Open or internally shorted switching solenoid coil on bank 2; Corroded, loose, or damaged electrical connector at the bank 2 solenoid; Broken or chafed wire in the control circuit between the DME and the solenoid; Poor ground connection for the solenoid circuit, often at the engine block or chassis; Failed DME driver stage for the solenoid control output; Vacuum or air supply leak affecting the air-assisted injection valve operation; Contamination or carbon buildup in the secondary air passages causing the solenoid to overheat and fail

DTC codes / BMW codes / P1289

P1289 · BMWSwitching Solenoid for Air Assisted Injection Valves Bank 2 Control Circuit Signal High

P1289 on a BMW means the engine control module (DME) has detected a high signal on the control circuit for the bank 2 switching solenoid that operates the air-assisted injection valves. The solenoid is commanded by the DME to open and allow secondary air into the injection stream, and a high signal indicates the circuit is seeing voltage above the expected range, often because the solenoid coil is open or the ground path is compromised.

SystemPowertrain

Code typeBMW specific

SeverityMedium

Fix difficultyIntermediate

AreaFuel and air metering (injector circuits)

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Slightly rough idle or hesitation during the secondary air injection phase after a cold start
A brief puff of black or rich-smelling exhaust on cold start if the solenoid fails to open
Intermittent misfire codes or lean-condition codes if the air-assisted injection is disrupted
Reduced fuel economy in some cases due to incorrect air metering during warm-up
Failed emissions test because the secondary air system does not function as designed

Common causes, most likely first

Open or internally shorted switching solenoid coil on bank 2
Corroded, loose, or damaged electrical connector at the bank 2 solenoid
Broken or chafed wire in the control circuit between the DME and the solenoid
Poor ground connection for the solenoid circuit, often at the engine block or chassis
Failed DME driver stage for the solenoid control output
Vacuum or air supply leak affecting the air-assisted injection valve operation
Contamination or carbon buildup in the secondary air passages causing the solenoid to overheat and fail

How to diagnose and fix it

Use a scan tool to clear the code and verify it returns, then check for any related pending or stored codes
Inspect the bank 2 solenoid connector and wiring for corrosion, looseness, or physical damage
Measure the resistance of the solenoid coil with a multimeter and compare to BMW specifications
Check for battery voltage at the solenoid connector with the key on and the circuit commanded on
Perform a voltage drop test on the ground side of the circuit to confirm a clean ground path
If the circuit and solenoid test good, substitute a known-good solenoid or use a lab scope to verify the DME driver signal
Repair or replace the faulty solenoid, wiring, or connector, then clear codes and confirm the repair with a road test

What a high signal really tells you

A high signal on this circuit often means the solenoid coil is open, so the DME sees full system voltage on the control wire instead of the expected pull-down.
Technicians sometimes replace the DME prematurely when the actual fault is a corroded ground strap on the engine block that affects multiple solenoids.
The bank 2 solenoid is frequently misdiagnosed as a bank 1 fault because the connectors look identical and are close together on some BMW engines.
A failing secondary air pump can cause the solenoid to overheat and fail, so always check pump operation before installing a new solenoid.
This code can set intermittently due to a wire that rubs through only during engine movement, so a wiggle test of the harness is essential.

Can I keep driving with P1289?

You can usually drive the car with this code, but avoid long periods of idling and cold-start short trips until it is repaired. The engine may run slightly rough during warm-up, and continued driving with a failed solenoid can lead to secondary air system damage and emissions test failure.

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.