Damaged or corroded wiring and connectors at the leak diagnostic pump, especially at the pump harness connector; Failed leak diagnostic pump due to internal electrical fault or water intrusion; Blown fuse that supplies power to the leak diagnostic pump circuit; Faulty relay that controls power to the leak diagnostic pump; Corrosion or damage in the engine control module harness connector affecting the control circuit; Internal failure of the engine control module driver for the leak diagnostic pump circuit

DTC codes / BMW codes / P1470

P1470 · BMWLeakage Diagnostic Pump Control Circuit Electrical

Q: What does code P1470 mean?

Leakage Diagnostic Pump Control Circuit Electrical. P1470 on BMW vehicles indicates that the engine control module has detected an electrical fault in the control circuit for the leak diagnostic pump, which is the pump used to pressurize the evaporative emissions system during self-checks. The computer monitors the circuit for open, short-to-ground, or short-to-power conditions and sets this code when the expected voltage or current is outside the valid range.

P1470 on BMW vehicles indicates that the engine control module has detected an electrical fault in the control circuit for the leak diagnostic pump, which is the pump used to pressurize the evaporative emissions system during self-checks. The computer monitors the circuit for open, short-to-ground, or short-to-power conditions and sets this code when the expected voltage or current is outside the valid range.

SystemPowertrain

Code typeBMW specific

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
A slight fuel odor may be present if the leak diagnostic pump is not running its self-test
Rough idle or hesitation in rare cases if the fault affects shared power or ground circuits
Failure to complete the evaporative emissions monitor, which can prevent the vehicle from passing an emissions inspection
In some models, a message on the instrument cluster indicating increased emissions or a service engine soon warning

Common causes, most likely first

Damaged or corroded wiring and connectors at the leak diagnostic pump, especially at the pump harness connector
Failed leak diagnostic pump due to internal electrical fault or water intrusion
Blown fuse that supplies power to the leak diagnostic pump circuit
Faulty relay that controls power to the leak diagnostic pump
Corrosion or damage in the engine control module harness connector affecting the control circuit
Internal failure of the engine control module driver for the leak diagnostic pump circuit

How to diagnose and fix it

Check all fuses related to the evaporative emissions system and replace any that are blown
Visually inspect the leak diagnostic pump harness and connector for corrosion, water intrusion, or damaged pins, and clean or repair as needed
Disconnect the pump and check for battery voltage at the power supply terminal with the key on, then check the ground circuit for continuity to chassis ground
Test the control circuit from the engine control module to the pump for continuity and shorts to ground or power, repairing the harness if faulty
Command the leak diagnostic pump on with a scan tool and listen for pump operation; if it does not run, test the pump directly with fused power and ground
If the pump fails direct testing, replace the leak diagnostic pump
If all wiring and the pump are good, check the engine control module driver circuit and replace the module only after confirming all other possibilities

What BMW Technicians Check First for P1470

The leak diagnostic pump is often located under the rear of the vehicle near the charcoal canister, where it is exposed to road debris and water, making harness damage and connector corrosion the most common cause of this code.
A failed leak diagnostic pump can set P1470 without any driveability symptoms, so many owners ignore it until an emissions test fails due to the evaporative system monitor not completing.
Do not replace the engine control module based solely on this code; the control circuit driver is rarely the culprit, and a thorough circuit test usually reveals a wiring or pump fault.
On some BMW models, a weak or failing battery can cause spurious electrical codes including P1470, so always verify battery voltage and condition before condemning components.
The leak diagnostic pump only runs under specific conditions such as a cold engine and a certain fuel level, so the code may be intermittent and not set during a short test drive.

Can I keep driving with P1470?

The vehicle is generally safe to drive with P1470 because the fault affects only the evaporative emissions self-test and does not impact engine performance or safety. However, you should avoid ignoring the code because it will prevent the emissions monitor from completing and may lead to a failed inspection, so have it diagnosed promptly.

Tools that help

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