P26BB on 2021-2022 Chevrolet Silverado 1500 (LT, RST, LTZ, High Country) — Engine Coolant Bypass Valve "C" Range/Performance
1 vehicles · 1 makes
Most Reported On
P26BB is an OBD-II diagnostic trouble code meaning “Engine Coolant Bypass Valve "C" Range/Performance.” A generic OBD-II code indicating engine coolant bypass valve C is electrically operating but its performance (actual coolant flow/temperature response versus expected) is out of range. On some vehicles this can appear transiently during the valve break-in period and self-clear after further actuations. This code is most commonly reported on 2021-2022 Chevrolet Silverado 1500 (LT, RST, LTZ, High Country).
Common Causes
Diagnostic Tools
This is a powertrain code, so a basic OBD-II reader can read it. These read P26BB.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple code reader for engine (P) codes on many compatible OBD-II vehicles. It does not support every vehicle or hybrid/EV application, and it does NOT read body, chassis or network codes; confirm exact-vehicle compatibility before buying.
- Read & clear engine (P) codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth scanner with a companion app that reads beyond the engine module — ABS, SRS and transmission — plus manufacturer-specific codes on many vehicles.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X V3.0 Elite OBD-II Scanner
by LAUNCH
Handheld scanner covering the four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level tablet with all-system coverage and bi-directional control, so you can command a module rather than only read it.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
What you can do yourself, and what needs a shop
Reading the code, clearing it, and watching whether it returns is a driveway job with the right scanner. These steps are not:
- Module programming or software updates — needs the manufacturer software or a J2534 pass-through with a paid subscription.
- Replacing a control module — most are VIN-programmed and immobilizer-registered, so a new one does nothing until it is coded to your car.
- Airbag/SRS component work — a stored fault can deploy a live device.
If the vehicle is still under warranty, check for an open recall or technical service bulletin before buying anything — the repair may already be covered.
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FAQ
What does P26BB mean?
P26BB stands for "Engine Coolant Bypass Valve "C" Range/Performance." A generic OBD-II code indicating engine coolant bypass valve C is electrically operating but its performance (actual coolant flow/temperature response versus expected) is out of range. On some vehicles this can appear transiently during the valve break-in period and self-clear after further actuations.
What are the most common causes of P26BB?
The most common causes of P26BB are: Coolant bypass valve C sticking or slow to respond, Debris/contamination affecting valve travel, Valve break-in variation (low mileage), Coolant flow restriction, Valve wear or internal fault, Faulty ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P26BB?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P26BB?
Au7o has documented P26BB across 1 vehicle models from 1 manufacturers: Chevrolet.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.