P26B4 on Toyota: How to Diagnose & Fix
Charge Air Cooler Coolant Pump Performance
1 Toyota model · 1 documented issue · $100-$2,000 repair
P26B4 on Toyota by model: symptoms, diagnosis and fix
The 2023+ Sequoia with the i-FORCE MAX twin-turbo V6 hybrid powertrain has experienced cooling system issues related to the added complexity of cooling both the twin-turbo engine and hybrid battery system. Owners report coolant loss with no visible external leak (internal leak at turbo coolant lines), electric cooling fan running continuously at high speed even in mild weather, and occasional overheating warnings during towing. The hybrid battery cooling circuit is separate from the engine cooling circuit and has its own failure modes.
Common Symptoms
- Coolant level dropping with no visible leak
- Cooling fans running at high speed constantly
- Overheating warning while towing
- Sweet coolant smell from engine bay
- Hybrid system reduced power warning
- Engine temperature gauge reading higher than normal
How to Fix
For coolant loss: have the dealer pressure test both the engine and turbo cooling circuits. Common leak points are the turbo coolant feed/return lines and the intercooler. For continuous fan operation: the hybrid battery cooling fans have an independent control module — check for DTCs related to battery temperature management. For towing overheating: ensure the transmission cooler and auxiliary cooler (if equipped with tow package) are functioning. Toyota has issued TSBs addressing cooling system software calibration. Verify all cooling system software is at the latest version.
Owner tips & cautions
- WarningCheck coolant level weekly during the first year of ownership. The twin-turbo system has many more coolant connections than a naturally aspirated engine. Catching a small leak early prevents overheating damage.
P26B4 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P26B4 mean on a Toyota?
P26B4 stands for "Charge Air Cooler Coolant Pump Performance." P26B4 is a powertrain code relating to the charge air cooler (intercooler) coolant pump performance on a liquid-cooled intercooler system, where an electric pump circulates coolant to cool the pressurized intake air from the turbocharger. The computer commands the pump and monitors flow, speed, or current, and sets this code when the pump's performance is outside the expected range. This can lead to higher intake air temperatures, reduced boost or power, and possible knock protection. It points to the charge-air-cooler coolant pump or its loop rather than the main engine cooling system. On Toyota it is documented across 1 model: Sequoia.
What are the most common causes of P26B4?
The most common causes of P26B4 are: Failed or weak charge air cooler coolant pump, Low coolant or air pocket in the intercooler loop, Coolant leak in the charge air cooler circuit, Clogged or restricted intercooler coolant passages, Wiring, connector, fuse, or relay fault at the pump, Faulty coolant temperature or flow sensor in the loop, PWM control or driver fault in the controlling module. The specific cause varies by vehicle.
How much does it cost to fix P26B4 on a Toyota?
Published repair estimates on Toyota range from $100 to $2,000 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P26B4 on a different make?
View P26B4 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.