases significantly.
• C1008-16 / C1200-16 — These codes for 'Battery voltage below threshold' were seen in a forum user's diagnostic report alongside U1200, pointing to the 12V battery as a potential root cause for the communication loss. Note: C1200-16 is a different code from U1200-00.

Technical Service Bulletins (TSBs) & Recalls

• 08-045-16: Flash: CAN C BUS, Implausible Data Received From Regenerative Brake Controller, Lost Communication with Power Inverter Module

Platform-Specific Known Issues

• A recall was issued for 2013-2014 Fiat 500e models because the PIM could leak coolant internally, causing a short circuit and loss of power.
• A separate recall for 2013-2015 models addressed incompatible software between the Electric Vehicle Control Unit (EVCU) and Battery Pack Control Module (BPCM) that could cause the vehicle to shut down after entering

Mechanic-Grade Diagnostic Values

• CAN Bus Network Resistance — expected: Approximately 60 Ohms. Failure: A reading of ~120 Ohms indicates an open circuit or a missing terminating resistor in one module. A reading near 0 Ohms indicates a short between the CAN High and CAN Low wires.
• CAN Bus Voltage (System Active) — expected: CAN High: ~2.5V to 3.0V. CAN Low: ~2.0V to 2.5V.. Failure: Voltages outside these ranges, or voltages that are stuck and not mirroring each other during communication, indicate a bus fault.
• CAN Bus Short-to-Ground — expected: Infinite resistance (Open Line / OL). Failure: Any continuity or low resistance reading indicates a short circuit between the CAN line and chassis ground.

Scan Tool Commands That Help

• wiTECH, AlfaOBD, MultiECUScan: Proxy Alignment Procedure (also called CAN Setup) — This procedure is required to resolve a flashing odometer. A flashing odometer indicates a CAN bus configuration mismatch, which can be caused by a failing module (like the PIM or ABS) or after replacing a network module. Running this procedure forces the Body Control Module to rescan the network and can sometimes restore communication.
• wiTECH (Dealer Tool): Reprogram ABS and RBC modules — This is the specific fix called for in TSB #08-045-16 to resolve codes U1200, U1487, and U0001. It updates the module software to a newer calibration level to correct communication logic errors.

Wiring & Ground Locations

• Power Inverter Module (PIM) — Located in the under-hood area, positioned above the electric motor and underneath the On-Board Charging Module (OBCM).. This is the module that the ABS unit has lost communication with. Its main electrical connectors are buried deep in the engine bay but may be more accessible from underneath the vehicle for inspection.
• ABS Control Module — On gasoline Fiat 500s, it is located on the right side of the engine bay, behind the brake fluid reservoir. The 500e has a similar component layout in this area. It is mounted to the hydraulic pump assembly.. The U1200 fault code is logged in this module. All CAN bus wiring, power, and ground connections to this module must be verified.
• CAN C Network — This is a vehicle-wide data bus, not a single component. It is a twisted pair of wires connecting major control units.. The CAN C bus is the specific network used for communication between the ABS module and the PIM. A wiring diagram shows it connects the ABS, PIM, BCM, BPCM, OBCM, and RBC, meaning a fault in any of these modules or their shared wiring could potentially cause issues.

Real Owner Repair Stories

• YouTube channel 'Out of Spec Garage' (Fiat 500e, year not specified) — Powertrain error message on the dash. The dealer diagnosed it as a failed PIM and quoted $8,000 for replacement.
  ❌ Tried (didn't work) Dealer diagnosis pointed to complete PIM replacement.
  ✅ What actually fixed it The technician found the main electrical connector on the Power Inverter Module was not fully seated. After unplugging the connector and plugging it back in until it audibly clicked into its locked position, all fault codes cleared and the vehicle functioned normally.
• Reddit user on r/Fiat500e (2013 Fiat 500e) — Car would not drive and was stuck in limited power mode after sitting unused for a year. A new 12V battery was installed. The dash showed a strange, static 47% state of charge.
  ❌ Tried (didn't work) Replacing the 12V auxiliary battery.
  ✅ What actually fixed it The consensus from experienced EV technicians was that the high-voltage battery pack had self-discharged below a critical voltage level from being left unplugged for so long, rendering it permanently damaged and unrecoverable. The '47% charge' is a known default error value when the battery management system can no longer get a real reading. The required fix was a complete (and very expensive) high-voltage battery pack replacement.
• Fiat 500e Forum user 'tumbler1900' (2014 Fiat 500e) — The car drives fine but will not charge.
  ❌ Tried (didn't work) Not specified, but the owner was seeking to sell the car rather than attempt further diagnosis.
  ✅ What actually fixed it The dealer diagnosed the car as needing a new Power Inverter Module (PIM). The owner deemed the repair too expensive and decided to sell the vehicle as-is, confirming the PIM as the diagnosed point of failure.

When the Usual Fixes Don't Work

• In one documented case, a dealer misdiagnosed a powertrain error as requiring a complete Power Inverter Module replacement at a cost of $8,000. The actual root cause was an improperly seated electrical connector on the PIM, which was fixed for free by unplugging and replugging it securely. This highlights that even with a history of PIM failures, a simple wiring or connection issue should be thoroughly investigated before condemning an expensive module.

OEM Part Supersession History

• 68655792AA → 68728330AA — Standard part revision and update by the manufacturer.
  Heads up: The new part number (68728330AA) is the correct replacement for the original. No incompatibility is noted; it is a direct replacement.

Model Year Variations Within This Range

• 2013-2014 (specifically vehicles assembled Sept. 24, 2012 - April 4, 2014): These vehicles were subject to NHTSA recall #14V-492 for Power Inverter Modules (PIMs) that could leak coolant internally, causing a short circuit and loss of power. Vehicles outside this range, including 2015 models, were not included in this specific recall.