P26CA: Engine Coolant Pump Control Circuit/Open

Many engines replace the belt-driven water pump with an electric pump that has its own control electronics. P26CA flags a fault in the control connection to that pump. In the Ford 2.0 L hybrid system the pump is commanded over LIN and also has a backup run line wired to ignition; the PCM compares the state of this line reported by the pump with the real ignition state and sets P26CA after five seconds of mismatch. Toyota applies it to A25A engines (Camry, RAV4, Highlander, Sienna and Venza, 2020–2024) use the code with suffixes for a grounded or broken circuit and for a missing signal, in some cases with coolant leaking from the pump into its connector. Ford service messages 46857 and 47790 trace it to water in harness connectors. The pump may run on a fallback speed or stop.

Symptoms

• Check engine lamp on
• Rising coolant temperature or temperature warning
• Coolant traces at the electric pump

Most likely causes

• Water or corrosion in the pump connector or harness connectors
• Coolant leaking from the pump body into its electronics
• Broken control or backup run wire between module and pump

What to check, in order

Start with the simplest. You can tick off each step.

1. With the engine cold, check the coolant level; never do this when the system is hot
2. Check the continuity of the wire between the component and the control module.
3. Check the actual temperature in live data
4. Make sure the fan comes on when it should
5. Check the thermostat and connector
6. Measure the sensor and replace it if its readings do not make sense

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P26CA means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 6: Control modules and outputs
• CA: Specific fault in that system

Frequently asked questions

Can I keep driving with code P26CA?

Watch the temperature gauge. If it climbs or a warning appears, stop the car in a safe place and turn off the engine: overheating can cause serious damage.

What causes code P26CA?

The most common causes are: water or corrosion in the pump connector or harness connectors; coolant leaking from the pump body into its electronics; broken control or backup run wire between module and pump.

Related codes

• P26CBEngine Coolant Pump Performance/Stuck Off
• P26CCEngine Coolant Pump Control Circuit Low
• P26CDEngine Coolant Pump Control Circuit High
• P26D3Engine Coolant Pump Supply Voltage Circuit
• U019FLost Communication With Engine Coolant Pump Control Module

Sources

• fordservicecontent.com: OBDSM1901 HEV
• static.nhtsa.gov: MC 10236209 9999
• static.nhtsa.gov: MC 10155562 9999
• static.nhtsa.gov: MC 10125076 9999

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.