U1346 on 2020-2022 Chevrolet Corvette: MAF Sensor Communication Failure Causes and Fixes

What's Unique About the 2020-2022 Chevrolet CORVETTE

General Motors has issued specific Technical Service Bulletins (TSBs) for the 2020-2022 Corvette that directly address code U1346 appearing alongside MAF sensor codes P0101 and U060F. [⭐ MANUFACTURER TSB — highest authority] This indicates a known issue on the C8 platform. While the Corvette TSBs were for information gathering, a similar TSB for other GM vehicles (22-NA-008) points to a specific design flaw: a wiring harness zip tie being too tight, causing wires to break from engine movement—a highly probable cause on the Corvette as well. Forum discussions for platform-mate trucks confirm this wiring harness issue is common, often caused by the harness being too short and chafing as the engine moves.

Diagnostic Flowchart

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

Symptoms You May Notice

• Service Engine Soon (SES) or Check Engine Light illuminated on the Driver Information Center (DIC). [⭐ MANUFACTURER TSB — highest authority]
• "Reduced Engine Power" message displayed on the DIC.
• In rare, more severe cases, a no-start condition where the engine will not crank.

Most Likely Causes

1. Broken or Chafed MAF Sensor Wiring Harness 🔴 High Probability → Shop Fuel Injection Air Flow Meter TSB 22-NA-008 for other GM models identifies an overly-tightened zip tie at a harness retainer, causing a wire to break from engine flex during acceleration. This is the most likely cause. Forum discussions for GM trucks with the same codes corroborate this, with one owner reporting their shop found the harness was made 4-6 inches too short, causing it to chafe and break.
   How to confirm: With the engine running, carefully wiggle the wiring harness leading to the MAF sensor. TSB 22-NA-008 specifically suggests inspecting the 2nd retainer back from the MAF sensor and pulling on the harness to induce the fault. If this causes the engine to stumble or the code to appear/disappear, a wiring fault is present. A visual inspection may also reveal chafed insulation or a broken wire.
   Typical fix: Repair the broken wire(s) using proper wire-to-wire repair techniques. In many cases, replacing the MAF sensor pigtail connector is the recommended and most robust repair. TSB 22-NA-008 recommends using a pigtail kit for the repair.
   Est. part cost: $20-$80 for a pigtail connector or wiring repair supplies.
2. Poor Connection at MAF Sensor or ECM 🟡 Medium Probability → Shop Fuel Injection Air Flow Meter
   How to confirm: Unplug the connectors at both the MAF sensor and the ECM (if accessible). Inspect for any corrosion, moisture, or backed-out/damaged pins. Apply a small amount of dielectric grease and ensure a secure connection.
   Typical fix: Clean the connector pins and terminals. If pins are damaged, the connector may need to be replaced.
   Est. part cost: $0-$50
3. Faulty Mass Air Flow (MAF) Sensor ⚪ Low Probability → Shop Fuel Injection Air Flow Meter
   How to confirm: This should only be considered after the wiring and connections have been proven to be good. The only definitive test is to substitute a known-good MAF sensor.
   Typical fix: Replace the Mass Air Flow sensor. The OEM part for the C8 Corvette is likely GM part number 12711405.
   Est. part cost: $100-$250

Rare But Worth Checking

• Faulty Engine Control Module (ECM): → Shop Engine Control Module (ECM) This is extremely rare. The ECM should only be suspected if all wiring and sensor diagnostics have been exhaustively performed by a qualified technician.

Diagnosis Steps

1. Read all Diagnostic Trouble Codes (DTCs) from all modules using an OBD-II scanner.
2. Note the presence of U1346 along with P0101 and/or U060F, which strongly indicates a MAF sensor circuit issue. [⭐ MANUFACTURER TSB — highest authority]
3. Perform a careful visual inspection of the entire wiring harness leading to the Mass Air Flow sensor. Look for signs of chafing, rubbing against other components, or sharp bends near harness retainers.
4. With the engine idling, gently wiggle and pull on the MAF sensor harness at various points, paying special attention to the area near the second harness retainer from the sensor, as per TSB 22-NA-008. If the engine stumbles or stalls, you have likely found the location of the intermittent break.
5. If wiggling does not produce a result, disconnect the MAF sensor and inspect the connector terminals for corrosion or damage.
6. Using a digital multimeter and the vehicle's wiring diagram, check for proper voltage, ground, and signal continuity on the wires between the ECM and the MAF sensor connector.
7. If wiring and connections are confirmed to be 100% intact, suspect a faulty MAF sensor.
8. Clear all DTCs and perform a test drive to confirm the repair.

Parts You'll Likely Need

• MAF Sensor Pigtail Connector (OEM #85519071) — If the wire is broken at the connector, replacing the pigtail is the most robust repair. This part number is specifically recommended in TSB 22-NA-008 for this issue.
  Trusted brands: ACDelco, Dorman
  OEM price range: $40-$80
  Aftermarket price range: $20-$40
• Mass Air Flow (MAF) Sensor (OEM #12711405) — This is replaced only after confirming the wiring is not at fault. It is a common misdiagnosis. The part number 12671624, previously associated with this code, appears to be for other GM vehicles, not the C8 Corvette.
  Trusted brands: ACDelco
  OEM price range: $100-$200
  Aftermarket price range: $80-$150

Related Codes That Often Appear With This One

• P0101 — This code for 'Mass Airflow Sensor Performance' is often set because the communication loss from the U1346 fault causes the ECM to receive irrational data from the sensor.
🎬 See this simple explanation of P0101 symptoms and common causes.
• U060F — This code for 'Lost Communication with Mass Airflow Sensor 1' is a more direct statement of the same network fault and is frequently logged alongside U1346, as noted in TSB PIE0681A. [⭐ MANUFACTURER TSB — highest authority, 12]

Technical Service Bulletins (TSBs) & Recalls

• PIE0681A: Engineering Information – Service Engine Soon Lamp Illuminated on Driver Information Center (DIC), Diagnostic Trouble Codes (DTC) P0101, U060F and/or U1346 Set. [⭐ MANUFACTURER TSB — highest authority]
• PIE0681: An earlier version of the same bulletin. [⭐ MANUFACTURER TSB — highest authority]
• 22-NA-008: A related TSB for other GM models (Buick Encore GX, Chevy Trailblazer) that identifies a broken wire in the MAF sensor harness due to an over-tightened zip tie as the cause for the same set of DTCs.

Platform-Specific Known Issues

• GM issued Technical Service Bulletin #PIE0681A specifically for the 2020-2022 Corvette, acknowledging an issue where codes P0101, U060F, and/or U1346 may be set, triggering the Service Engine Soon lamp. [⭐ MANUFACTURER TSB — highest authority]
• The bulletin for convertible models specifically asks technicians to note the position of the top when the fault occurred, suggesting a link to harness flexing or movement.
• While the Corvette TSB is for information gathering, TSB 22-NA-008 for other GM vehicles provides the likely root cause: a broken wire at a zip-tied harness retainer, caused by engine movement.

Mechanic-Grade Diagnostic Values

• Mass Air Flow Rate at Warm Idle (Scan Tool PID) — expected: ~6.2 grams/second (g/s). Failure: Readings significantly higher or lower than the engine's displacement in liters, or readings that are erratic.
• MAF Sensor Signal Voltage (at ECM) — expected: 0-5V varying with airflow. Failure: No voltage, or voltage that is stuck high or low and does not respond to changes in engine RPM.

Wiring & Ground Locations

• ECM Connector X1, Pin 37 — At the Engine Control Module (E99 ECM).. This is the specific pin for the MAF Sensor Signal (Circuit 492). A technician can perform a continuity test from this pin to the MAF sensor connector to verify the integrity of the signal wire that is known to break.
• Engine Harness Chafe Points — Inspect the entire MAF harness, especially near retainers/zip ties and where it may contact other components. A harness has been observed resting on the lower control arm on some C8s, creating a potential chafe point.. Engine movement can cause the harness to rub against chassis or engine components, wearing through the insulation and causing a short or open circuit, which is the primary cause of this code.

Real Owner Repair Stories

• Reddit user onlyAnotherHalfMile in r/Silverado (2019 Silverado 1500 5.3L with 98k miles) — Check Engine Light with code U1346.
  ❌ Tried (didn't work) The owner did not list things that didn't work, but took it to a shop for diagnosis.
  ✅ What actually fixed it A repair shop confirmed the wiring harness was 'all chafed up' and performed a repair. The shop noted that GM had made the harness 4-6 inches too short, causing it to rub and break as the engine moves. The repair took two full days and cost $600.

OEM Part Supersession History

• 12671620, 12714359, 12714453 → 12711405 — Standard part evolution and consolidation by the manufacturer.
  Heads up: Part 12711405 is the current recommended OEM part for the C8 Corvette 6.2L engine.
• 22895480, 23144941 → 23262344 — Standard part evolution. This part number is associated with the C7 generation but may be found on very early 2020 models.
  Heads up: While for the previous generation, it's a relevant part number in the history of the LT engine family.