Evaporative Emission System Leak Detection Pump Control Relay
There’s a problem with the leak detection pump control relay in the evaporative emissions system.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The car's computer tries to turn on a pump that checks for leaks in the fuel system, but it can't because something's wrong with the relay controlling that pump.
What the computer is actually seeing
The Engine Control Module (ECM) expects a specific voltage (usually around 12V) from the control relay for the evaporative emission system's leak detection pump. If it gets less than 9V when it should be powered, it triggers this code.
What a healthy reading looks like
Relay should energize and show approximately 12V at the pump side when activated, with a resistance of less than 5 ohms across relay contacts.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the vehicle's fuse box for a blown fuse related to the evaporative emissions system. Replace if necessary.
- 22. Inspect the wiring and connectors leading to the leak detection pump and relay for any signs of damage, corrosion, or loose connections. Repair as needed.
- 33. Test the relay by applying battery voltage directly to its terminals to see if it activates the pump. If not, replace the relay.
- 44. With the relay connected and activated, measure the voltage at the pump's connector. If voltage is below 9V, troubleshoot further back along the circuit.
- 55. If the pump is not running with 12V applied directly, it's likely faulty and should be replaced.
Common causes
- Faulty leak detection pump
- Defective control relay
- Wiring issue or corroded connector
- Blown fuse for the pump circuit
- ECM malfunction
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code active?
You can drive the vehicle, but emissions may be affected, and the check engine light will remain on.
Will this code come back after clearing?
If the underlying issue isn't fixed, the code is likely to return after some driving cycles.
Why does it pair with other codes?
Codes related to the evaporative system often trigger together when there’s a common issue, such as leaks or electrical failures.
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