P0455 on 2004-2010 BMW 5-Series (E60): EVAP Large Leak Causes and Fixes

What's Unique About the 2004-2010 BMW 5-Series

Unlike many vehicles that use engine vacuum to test the EVAP system, BMWs of this era (E60/E61 generation) use a specific component called a Diagnostic Module for Tank Leakage (DMTL) pump. This electric pump pressurizes the fuel system to check for leaks. The DMTL pump itself is a very common failure point on these models and is a frequent cause of P0455 and other EVAP leak codes. The pump contains a small motor that can seize or an internal diaphragm that can tear, leading to the leak code.

Symptoms You May Notice

• Check Engine Light is on.
• A noticeable fuel smell, particularly around the rear of the car or after being parked in a garage.
• A hissing noise from the gas cap area during a system self-test.
• Difficulty refueling, where the gas pump nozzle clicks off repeatedly before the tank is full (can indicate a blocked vent valve or line).
• Slightly rough idle or difficulty starting after refueling, if the purge valve is stuck open.

Most Likely Causes

1. Loose or Faulty Gas Cap 🔴 High Probability This is the most common cause for a P0455 code on any vehicle due to user error (not tightening it) or simple wear and tear of the rubber seal. Over time, the O-ring gasket becomes hard and cracked, preventing a proper seal.
   How to confirm: Remove the gas cap and inspect the rubber O-ring for cracks, brittleness, or damage. Ensure the cap is tightened until it clicks at least once. If the cap was loose, clearing the code and driving for a few days will confirm if this was the issue.
   Typical fix: Replace the gas cap with a new OEM or high-quality aftermarket equivalent. This is an inexpensive and highly recommended first step. 🎬 Watch: How to clean and service your BMW gas cap
   Est. part cost: $20-$40
2. Failed DMTL Pump 🔴 High Probability The Bosch DMTL pump is a known high-failure item on this BMW platform. It contains a small motor and a valve that can fail electrically or mechanically, causing a leak or an inability to test the system. The wiring harness connector near the pump can also corrode or chafe through, causing an electrical fault.
   How to confirm: The definitive test requires a BMW-specific scan tool (like ISTA) to command the pump to run a leak test. A mechanic can also perform a smoke test to see if the leak originates from the pump assembly. The pump is located behind the rear passenger-side wheel well liner. Some owners test for motor failure by applying 12V directly to the pump's electrical pins and listening for it to run.
   Typical fix: Replace the DMTL pump. 🎬 See this walkthrough for replacing the E60 DMTL pump It is often replaced along with its rubber mounting grommet. The pump can be purchased separately from the charcoal canister it attaches to.
   Est. part cost: $90-$200
3. Stuck-Open Fuel Tank Vent Valve (Purge Valve) 🟡 Medium Probability This solenoid valve, located in the engine bay, can get stuck open, creating a constant large leak from the EVAP system into the intake manifold. This is a common failure on many BMW models of the era.
   How to confirm: Disconnect the valve and try to blow through it. A normally-closed valve should not allow air to pass when de-energized. You can also test its resistance with a multimeter; a good valve should read between 27-29 ohms, while a bad one may be open or have incorrect resistance.
   Typical fix: Replace the fuel tank vent valve. Check for a related fuse in the engine bay fuse box before replacing.
   Est. part cost: $70-$140
4. Cracked or Disconnected EVAP Hoses ⚪ Low Probability Over time, the plastic and rubber hoses that connect the fuel tank, charcoal canister, DMTL pump, and purge valve can become brittle and crack, especially the lines near the engine or the ones exposed under the car.
   How to confirm: A visual inspection may reveal obvious cracks or disconnections. A smoke test is the most effective method, as it will force smoke out of the exact location of the leak, which can be hard to see otherwise. Pay close attention to the hose connecting the filler neck to the tank.
   Typical fix: Replace the specific cracked hose section.
   Est. part cost: $15-$50

Rare But Worth Checking

• Cracked Charcoal Canister: While the DMTL pump attached to it fails more often, the canister itself can be damaged by road debris or age, causing a large leak. A smoke test would confirm a crack in the canister body.
• Damaged Fuel Filler Neck: Corrosion or damage to the metal filler neck where the gas cap seals can prevent a proper seal, even with a new cap. A smoke test will show smoke escaping from around the gas cap area even with a new, tight cap.

Diagnosis Steps

1. Read the code with an OBD-II scanner to confirm P0455 is present. Note any other BMW-specific codes, like 2A17.
2. Inspect the gas cap. Ensure it is tightened until it clicks. Remove it and check the rubber seal for cracks or wear. If in doubt, it's an inexpensive first replacement.
3. Clear the code and drive for a few days to see if the Check Engine Light returns. The EVAP monitor runs under specific conditions (e.g., fuel level between 15-85%), so it may take time.
4. If the light returns, perform a visual inspection of all accessible EVAP hoses in the engine bay (around the purge valve) and under the car near the rear passenger wheel (around the charcoal canister and DMTL pump). Look for obvious cracks or disconnected lines.
5. The most effective next step is a professional smoke test. A shop will inject low-pressure smoke into the EVAP system's service port. Smoke will exit from the point of the leak, pinpointing the failed component (hose, DMTL pump, canister, etc.).
6. If you have access to BMW-specific diagnostic software (ISTA), you can run the DMTL tank leakage test plan. This will activate the pump and confirm if the system can hold pressure, and can help diagnose an electrical failure of the pump itself.
7. Test the purge valve in the engine bay. With the engine off, disconnect the electrical connector and the hoses. Try to blow through it; if air passes, the valve is stuck open and must be replaced.
🎬 Watch: How to test the purge valve on your BMW

Parts You'll Likely Need

• Gas Cap (OEM #16117222391) — This is the most frequent cause of P0455 and the easiest and cheapest part to replace as a first step.
  Trusted brands: Genuine BMW, Blau, CRP
  OEM price range: $30-$40
  Aftermarket price range: $15-$25
• Diagnostic Module for Tank Leakage (DMTL) Pump (OEM #16137193479) — This is a very common failure point on the E60 platform that directly causes EVAP leak codes. The original part has been superseded multiple times, indicating revisions to the design.
  Trusted brands: Bosch (OEM), Genuine BMW
  OEM price range: $150-$200
  Aftermarket price range: $90-$130
• Fuel Tank Vent Valve / Purge Valve (OEM #13907537113) — This valve can get stuck open, creating a permanent large leak. It's a common failure item in the EVAP system.
  Trusted brands: Bosch (OEM), Genuine BMW
  OEM price range: $120-$150
  Aftermarket price range: $60-$90

Related Codes That Often Appear With This One

• P0442 — P0442 indicates a small EVAP leak. You might see this code if the component causing the large leak (P0455) is just beginning to fail, creating an intermittent or smaller leak at first.
• P0456 — P0456 indicates a very small EVAP leak. Similar to P0442, it can appear alongside P0455 if the system has multiple leak points of varying sizes or a component is failing intermittently.
• 2A17 — This is a BMW-specific fault code that directly translates to 'DMTL system fault'. If you see this code alongside P0455, it strongly points to a failed DMTL pump.

Technical Service Bulletins (TSBs) & Recalls

• While no specific TSB for P0455 on the E60 was found, BMW has issued numerous service bulletins for EVAP systems and has superseded the DMTL pump part number multiple times (previous numbers include 16136764191 and 16136752551), indicating ongoing revisions to address failures.

Platform-Specific Known Issues

• DIY DMTL Pump Replacement: Owners on forums like 5series.net have documented the DIY replacement process for the DMTL pump. The job involves jacking up the rear passenger side, removing the wheel and wheel well liner, and unbolting the pump from its bracket next to the charcoal canister. It's considered a straightforward but slightly dirty job.
• Corroded DMTL Pump Wiring: In some cases, the P0455 code is not caused by the pump itself, but by the electrical harness leading to it. The wires can rub against the chassis or wheel well liner, causing them to break or corrode, which interrupts the signal to the pump.

Mechanic-Grade Diagnostic Values

• Fuel Tank Vent Valve (Purge Valve) Coil Resistance — expected: 27 - 29 Ohms. Failure: A significantly higher or lower reading, or an open circuit (infinite resistance), indicates a failed coil.
• DMTL Pump Current Draw — expected: The DME compares the electrical current consumed by the pump during a 'Reference Leak Measurement' (pumping through a calibrated orifice) versus the 'Leak Measurement' (pumping into the fuel tank system).. Failure: A significant deviation in current between the two measurements indicates either a leak in the system or a fault with the pump motor. Specific milliamp values are interpreted by the DME to set the fault.

Hidden / Shadow Codes Worth Checking

• 2A17: DMTL, system fault. This is the most common BMW-specific code that directly points to a failure in the DMTL pump or its immediate system. (see via BMW-specific scan tools like ISTA, INPA, or high-end professional scanners.)
• 2B3A, 2B3B, 2B3C, 2B3D: Additional BMW fault codes for 'DMTL diagnosis module tank leakage, system failure'. Seeing one of these strongly suggests a problem with the DMTL pump. (see via BMW-specific scan tools like ISTA, INPA, or high-end professional scanners.)

Scan Tool Commands That Help

• ISTA/DIS: Fuel tank leakage diagnostic module DMTL — This is the primary test plan to run when a P0455 or related DMTL fault is stored. It automates the entire system test, including a reference measurement and the tank system test, to confirm if a leak is present.
• ISTA/DIS: Service functions > Drive > Digital Motor Electronics > Activation, DMTL pump > Test plan — Use this manual activation path to pressurize the system for a smoke test or to listen for pump operation. This is crucial for pinpointing a leak's location after the main test plan has confirmed a fault.

Wiring & Ground Locations

• DMTL Pump Location — Behind the passenger-side rear wheel well liner, mounted to the charcoal canister.. This is the physical location for visual inspection, testing, and replacement of the most common fault component after the gas cap.
• Fuel Tank Vent (Purge) Valve Location — In the engine bay, typically mounted on or near the intake manifold.. Location for testing the purge valve solenoid, which can get stuck open and cause a large leak.
• EVAP System Fuse — In the engine bay fuse box, located on the passenger side under the windshield cowl. It is typically the second fuse in a block of five fuses within this box.. A blown fuse will cause the DMTL pump and/or purge valve to be inoperative, leading to EVAP fault codes. Always check this fuse before replacing components.

Real Owner Repair Stories

• 5series.net user 'tpaxadpom' (2009 BMW 550i (E60)) — Check Engine Light with BMW fault code 2A17 (DMTL system fault).
  ❌ Tried (didn't work) The user went straight to diagnosis, confirming the code pointed to the DMTL.
  ✅ What actually fixed it The user replaced the DMTL pump (Bosch p/n 16137193479). The repair involved jacking up the passenger rear, removing the wheel and liner, and replacing the pump attached to the charcoal canister. After replacement, the code was cleared and did not return.

"I Checked Everything" — The Actual Cause

• A common scenario is performing a smoke test and finding no leaks, only to have the P0455 code return. In many cases, the root cause was a faulty gas cap that was inadvertently tightened or corrected *before* the test was run. A professional technician's process is to test the system as-is first. If a leak is present, they then tighten the gas cap and re-test. If the system then holds pressure, the loose gas cap is confirmed as the definitive cause, preventing unnecessary parts replacement.

OEM Part Supersession History

• 16136752551, 16136764191 → 16137193479 — Component revision and improvement by the manufacturer.
  Heads up: The newest part number is the correct replacement. Some service bulletins note that when replacing the DMTL pump, the associated charcoal filter and/or dust filter should also be replaced to ensure system integrity.

Model Year Variations Within This Range

• 2004-2010: While the E60 platform received a major Life Cycle Impulse (LCI) update for the 2008 model year which changed engines, iDrive systems, and lighting, the fundamental EVAP system design using a Bosch DMTL pump remained consistent. The primary components and diagnostic procedures for a P0455 code are the same across the entire generation.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Oil Leaks (Valve Cover Gasket, Oil Filter Housing Gasket) 🔴 High — Extremely common on all engines (N52, N54, N62) after 60,000-80,000 miles. Gaskets become brittle and leak oil onto hot engine components.
• Electric Water Pump & Thermostat Failure 🔴 High — Common on 6-cylinder (N52, N54) engines, often failing without warning between 60,000 and 100,000 miles, which can lead to rapid overheating.
• N54 High-Pressure Fuel Pump (HPFP) Failure 🔴 High — A notorious issue on the twin-turbo N54 engine (535i models). Symptoms include long cranks, reduced power, and limp mode. Subject to a warranty extension. (Ref: NHTSA Action Number: DP10005 (Warranty Extension))
• N54 Turbocharger Wastegate Rattle / Failure 🔴 High — Very common on the N54 engine (535i). Caused by wear in the wastegate actuator rod, leading to a rattling noise on deceleration and eventual loss of boost. (Ref: Warranty extended by BMW for this issue.)
• N62 V8 Valve Stem Seal Failure 🔴 High — Common on V8 models (545i, 550i) after 80,000 miles. Worn seals allow oil into the combustion chamber, causing blue smoke from the exhaust, especially after idling.
• iDrive CCC (Car Communication Computer) Failure 🟠 Medium — Affects pre-LCI models (2004-2007). The unit fails, causing a blank screen, constant rebooting, or draining the battery. Can sometimes be fixed with a hard reset.
• Taillight Connector / Positive Battery Cable Recall 🟠 Medium — Affects most E60 models. A poor connection at the positive battery cable in the trunk can cause overheating and a fire risk. A separate recall addresses taillight connector resistance causing light failure. (Ref: NHTSA Recalls: 12V126000, 12V073000)

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: Used parts are generally not recommended for this repair, as the primary failure points are wear-and-tear items. However, if a structural component like the fuel filler neck is damaged, a rust-free used part from a donor car is a viable option. The charcoal canister body could also be sourced used if it is thoroughly inspected for cracks.

Donor-vehicle mileage cap: roughly under 50000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a filler neck, inspect the gas cap sealing surface for any rust, pitting, or deformation.
• For a charcoal canister, check the plastic housing for any visible cracks, especially around the hose connections and mounting points.

OEM-only on this vehicle (don't cheap out):

• Diagnostic Module for Tank Leakage (DMTL) Pump
• Fuel Tank Vent Valve (Purge Valve)

Aftermarket brands forum-validated for this vehicle:

• Bosch is the Original Equipment Manufacturer (OEM) for both the DMTL pump and the purge valve. Choosing Bosch is equivalent to getting the Genuine BMW part without the dealer markup.

Brands owners have reported issues with on this vehicle:

• No-name, unbranded electronic parts from online marketplaces should be avoided. The EVAP system is sensitive, and an out-of-spec pump or valve can fail to fix the code or cause new, different codes to appear.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• 2A17 — A BMW-specific fault code that often appears alongside P0455, specifically relating to the DMTL system diagnostic.
• P0442 — A related EVAP code indicating a small leak; often caused by the same components as P0455 (large leak) such as a failing gas cap seal or DMTL pump grommet.
• P0171 — A lean condition code that can be triggered if the fuel tank vent valve (purge valve) is stuck open, allowing unmetered air/vapors into the intake manifold.
• P0174 — A lean condition code for bank 2 that may accompany EVAP leaks or stuck-open purge valves on BMW engines.

Frequently Asked Questions