Evaporative Emission System Leak Detection Pump Control Circuit Open
There's a problem with the control circuit for the vapor leak detection pump.
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 computer is trying to turn on a pump that checks for leaks in the gas tank, but it can't because the signal isn't getting through.
What the computer is actually seeing
The Engine Control Module (ECM) expects a voltage signal between 0.5V and 4.5V to control the vapor leak detection pump. If it sees an open circuit (no voltage), it triggers this fault.
What a healthy reading looks like
Control circuit should show 0.5V to 4.5V when the pump is supposed to be activated; otherwise, it reads open (0V).
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. Inspect wiring and connectors for the leak detection pump. Look for frays, corrosion, or damage.
- 22. Check the connector at the pump. Unplug it and inspect for bent pins or corrosion.
- 33. Measure the voltage at the connector with the ignition on. You should see a voltage between 0.5V and 4.5V.
- 44. If voltage is present, the pump is likely faulty. Test or replace the pump as needed.
- 55. If there's no voltage, trace the circuit back to the ECM and check for continuity and shorts.
Common causes
- Damaged wiring in the pump circuit
- Faulty evap leak detection pump
- Bad connector or corrosion
- Short circuits elsewhere in the evap system
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but address it soon as it can affect emissions.
Will the code come back after clearing it?
If the underlying issue isn't fixed, yes.
Why does this code appear with other evap codes?
It's often related to the same system components; check the entire evap system.
Working a real vehicle right now?
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