Investigating the P0100 Code on Your 2021 GMC Yukon
A P0100 code on your 2021 GMC Yukon means the ECM has detected a mass airflow (MAF) sensor circuit malfunction. The fifth-generation Yukon is available with the 5.3L V8 (L84), 6.2L V8 (L87), or the 3.0L Duramax turbo-diesel inline-six, and all engines need accurate MAF data for proper management.
What P0100 Means
P0100 flags erratic, intermittent, or out-of-range MAF sensor signals. On the naturally aspirated V8s, the MAF feeds data for fuel injection and Dynamic Fuel Management (DFM) cylinder deactivation. On the Duramax diesel, it also informs turbo boost management and diesel emissions systems.
Common Symptoms
- Check engine light on
- Rough or unstable idle
- Reduced power (noticeable with passengers or towing)
- Poor fuel economy
- Hesitation during acceleration
- DFM irregularities (V8s)
- Duramax: possible DPF/DEF system alerts
Top Causes Ranked by Likelihood
- MAF sensor contamination (35-40%) — Dust, oil vapor, and debris on the sensing element
- Air filter issue (20-25%) — Dirty or improperly seated filter
- Intake duct leak (10-15%) — Cracked boot or loose clamp
- Connector or wiring fault (10-15%) — Corroded or loose connection
- MAF sensor failure (10-15%) — Internal degradation
Diagnostic Steps
Inspect the air filter and MAF connector. Clean the MAF with dedicated cleaner ($10-15). Check intake ducting for cracks. Use GDS2 or a compatible scan tool to compare live MAF data against specs for your engine variant.
Warranty Status
Your 2021 Yukon's basic warranty (3yr/36k) expired in 2024. The powertrain warranty (5yr/60k) runs through 2026. Federal emissions warranty covers the MAF for 8 years/80,000 miles through 2029.
Estimated Repair Costs
- MAF sensor cleaning: $10-15 (DIY)
- Air filter: $25-45
- MAF sensor replacement: $100-280 (OEM) + $80-150 (labor)
- Intake duct: $40-100 + $60-100 (labor)