P1129 on 1996-1999 Honda Civic — Closed Loop Fueling Not Achieved - Bank 2
1 vehicles · 1 makes · $40-$180 repair
Most Reported On
P1129 is an OBD-II diagnostic trouble code meaning “Closed Loop Fueling Not Achieved - Bank 2.” Bank 2 version of P1128: the PCM was unable to establish closed-loop fuel control on the second bank within the expected time, leaving fueling on the open-loop table with degraded economy and emissions. This code is most commonly reported on 1996-1999 Honda Civic, with repair costs ranging from $40 to $180.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
P1129 does not use the standard P/B/C/U prefix. It may be a manufacturer-specific code, so verify that a scanner supports your exact year, model and module before buying.
Vehicles Affected (1)
FAQ
What does P1129 mean?
P1129 stands for "Closed Loop Fueling Not Achieved - Bank 2." Bank 2 version of P1128: the PCM was unable to establish closed-loop fuel control on the second bank within the expected time, leaving fueling on the open-loop table with degraded economy and emissions.
What are the most common causes of P1129?
The most common causes of P1129 are: Stuck-open thermostat / engine never reaching operating temperature, Bank 2 upstream oxygen sensor or its heater circuit failed, Exhaust leak ahead of the bank 2 sensor, Failed engine coolant temperature sensor, Wiring or connector corrosion at the bank 2 sensor. The specific cause varies by vehicle.
How much does it cost to fix P1129?
Repair costs for P1129 range from $40 to $180, depending on the vehicle and root cause.
Which vehicles are affected by P1129?
Au7o has documented P1129 across 1 vehicle models from 1 manufacturers: Honda.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.