U0100 A module has stopped hearing from the engine control module over the vehicle network
17 owner reports and 287 manufacturer filings across 87 model years from Cadillac, Chevrolet, Dodge, Fiat and others.
Where U0100 shows up
Source: NHTSA manufacturer communications and complaintsShowing the 25 model years where U0100 appears most; it is on file for 87 in total.
A model year appears here because the code is named in its record, not because every one of these vehicles sets it. Counts are mentions in the federal files, not failure rates — nobody publishes the denominator.
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U0100 by make
The same record, one make at a time: the model years, bulletins and owner reports that name U0100 on that maker’s vehicles.
What it gets filed under
What owners said
Source: NHTSA complaint databaseOwners’ own words, one per nameplate, scrubbed of anything identifying. These are unverified reports filed with NHTSA — they are what was said, not a finding that it was true.
We ran the codes on the jeep and it came back as a U0100 code with the PCM system
The diagnostic scan produced the following active codes: U0100 – Lost Communication With ECM/PCM A U1000 – CAN Communication Circuit P1815 – Manual Mode Switch/Circuit / Computer Supply Voltage These faults indicate a failure in the…
And replacing the battery the first time is what revealed all these issues because we kept getting codes on our obd-ii scanner of P0172, U0038 and U0100
Independent mechanic put scanner in my car days later and code that appeared was “U0100 Lost Communication With ECM/PCM” I looked up my vin # on mopar.com and noticed my vehicle did have a “Important Safety Recall: Reprogram Powertrain…
The transmission service required light comes on Codes are as follows PO776 C1560 U0114 U0100
287 manufacturer filings name U0100. Start with what the maker wrote down.
A code names the test that failed, not the part. A bulletin that names it is often a diagnosis someone has already written down — quote its number at the service desk.
Manufacturer filings that name it
Source: NHTSA manufacturer communicationsService bulletins and campaigns whose filed summary names U0100.
- 09-027-26 Service bulletin2026-09-29 · Engine
- DESCRIPTION Some CX-70 and CX-90 PHEV vehicles may fail to start (enter READY mode) in cold weather, but the vehicle can often be started successfully on the next attempt. This may occur when leakage current between connector terminals causes the MAIN Relay to be falsely detected as ON. As a result, the Battery ECU may incorrectly determine the relay status, preventing READY mode activation and re
- SSM 54333 Service bulletin2025-10-28 · Steering
- Some 2023-2025 F-Super Duty vehicles may exhibit a no crank/no start or intermittent no crank/no start with multiple warning indicators and DTC U0100 stored in the anti-lock brake system (ABS), audio front control module (ACM) and power steering control module (PSCM). This may be due to an incorrectly tightened ground 113 (G113). Inspect G113 for proper connection and tighten to 12 Nm (8.9 ft-lb).
- SSM 54216 Service bulletin2025-09-15 · Electrical System
- Some 2023-2025 F-150 vehicles may exhibit a crank/no start with multiple warning indicators and diagnostic trouble code (DTC) U0100 stored in the audio front control module (ACM), gear shift module (GSM), image processing module A (IPMA), power steering control module (PSCM) and instrument panel cluster (IPC). This may be due to an incorrectly tightened ground 104 (G104). Inspect G104 for proper c
- SSM 54173 Service bulletin2025-08-27 · Electrical System
- Some 2023-2025 F-Super Duty vehicles may exhibit a no crank/no start or intermittent no crank/no start with multiple warning indicators and DTC U0100 stored in the anti-lock brake system (ABS), audio front control module (ACM) and power steering control module (PSCM). This may be due to an incorrectly tightened ground 113 (G113). Inspect G113 for proper connection and tighten to 12 Nm (8.9 ft-lb).
- SSM 53994 Service bulletin2025-06-30 · Power Train
- Some 2023-2025 F-Super Duty vehicles may exhibit a no crank/no start with diagnostic trouble code (DTC) U0100 in various modules. This condition may be due to the ground connection at G113. Inspect G113 for proper connection and tighten to 12 +/- 1.8 Nm. If condition remains after tightening G113, continue with normal diagnostics. Refer to Workshop Manual, Section 303-06 Starting System.
- TSB 25-2071 Service bulletin2025-03-13 · Unknown Or Other
- This article supersedes TSB 21-2405 to update the production fix date. Some of the vehicles listed in the Model statement above may exhibit all of the following conditions: * Illuminated powertrain malfunction indicator (wrench) lamp and/or "Shift System Fault" message * DTC U0103:87 stored in the secondary on board diagnostic module (SOBDMC) Some vehicles may also exhibit DTCs U0100:00, U0121, U0
What U0100 means
Source: SAE J2012 / OBD-IIA module has stopped hearing from the engine control module over the vehicle network.
A stored code names the test that failed, never the part that caused it. It is the starting point of a diagnosis, not its conclusion — the same code has several possible causes and the cheap one is not always right.
Common questions about U0100
Source: NHTSA files and the OBD-II standardCan I keep driving with U0100 stored?
Nobody can answer that from the code alone, and a site that does is guessing. A steady light means a fault was logged and the car should be checked soon; a flashing light means a severe misfire — slow down and get it seen as soon as possible, because severe misfire can quickly damage the catalytic converter. The safe read of this page is the mileage and the components, not permission.
Does a code mean the car is recalled?
No. Recalls are filed by campaign and matched by VIN, and none of them are triggered by a scan tool. If you want to know whether an open recall applies to one specific vehicle, check the VIN at nhtsa.gov/recalls — that is the only source that settles it.
Why do the counts here differ from other sites?
Because these are not estimates. Every number on this page is a count of documents in NHTSA's own files: manufacturer communications that name the code in their filed summary, and owner complaints that name it in the narrative. We do not model, weight or extrapolate them.
Will clearing the code fix it?
Clearing turns the light off and erases the freeze-frame data a technician would have used to work out what happened. If the condition is still there the code returns, usually within a few drive cycles, and the diagnosis now starts from less information than before.