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DTC codes / BMW codes / P1449

P1449 · BMWDiagnostic Module Tank Leakage DM-TL Pump Too High

P1449 on BMW vehicles indicates that the Diagnostic Module Tank Leakage (DM-TL) pump is reporting a signal that is too high, meaning the pump's electrical circuit is drawing excessive current or the pump itself is failing. The engine control module detects this out-of-range condition during its evaporative emission system self-test and stores the fault.

SystemPowertrain
Code typeBMW specific
SeverityLow
Fix difficultyIntermediate
AreaAuxiliary emission controls

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • A faint fuel odor may be present if the pump has failed and the tank cannot be properly sealed.
  • Rough idle or slight hesitation in rare cases where the pump fault affects purge flow.
  • The DM-TL pump may run continuously or not at all, which can be heard as an unusual humming from the rear of the vehicle.
  • In some instances, the vehicle may fail an emissions inspection due to the stored fault.

Common causes, most likely first

  1. Faulty DM-TL pump (leak detection pump) drawing too much current.
  2. Corroded or damaged electrical connector at the DM-TL pump.
  3. Chafed or shorted wiring in the pump circuit, causing high current draw.
  4. Failed engine control module (ECM) driver for the pump circuit, though rare.
  5. Blocked or kinked evaporative emission hose causing the pump to work harder and draw excess current.
  6. Internal failure of the pump's motor or solenoid.

How to diagnose and fix it

  1. Perform a visual inspection of the DM-TL pump, its connector, and wiring for corrosion, damage, or loose pins.
  2. Use a scan tool to command the DM-TL pump on and off while listening for operation and checking for unusual noises.
  3. Measure the current draw of the pump with a clamp meter; compare to BMW specifications (typically under 1 amp).
  4. Check the evaporative emission hoses for blockages or kinks that could overload the pump.
  5. If current draw is excessive, replace the DM-TL pump after confirming good wiring and connections.
  6. Clear the fault codes and drive the vehicle through a complete evaporative system monitor to verify the repair.
  7. If the fault persists, check the ECM driver circuit for shorts to power or ground, and repair as needed.

Don't overlook the simple electrical checks

  • A corroded connector at the DM-TL pump is a common cause of high current draw that is often misdiagnosed as a failed pump.
  • The DM-TL pump only runs during specific conditions, so a fault may not set immediately; a full drive cycle is needed to verify the repair.
  • A blocked evaporative emission hose can cause the pump to overheat and draw excessive current, mimicking a pump failure.
  • Some technicians replace the pump without checking the circuit, only to find the new pump also fails due to a shorted wire.
  • P1449 can be set by a weak battery or charging system issue that causes voltage spikes, so always check battery health first.

Can I keep driving with P1449?

The vehicle is safe to drive with P1449 as long as no other symptoms like fuel leaks are present, but have it diagnosed soon to avoid potential emissions test failure. Avoid ignoring a persistent fuel smell, which could indicate a safety hazard.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for BMW vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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