Back to 2003 BMW 525iT E39

2003 BMW 525IT E39

2.5L I6 M54 TouringRWDAUTOMATICgas
Repairs0Labor595Torque2406Fluid7DTC722Battery0Maintenance0Recalls0
P0140moderate severityPowertrain

O2 Sensor Circuit No Activity Bank 1 Sensor 2

on 2003 BMW 525iT E39 2.5L I6 M54 Touring · RWD

What this code means

The downstream O2 sensor on Bank 1 shows no switching activity.

Symptoms

  • Check Engine Light
  • No catalyst monitoring

Common causes

  • Faulty sensor
  • Heater circuit failure
  • Wiring open

Diagnostic steps

  1. Test sensor voltage
  2. Check heater
  3. Inspect wiring

Repair notes

Replace downstream O2 sensor.

Other Powertrain codes on this vehicle

Building an app?
Free API access to all this data — 50 requests/day, no card required.
Get an API key →
Run a shop?
Manage repairs, estimates, and customers with ShopBase — $249/mo, all features included.
Try ShopBase →