What causes fault code P026F?

• Most likely: Air pockets in the cooling system (pump cavitation) • Likely: Faulty electric charge air cooler pump (mechanical or internal electronic failure) • Possible: Restriction in the coolant flow path (clogged intercooler or hoses) • Rare: Wiring harness issues or corrosion in the pump connector

Powertrain (Engine & Gearbox)Standard EOBD

P026F - Charge Air Cooler Coolant Pump Performance

Q: What are the symptoms of fault code P026F?

• Check engine light (MIL) illuminated • Reduced engine performance due to high Intake Air Temperatures (IAT) • Engine may enter Limp Home mode • Unusual noise from the electric pump area if cavitating

Q: How do you fix fault code P026F?

STEP 1: Verify coolant level in the charge air cooler reservoir (often separate from the main engine cooling system). STEP 2: Use a scan tool to perform a coolant bleed procedure to remove air pockets (cavitation). STEP 3: Check power supply at the pump connector (expect 12V-14V) and inspect the PWM control signal with an oscilloscope. STEP 4: Inspect the pump ground connection (resistance should be <0.5 Ohm). STEP 5: If electrical signals are within spec and air is bled, replace the electric CAC pump.

Last updated:1 February 2026

Related:Electric Charge Air Cooler Pump (CAC Pump), IAT-sensor (Intake Air Temperature), Engine Control Unit (ECU), Coolant

System

Powertrain (Engine & Gearbox)

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Technical Description

P026F is an OBD-II diagnostic trouble code that occurs when the Engine Control Unit (ECU) detects a performance problem with the electric Charge Air Cooler (CAC) coolant pump. Many modern turbocharged or supercharged engines use a liquid-to-air intercooler system with an independent electric pump. The ECU monitors the pump's performance via PWM feedback or current draw. If the pump fails to maintain the commanded flow rate or if the cooling efficiency falls below a calibrated threshold, the code is stored. This failure can trigger Limp Mode to protect the engine from high Intake Air Temperatures (IAT) which could cause pre-ignition/knock.

Possible Causes

Air pockets in the cooling system (pump cavitation)

Faulty electric charge air cooler pump (mechanical or internal electronic failure)

Restriction in the coolant flow path (clogged intercooler or hoses)

Wiring harness issues or corrosion in the pump connector

Symptoms

Check engine light (MIL) illuminated

Reduced engine performance due to high Intake Air Temperatures (IAT)

Engine may enter Limp Home mode

Unusual noise from the electric pump area if cavitating

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P026F - Charge Air Cooler Coolant Pump Performance

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P026F - Charge Air Cooler Coolant Pump Performance

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