Chevy Code U062F: Meaning, Causes & How to Fix It

Before anything else: the definition almost every site gives for U062F belongs to a different code. "Control Module Long Term Memory Performance," the EEPROM fault, is P062F — a P-code, not a U-code. They differ by one character and they are not the same fault. We went looking for GM's own descriptor for U062F and could not find one in any primary source. What we did find is a single GM bulletin that names the code, and in that document it has nothing to do with module memory at all.

What U062F Actually Is

The U0xxx range is GM's network communication family — codes about modules failing to exchange data, not about a component failing. So U062F is a network code by its position in the numbering scheme. That much is structural and safe to say.

Beyond that, we will not pretend to more certainty than the evidence supports. We could not locate GM's published descriptor for U062F in any manufacturer source. GM Service Information is behind a paywall, and none of the GM bulletins filed publicly with NHTSA that mention this code define it. If you have a scan tool in front of you, the text it displays alongside the code is better evidence than anything published about U062F online, including this page.

What we can tell you with confidence is where GM does mention it, and what GM says the cause was in that context. That is below.

First, Check Whether You Actually Have P062F

This matters more than anything else on the page, because the two codes send you in completely different directions.

Scan tools and code readers routinely transpose the leading character, and the two codes look nearly identical in a photo of a screen. If your tool showed "062F" and you are not certain of the prefix, re-read it before buying anything. Everything written online about "U062F meaning EEPROM or long term memory" is describing P062F.

The One GM Document That Names U062F

GM bulletin 21-NA-149, "Engine Wire Harness Chafing," is the only GM document we located containing the string U062F. It appears there in a list of codes, with no definition attached, and the context is specific:

• Condition 3 of the bulletin, and the 3.0L Duramax (LM2) only.
• Vehicles: 2019–2023 Chevrolet Silverado 1500, Suburban and Tahoe, plus the GMC and Cadillac equivalents.
• The cause GM documents is a chafed engine wire harness — specifically at harness grid coordinates G-8 and C-9. Not a module fault, not a memory fault, not a failed component.

If you have a 3.0L diesel Silverado, Tahoe or Suburban from that range and U062F has appeared, that bulletin is where to start, and the repair is wire and tape rather than a module.

One caution GM attaches: check the VIN against Customer Satisfaction Program N192219370 before proceeding, because some VINs are excluded from this bulletin's coverage.

The Two-Part Code Form: U062F-XX

GM does publish codes in two-part form — we have confirmed GM writing codes such as U0422 00 in its own bulletins, and GM defines failure byte 71 as "Invalid Data" across all GM models from 2013 to 2022. So the scheme is real.

But no GM-documented sub-types were found for U062F specifically. The one bulletin naming this code lists it bare, without a failure type byte.

The 32-row sub-type tables published for this code on several sites run -00 through -1F with distinct meanings. That ladder is generated automatically for every code on those sites. It carries no manufacturer attribution and it is not GM data.

Symptoms

We are not going to list owner symptoms for U062F, because we could not source any to GM for this code, and inventing a plausible-sounding list is exactly what we are trying to correct here.

What we can report is the symptom set GM documents for 21-NA-149, the bulletin U062F appears in — these are the complaints that bring a 3.0L Duramax in with a chafed harness:

• Check engine light or service engine soon light on
• No start, or no crank
• Engine runs rough
• Reduced engine power
• Erratic speedometer
• Instrument cluster gauge sweep
• Blown fuses
• Stalling

The pattern to notice is that a chafed harness produces scattered, unrelated faults. If U062F arrived alongside a spread of things that seem to have nothing to do with each other, that is the signature.

How It's Diagnosed

You need a scan tool that reads all modules and shows the full code description — GDS2 or Techline Connect on GM platforms, or a professional aftermarket tool with GM enhanced coverage. A generic OBD-II reader will show you "U062F" and no context, which on this particular code is worse than useless given how much bad information exists about it.

1. Confirm the prefix. U062F or P062F. This determines everything that follows.
2. Read the full description your tool displays alongside the code, and note which module reported it. That text is your most reliable evidence of what the code means on your specific vehicle.
3. Run the Diagnostic System Check — Vehicle and record every code in every module, not just this one.
4. If the vehicle is a 2019–2023 Silverado 1500, Tahoe or Suburban with the 3.0L LM2 diesel, inspect the engine harness for chafing per 21-NA-149, paying attention to grid coordinates G-8 and C-9.
5. Check the VIN against Customer Satisfaction Program N192219370 for exclusions.
6. Treat any scattered, apparently unrelated codes as evidence for a harness or ground fault rather than several separate component failures.

Parts and Labor

There is no "U062F part." No GM control module part number is associated with this code in any source we could verify. In the one context GM documents, the repair is harness protection.

That is the whole verified parts list for this code: tape, sleeves, clips and tie straps. Anyone quoting you a control module against U062F alone should be asked what evidence points at the module.

What Other U062F Pages Get Wrong

This code has an unusually poor information footprint, and the errors are not small ones:

• "U062F is Control Module Long Term Memory Performance." That is P062F. Different family, different fault, different repair. This is the single most-repeated error about this code.
• "U062F is Lost Communication With Coolant Pump C." This circulates on aggregator sites and forums. We could not attribute it to any GM source, so we flag it as unverified rather than repeating it as fact.
• The 32-row sub-type table. Auto-generated boilerplate, applied identically to every code on the sites that publish it.
• Confident cause lists and symptom lists. Several pages give ranked causes and detailed owner symptoms for U062F. None that we checked cited a source, and GM's one bulletin naming the code attributes it to a chafed harness on one specific engine.

For context on how unreliable searching is for these codes: of 28 NHTSA bulletin PDFs that surfaced in searches for this group of codes, only 6 actually contained the code that surfaced them. Titles cannot be trusted; the document has to be opened.

Frequently Asked Questions

Is U062F the same as P062F?

No. They differ by the first character and they are different faults. P062F is a powertrain code documented by GM as control module long term memory performance — the EEPROM fault — and GM's remedy is to identify the setting module and reprogram it. U062F is in GM's network communication range. Nearly everything published online describing "U062F" as an EEPROM or memory fault is actually describing P062F.

What does U062F mean exactly?

We will not invent an answer. GM's published descriptor for U062F is not available in any primary source we could reach — GM Service Information is paywalled, and the one public GM bulletin naming the code lists it without a definition. The description your scan tool displays is better evidence than anything published about this code online.

Does U062F mean I need a new control module?

There is no evidence for that. No GM control module part number is tied to this code in any source we could verify. In the only context GM documents — a 3.0L Duramax with a chafed engine harness — the repair is tape, sleeving and clips totalling a couple of hours of labor.

My 2021 Silverado 3.0L diesel has U062F. Where do I start?

GM bulletin 21-NA-149, Condition 3, which covers exactly that vehicle and engine. The documented cause is engine harness chafing at grid coordinates G-8 and C-9. Have the harness inspected there before anything is replaced, and check your VIN against Customer Satisfaction Program N192219370, because some VINs are excluded.

What does the -00 mean in U062F-00?

No GM-documented sub-types exist for U062F. The one GM bulletin naming it writes it bare. A -00 on your tool is the generic "no sub type information" value, not a specific GM-defined fault mode.

Why did U062F show up with a lot of other unrelated codes?

That is the signature of a wiring problem rather than several separate failures. A chafed harness carries many circuits, so damage to it produces scattered faults across systems that have nothing to do with each other — which is precisely why GM's bulletin lists this code alongside a long list of others.

Can I keep driving with U062F?

It depends entirely on what else is happening. If the vehicle drives normally and this is the only code, it is not urgent, though it should be diagnosed. If it came with no-start, stalling, reduced power or blown fuses — the symptom set GM documents for the bulletin this code appears in — that is a harness fault that can leave you stranded and should be looked at promptly.

Why is there so little reliable information about this code?

Partly because GM's own definition is not publicly published, and partly because the gap has been filled by automatically generated pages. Many sites produce a definition, a cause list and a 32-row sub-type table for every conceivable code whether or not any manufacturer data exists for it. When you search a rare code, that machine-generated content is often all you find.

Shop the Parts Mentioned

• KONNWEI KW850 OBD2 Scanner — $83.11, retrieves generic (P0, P2, P3, U0) and manufacturer-specific (P1, P3, U1) codes, so it reads network codes like this one. Live data with graphing, freeze frame, O2 and EVAP tests, battery voltage check, and a built-in DTC lookup library. Engine-system coverage only — it does not read ABS or airbag modules.
• VDIAGTOOL BT500 Battery Tester — $57.53, tests battery health, cranking and charging on 6V/12V/24V systems with ripple analysis and a voltage waveform — rules out low system voltage, a common trigger for spurious module-communication codes.
• ACDelco Professional Multi-Purpose Relay — a replacement relay for a failed power-feed relay on the affected module.
• ACDelco Gold Negative Battery Cable — addresses voltage instability contributing to network faults.
• 95-Piece Mechanics Tool Set (Metric & SAE) — for wiring and connector access during diagnosis.

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