P248E: EGR Cooler Bypass Control Circuit/Open (Bank 2)

P248E is the bank 2 counterpart of P245A: the engine controller sees no proper load on the output that drives the EGR cooler bypass of the second cylinder bank, most often because the circuit is open. Only engines with a separate EGR path per bank can set it, which in practice means V engines with two coolers. No manufacturer documents this code publicly; the published diesel tables we checked only list bank 1. For comparison, GM's 2017 Duramax tables flag the bank 1 DC-motor flap when the load resistance with the H-bridge switched off exceeds 200 kOhm, rated Type B. CARB requires such actuators to be checked as comprehensive components. With the flap unpowered, warm-up or cooling of the recirculated gas is no longer controlled on that bank.

Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.

Symptoms

• Check engine light on
• Longer warm-up or higher NOx on one bank because the bypass stays put

Most likely causes

• Unplugged connector or broken wire at the bank 2 bypass actuator
• Open motor or solenoid winding in the bank 2 actuator
• Faulty output stage in the engine control module

What to check, in order

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

1. Check the connector and any vacuum hoses
2. Check the continuity of the wire between the component and the control module.
3. Use live data to compare the commanded opening with the actual opening
4. Clean the valve and passages if they are clogged with carbon
5. Test the actuator with the scanner
6. 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 P248E means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• 4: Emissions
• 8E: Specific fault in that system

Frequently asked questions

Can I keep driving with code P248E?

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 P248E?

The most common causes are: unplugged connector or broken wire at the bank 2 bypass actuator; open motor or solenoid winding in the bank 2 actuator; faulty output stage in the engine control module.

Related codes

• P245AEGR Cooler Bypass Control Circuit/Open (Bank 1)
• P248FEGR Cooler Bypass Control Circuit Range/Performance (Bank 2)
• P2490EGR Cooler Bypass Control Circuit Low (Bank 2)
• P2491EGR Cooler Bypass Control Circuit High (Bank 2)
• P24A6EGR Cooler Bypass Control Stuck/Open (Bank 2)

Sources

• law.cornell.edu: 13 CCR 1968.2
• gsi.ext.gm.com: 17OBDG04 Engine Diagnostics

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.