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 CHARTSP0155(DME) CONDITION FOR FAULT MEMORY ENTRY - 1
2009 BMW 128i Convertible (E88) L6-3.0L (N52K)
(DME) Condition For Fault Memory Entry - 1
2009 BMW 128i Convertible (E88) L6-3.0L (N52K)SECTION (DME) Condition For Fault Memory Entry - 1
2CA7 - P0155
Information saved in
DME
Fault code
2CA7 - P0155
Fault text
Oxygen sensor heating before catalytic converter 2, function
Fault description
O2 Sensor Heater Circuit (Bank 2 Sensor 1)
Condition for fault identification
Test condition:
Check O2 sensor heater; sensor too cold
Terminal condition: Terminal 15, engine on
Voltage condition:
none
Condition for fault memory entry
O2 sensor temperature < 680 °C for more than 5 sec.
Action in service
1. Visual inspection of wires, DME plug and O2 sensor for
damage
2. Check wires (including resistance)
3. Check plug-in connections DME <=> Wiring harness
<=> Upstream (pre-cat) O2 sensor for Bank 2 (water or
corrosion in the plug? => Repeatedly disconnect the plug
and then FIRMLY press it back in)
4. Replace O2 sensor
5. Replace DME
Fault effect and breakdown warning
Driver information
Warning light:
MIL ON
Service instruction
none
Information saved in
DME
Fault code
2CA7 - P0155
Fault text
Oxygen sensor heating before catalytic converter 2, function
Fault description
O2 Sensor Heater Circuit (Bank 2 Sensor 1)
Condition for fault identification
Test condition:
Check O2 sensor heater; sensor too cold
Terminal condition: Terminal 15, engine on
Voltage condition:
none
Condition for fault memory entry
O2 sensor temperature < 680 °C for more than 5 sec.
Action in service
1. Visual inspection of wires, DME plug and O2 sensor for
damage
2. Check wires (including resistance)
3. Check plug-in connections DME <=> Wiring harness
<=> Upstream (pre-cat) O2 sensor for Bank 2 (water or
corrosion in the plug? => Repeatedly disconnect the plug
and then FIRMLY press it back in)
4. Replace O2 sensor
5. 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.