If you drive a Cadillac Escalade, Chevrolet Tahoe, Suburban, Silverado 1500, GMC Yukon, or Sierra 1500, you may have already seen a Check Engine Light related to a coolant control valve problem.
Many 2021–2023 GM vehicles—especially those equipped with the 3.0L Duramax diesel (LM2 or LZ0)—have been affected by failures of the engine coolant control valve, sometimes called the engine coolant flow control valve.
This part plays a crucial role in regulating coolant flow to help the engine maintain proper operating temperature. When it fails or sticks, it can cause check-engine lights, overheating, and even high-speed radiator fan operation after the engine is turned off.
What the Issue Is
The engine coolant control valve manages how coolant circulates through the radiator and engine. When it fails, owners often report one or more of these diagnostic trouble codes (DTCs):
- P1098 – Coolant Control Valve Performance (common on 3.0L Duramax models; fans may run at high speed even after the key is off)
- P26BB / P2B60 – Coolant Flow Control Valve Position/Learn Faults
These codes can trigger the Check Engine Light (MIL) and may cause excessive fan noise or poor temperature regulation.
Vehicles Involved
GM lists the following vehicles as potentially affected:
- 2021–2023: Cadillac Escalade, Chevrolet Tahoe / Suburban, GMC Yukon / Yukon XL
- 2021–2022: Chevrolet Silverado 1500, GMC Sierra 1500
The issue is most prevalent in vehicles with the 3.0L Duramax diesel engine (LM2 or LZ0), but can appear in some gasoline variants as well.
What GM Told Dealers to Do
General Motors has released several Technical Service Bulletins (TSBs) and Preliminary Information (PI) documents to guide technicians:
- 22-NA-082 (April 2022) – Software programming update for vehicles displaying P1098 / P26BB / P2B60 codes.
- PIP5791A (January 2022) – Directs technicians to command the valve open and closed multiple times to verify function before replacement.
- Earlier PI (2019 → carried forward) – Replace the valve and perform a relearn if previous codes were logged and diagnostics confirm failure.
- 21-NA-271 (August 2023) – Advises checking for kinked cooling hoses that can cause similar fault codes before replacing the valve.
Special Coverage Program for 3.0L Duramax Models
In September 2025, GM announced a Special Coverage Program for the coolant control valve affecting certain 3.0L Duramax models.
- Coverage up to 15 years / 150,000 miles (240,000 km) from the vehicle’s in-service date
- Applies to Silverado 1500, Sierra 1500, and full-size SUVs equipped with 3.0L Duramax engines
- Covers replacement of the coolant control valve and related programming if diagnostics confirm failure.
- Program IDs: N252508340 and N252508341
What Owners Should Do
- Get the codes read – Look specifically for P1098, P26BB, or P2B60.
- Visit your GM dealer – Mention TSB 22-NA-082 and Special Coverage N252508340/N252508341.
- Ask for a diagnostic and repair under warranty coverage if applicable.
California Lemon Law: Repeated Coolant Valve Problems Could Mean Your Vehicle Is a Lemon
If your GM SUV or truck has been in the shop multiple times for the repeated issues—or has been out of service for an extended period due to repeated repairs—you may have additional protection under the California Lemon Law (formally the Song-Beverly Consumer Warranty Act).
When Lemon Law Might Apply
You may qualify if:
- The vehicle is still under the manufacturer’s warranty (including extended “special coverage” programs).
- The dealer has attempted several repairs for the same problem without success.
- The issue substantially impairs the vehicle’s use, value, or safety (for example, repeated overheating or engine cooling failure).
- The vehicle has spent a significant number of days in the shop for warranty-related repairs.
If those conditions apply, California law may require GM to repurchase or replace your vehicle.
How to Take Action
- Keep records of all service visits, repair orders, and communication with your dealer.
- Request a copy of your vehicle’s repair history and diagnostic codes.
- Consult a California Lemon Law attorney or consumer-protection advocate if your issue persists after repeated repairs.
(Tip: Lemon Law claims can often be handled at no cost to the consumer—attorney fees are typically paid by the manufacturer if you prevail.)
