BMW Valvetronic Fault — Diagnosis and Fix

A Valvetronic fault puts your BMW into a reduced-power limp mode. Here's what's happening and how to fix it.

What You'll See

• "Drivetrain malfunction" or "Engine malfunction" warning
• Reduced power (limp mode)
• Rough idle
• Check engine light
• Fault codes: 2A67, 2A68, 2A6B, 2A70, 2A71 (Valvetronic-related)

What Valvetronic Does

Valvetronic controls intake valve lift electronically, replacing the traditional throttle body for airflow control. When it fails, the DME reverts to throttle body control — the car still runs but with reduced performance.

Common Causes

1. Eccentric Shaft Sensor (Most Common)

The sensor that tells the DME the current valve lift position.

• Symptoms: Valvetronic fault codes, rough idle, limp mode
• Why it fails: Heat and vibration degrade the sensor over time
• Fix: Replace sensor — €80-200 part, 1-2 hours labor
• Location: On the valve cover, near the Valvetronic motor

2. Valvetronic Motor

The electric motor that drives the eccentric shaft.

• Symptoms: Same as sensor failure, plus possible ticking noise
• Why it fails: Motor windings degrade, brushes wear
• Fix: Replace motor — €150-350 part

3. Valvetronic Wiring Harness

The wiring between the sensor/motor and the DME.

• Symptoms: Intermittent Valvetronic faults
• Why it fails: Heat, vibration, oil contamination
• Fix: Repair or replace harness section

4. Eccentric Shaft Actuator Gear

The worm gear connecting the motor to the eccentric shaft.

• Symptoms: Ticking noise from valve cover, Valvetronic faults
• Why it fails: Gear teeth wear over time
• Fix: Replace gear — requires valve cover removal

5. Eccentric Shaft Itself

Rare, but the shaft can seize or develop excessive play.

• Symptoms: Complete Valvetronic failure, metallic noise
• Fix: Major repair — eccentric shaft replacement

Diagnosis Steps

1. Scan for specific fault codes — they'll point to sensor, motor, or mechanical issue
2. Check the eccentric shaft sensor — most common and cheapest fix
3. Test the Valvetronic motor — apply voltage and check for movement
4. Inspect wiring — look for damaged or oil-soaked connectors
5. If all electrical checks pass — mechanical issue (gear or shaft)

Can I Drive with a Valvetronic Fault?

Yes, but with reduced power. The car reverts to throttle body control, which works but is less efficient and less powerful. Fix it when you can, but it's not an emergency.