2007 Toyota Prius BaseFACTORY OEM SERVICE PROCEDURE

DTC P2601 Coolant Pump Control Circuit Range / Performance: Description

The coolant heat storage system uses an electric pump to supply hot coolant stored in the CHS tank into the cylinder head of the engine, in order to optimize engine starting combustion and reduce the amount of unburned gas that is discharged while the engine is started. Before the engine starts, the ECM operates the electric water pump to direct the hot coolant in the CHS tank into the engine, in order to heat the cylinder head (this process is called "preheat mode"). This system consists of the CHS tank, CHS water pump, CHS tank outlet temperature sensor, water valve, and a soak timer that is built in the ECM.

DTC DETECTION CONDITION

DTC No. DTC Detection Condition Trouble Area
P2601 Following conditions are successively met:
  • Difference in CHS tank outlet water temperature and engine coolant temperatures before and after starting preheating: within 2Β°C (3.6Β°F)
  • Change in CHS tank outlet water temperature during soaking: Below 1Β°C (1.8Β°F) of its temperature before CHS water pump is ON
  • CHS water pump
  • CHS water pump relay
  • Open or short in CHS water pump circuit
  • ECM
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.