01 Transmission vs. Engine Braking: Which Method is Right for … • 02 The Hidden Safety Feature In Modern Cars That Most Owners N… • 03 P0107 and P0108: Manifold Absolute Pressure (MAP) Sensor Ci… • 04 Pros and Cons of Using a Mortgage Loan to Buy a Car: What Y… • 05 You Could Lose All Power On The Highway If This Problem Kee… • 06 How Cold Weather Affects Your Car Battery • 07 What Speed Do Planes Take Off At? Factors and Examples • 08 ENGINE NOISE DIAGNOSTICS • 09 U0009 High Speed CAN Communication Bus (-) shorted to Bus (… • 10 That Rotten Egg Smell From Your Exhaust Isn't Normal: Here'… •

DTC codes / P26xx · Computer and output circuits / P26AB

P26ABEngine Coolant Bypass Valve A Stuck/Open

P26AB means the engine computer has commanded the coolant bypass valve to move, but the valve's position feedback or the resulting temperature change indicates it is stuck or stuck open. The powertrain control module (PCM) monitors the valve's response and sets this code when the actual state does not match the commanded state within a calibrated time.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaComputer and output circuits

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage