P2426: EGR Cooling Valve Control Circuit Low

P2426 is set when the command wire of the cooling valve reads too low, which on most driver stages means the wire is shorted to ground or the output cannot pull up. In Ford's Power Stroke summary the low and high faults are detected together by a short-circuit check of the cooler bypass actuator that runs all the time and fails after 2 seconds. Volkswagen instead applies a fixed limit to the CNRB 3.0 TDI of the 2014 Touareg: below 2.97 V on the signal the code is stored. Chafed insulation against the exhaust or the engine block is the usual cause. The bypass flap then stays in its default position, which can make the warm-up longer or the EGR gas hotter.

Medium severity. Can I keep driving?You can normally drive in moderation, but get it repaired soon: if the valve is stuck open, the engine may idle very poorly.

Symptoms

Check engine light
Bypass flap no longer moves

Most likely causes

Control wire chafed through and shorted to ground
Internal short in the valve actuator
Faulty output stage in the engine control module

What to check, in order

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

Check the connector and any vacuum hoses
With the connector unplugged, check whether the signal wire is making contact with ground.
Use live data to compare the commanded opening with the actual opening
Clean the valve and passages if they are clogged with carbon
Test the actuator with the scanner
Replace the valve if it still does not follow the command after cleaning

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P2426 means

P: Powertrain: engine and transmission
2: Generic code: same on every make
4: Emissions
26: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2426?

You can normally drive in moderation, but get it repaired soon: if the valve is stuck open, the engine may idle very poorly.

What causes code P2426?

The most common causes are: control wire chafed through and shorted to ground; internal short in the valve actuator; faulty output stage in the engine control module.

Related codes

Sources

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.