OBD-II Diagnostic Trouble Code
P2400 — EVAP Leak Detection Pump Control Circuit/Open
P2400 means the ECM detected an open or general fault in the control circuit for the EVAP leak detection pump, used on some gasoline trucks to pressurize the fuel vapor system for leak testing. The pump is not responding to commands.
Severity 2/5
Less common on commercial trucks
Service soon
Severity
Service soon
EVAP Leak Detection Pump Control Circuit/Open
Code
P2400
Category
Powertrain
Subsystem
Emissions
Truck-relevant
Less common
What this means for truckers
P2400 (EVAP Leak Detection Pump Control) — gas engine.
Before you replace parts — try this first
P2400 on the Emissions system is most often open wiring or corroded connector at the pump (often near the fuel tank) — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Usually only a check-engine light with no driveability effect. EVAP monitors will not complete.
Common causes
- CommonOpen wiring or corroded connector at the pump (often near the fuel tank) ($80–$300)
- CommonFailed leak detection pump ($150–$500)
- OccasionalBlown fuse ($20–$100)
- RareECM fault ($600–$2000)
How to fix
Check the fuse and power supply to the pump
When to use: First check
Inspect the connector for corrosion and road damage
When to use: When power is present
Command the pump on and check for operation
When to use: To test the pump
Replace the pump
When to use: When wiring is good
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P244A — Diesel Particulate Filter Differential Pressure Too Low
- → P244B — Diesel Particulate Filter Differential Pressure Too High
- → P244C — Exhaust Gas Temperature Too Low Bank 1
- → P244D — Exhaust Gas Temperature Too High Bank 1
- → P245A — EGR Cooler Bypass Control Circuit/Open
Frequently Asked Questions
Can I drive with code P2400?
P2400 is severity 2 — service this week. Not an immediate stop, but ignoring it usually compounds the problem. Most common cause for this code is a worn sensor or minor performance fault that won't strand you today but will get more expensive the longer you wait.
How much does it cost to fix P2400 on a commercial truck?
Total repair cost ranges $20–$2000 depending on the root cause. The cheapest fix is usually the first one listed below — Open wiring or corroded connector at the pump (often near the fuel tank) — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P2400 fail a DOT inspection?
Yes — P2400 is an emissions-related code, and DOT inspectors check emissions compliance. An active emissions code with a check engine light can result in an out-of-service violation under FMCSA Part 393. The truck typically can't be moved until the code is cleared. Repeated emissions violations escalate to CSA scores.
What's the difference between P2400 and related codes?
P2400 is closely related to: P244A (Diesel Particulate Filter Differential Pressure Too Low), P244B (Diesel Particulate Filter Differential Pressure Too High), P244C (Exhaust Gas Temperature Too Low Bank 1), P244D (Exhaust Gas Temperature Too High Bank 1). These codes share the same subsystem (emissions) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P2400 is set without the companions, the issue is more isolated.
How do I prevent P2400 from coming back after a repair?
For P2400 (EVAP Leak Detection Pump Control Circuit/Open), prevention centers on the emissions system. Keep up with PM on the EGR system — clean the valve at 200K miles. Use OEM-spec air filters. Don't ignore minor codes; they often escalate into bigger emissions failures.