Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSBMW2009128I CONVERTIBLE (E88) L6-3.0L (N52K)REPAIR AND DIAGNOSISA L L DIAGNOSTIC TROUBLE CODES ( DTC )TESTING AND INSPECTIONP CODE CHARTSP2247
2009 BMW 128i Convertible (E88) L6-3.0L (N52K)
P2247
2009 BMW 128i Convertible (E88) L6-3.0L (N52K)SECTION P2247
2C3E - P2247
Information saved in
DME
Fault code
2C3E - P2247
Fault text
Oxygen sensor before catalytic converter 2, line fault
Fault description
O2 Sensor Reference Voltage Circuit/Open (Bank 2 Sensor
1)
Condition for fault identification
Test condition:
O2 sensor wiring monitor
O2 sensor signal freezes.
No fault memories
Drive at 50 - 80 km/h at moderate engine speed
Terminal condition: Terminal 15, engine on
Voltage condition:
none
Condition for fault memory entry
Voltage seizes at 2V (Lambda = 1) OR voltage < 2.1 V with
overrun injection deactivation active
Action in service
1. Visual inspection of wires, DME plug and O2 sensor for
damage
2. Inspect wires
3. Check plug-in connections DME <=> Wiring harness
<=> Upstream (pre-cat) O2 sensor for Bank 1 (water or
corrosion in plug?) => Repeatedly remove the plug and then
reconnect it FIRMLY)
4. Check catalytic converter (is FSD lean fault entered for
the other bank?)
5. Piston rings, injectors, positive crankcase ventilation OK?
FSD fault? Then continue there!
6. Replace O2 sensor
7. Replace DME
Fault effect and breakdown warning
Driver information
Warning light:
MIL ON
Service instruction
none
Information saved in
DME
Fault code
2C3E - P2247
Fault text
Oxygen sensor before catalytic converter 2, line fault
Fault description
O2 Sensor Reference Voltage Circuit/Open (Bank 2 Sensor
1)
Condition for fault identification
Test condition:
O2 sensor wiring monitor
O2 sensor signal freezes.
No fault memories
Drive at 50 - 80 km/h at moderate engine speed
Terminal condition: Terminal 15, engine on
Voltage condition:
none
Condition for fault memory entry
Voltage seizes at 2V (Lambda = 1) OR voltage < 2.1 V with
overrun injection deactivation active
Action in service
1. Visual inspection of wires, DME plug and O2 sensor for
damage
2. Inspect wires
3. Check plug-in connections DME <=> Wiring harness
<=> Upstream (pre-cat) O2 sensor for Bank 1 (water or
corrosion in plug?) => Repeatedly remove the plug and then
reconnect it FIRMLY)
4. Check catalytic converter (is FSD lean fault entered for
the other bank?)
5. Piston rings, injectors, positive crankcase ventilation OK?
FSD fault? Then continue there!
6. Replace O2 sensor
7. Replace DME
Fault effect and breakdown warning
Driver information
Warning light:
MIL ON
Service instruction
none
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.