P240D: Alternative Fuel Low Pressure System Leak

What it means

The control module detects a leak in the alternative-fuel low-pressure system. This code concerns alternative-fuel equipment; it is not a brake-hydraulic fault.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

An alternative-fuel low-pressure system carries fuel from its supply toward the higher-pressure equipment. The control module monitors this part of the system and sets P240D when it detects a leak in the low-pressure side. The code points to alternative-fuel equipment, not a brake-hydraulic leak.

Common causes

Most likely first.

1. Leaking hose or fitting
2. Damaged seal or connection
3. Cracked or damaged fuel-system component

Symptoms

• Check engine light on

How to diagnose it

1. Review freeze-frame data and any available low-pressure fuel readings to understand when the leak was detected.
2. With the vehicle safely parked and the alternative-fuel system handled according to its manufacturer's instructions, look for visible leakage around low-pressure hoses, fittings, and connections.
3. Inspect hose routing and fuel-system components for cracks, damage, or loose connections without disturbing pressurized fittings.
4. Have the low-pressure circuit leak-tested using the manufacturer's procedure to locate a leak that is not visible.
5. After repair, verify the low-pressure system holds as specified and confirm the code does not return.

Common fixes

• Replace a leaking low-pressure hose.
• Reseal or replace a leaking fitting or connection using the specified parts and procedure.
• Replace a damaged seal.
• Replace a cracked low-pressure fuel-system component.

Can I keep driving?

Do not continue driving if you smell or see alternative fuel leaking; stop in a safe place and follow the vehicle's fuel-system safety instructions. A leak can worsen and create a fire or exposure hazard, so have the system inspected before driving again.