How to replace Closed Loop Fuel Control? - Cars & Trucks

Definition of Diagnostic Trouble Code P1148 Audi: Oxygen Control (Bank 2) System too rich Ford: Closed Loop Control Malfunction Infiniti: Closed Loop (Bank 1) Land Rover: Lambda trim post-catalyst bank 1.Short circuit to ground Lincoln: Closed Loop Control Malfunction Mazda: Generator 2 Control Circuit Mercedes: IAT Sensor Circuit Malfunction, Bank 2 Mercury: Closed Loop Control Malfunction Nissan: Closed Loop Volkswagen: Oxygen Control (Bank 2) System too rich

I thinking you're right. The ECU controls everything concerning the Engine. I had to replace mine in my 1985 B944. They aren't cheap!
Cost approx. $500.00! But... I would check with your local Porsche dealer/mechanic before replacing it! Also... if the fuel injectors are clogged, or the fuel pump is bad... you may get the same problem.

closed loop control fault; when a vehicle is in closed loop, the comuter reads the O2 sensors and regulates the fuel supply accordingly in order to maintain a 14.7 to 1 ratio of air to fuel. if the sensor does not respond as expected, this code sets. it does not mean it is a bad sensor, it requires diagnosis

Hi there:
The Powertrain Control Module (PCM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop the PCM determines fuel delivery based on sensor signals, without oxygen sensor (O2S) input. During Closed Loop, the oxygen sensor inputs are added and used by the PCM to calculate Short and Long Term fuel trim, fuel delivery adjustments. If the oxygen sensors indicate a lean condition, fuel trim values will be above 0 percent . If the oxygen sensors indicate a rich condition, fuel trim values will be below 0 percent. Short Term fuel trim values change rapidly in response to the heated oxygen sensor (HO2S) voltage signals.


I suggest to check other generic details HERE.


Hope helps.

service the engine.. change oil ,filter plugs etc

did you clear the faults before each read
Diagnose Buick 3800 Engine
unusual code that

P0125 is the OBD-II generic code for the engine computer, or Engine Control Module (ECM), not detecting enough heat in the cooling system before the fuel management system can take control. The ECM has a predetermined value after you start your vehicle to expect a certain coolant temperature

P0125 OBD II Trouble Code Insufficient Coolant Temperature for Closed Loop...

ecm runs the engine cooling fans

3800V6 engine over heating and heater produces cold air
try these

EGR vale not working
overheating
inlet manifold gasket leaking
water pump fins corroded
soft radiator hoses
try a new radiator cap

internal heating
heater control tap stuck
directional actuator flaps stuck

P1148 closed loop control,, this means the computer does not see closed loop , the problem could be a bad air fuel sensor also called oxygen sensor this is the top one before the converter, check the wiring to sensor and connection if that is good then replace the sensor, this sensor on this nissan is called an air /fuel sensor and are costly. good day

DTC P2187: Fuel Trim System Lean at Idle

Fuel Trim Description
The Engine Control Module (ECM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop, the ECM determines fuel delivery based on sensor signals without Heated Oxygen Sensor (HO2S) input. During Closed Loop, the HO2S inputs are added and used by the ECM to calculate short and long term fuel trim fuel delivery adjustments. If the HO2S indicate a lean condition, fuel trim values will be above 0%. If the Heated Oxygen Sensors (HO2S) indicate a rich condition, fuel trim values will be below 0%. Short term fuel trim values change rapidly in response to the HO2S signals. Long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7 : 1.

This code can only set when the engine control is in Closed Loop. The engine must be fully warmed up.

This must be diagnosed using a scan tool that can read engine data in order to determine the actual cause of the problem. It can be caused by the following things:

> Vacuum leaks
> Malfunctioning, dirty, or skewed Mass Airflow Sensor (MAF)
> Malfunctioning or skewed Manifold Absolute Pressure Sensor (MAP)
> Dirty or sticking injectors
> Malfunctioning or improperly programmed Powertrain Control Module (PCM)

P1148 - Closed Loop Control Function Bank 1
This mean that the closed loop control function for bank 1 does not operate even when vehicle is driving in the specified condition.

The Powertrain Control Module (PCM) or Electronic Control Module(ECM) monitor the function of the Front Oxygen (O2) sensor or Air/Fuel (A/F) sensor by comparing the signal with the Rear O2 sensor.

Symptoms:
- Engine Light ON (or Service Engine Soon Warning Light)

Possible causes:
- Harness or connectors Front Oxygen (O2) sensor or Air/Fuel (A/F) sensor 1 circuit is open or shorted.
- Front Oxygen (O2) sensor or Air/Fuel (A/F) sensor bank 1
- Front Oxygen (O2) sensor or Air/Fuel (A/F) sensor bank 1 heater

Possible solution:
- Repair harness or connector. If repair is needed
- Replaced Front Oxygen (O2) sensor or Air/Fuel (A/F) sensor bank 1


Then, possible causes are faulty harness or connectors to the air fuel ratio sensor, a faulty air fuel ratio sensor (1) or faulty air fuel ratio sensor (1) heater. Most likely yes it is just faulty sensor. Just replace this devices and reset the stored codes.

Keep us updated.

WHEN ENGINE GOES CLOSED LOOP TO OPEN LOOP.YOU HAVE A RICH FUEL MIXTURE.YOU HAVE A VACUUM LEAK.BY YOU HAVING ROUGH IDLING.AND A HIGH MILEAGE ENGINE I WOULD DO A COMPRESSION TEST OR CYLINDER LEAK DOWN. CHECK FOR LEAKING VALVES AND LOW COMPRESSION .THEY BOTH WILL CAUSE ENGINE TO IDLE ROUGH CAUSE MISFIRE.CAUSE OPEN LOOP CONTAMINATE HO2 SENSOR CAUSE A RICH FUEL MIXTURE.

Insufficient Coolant Temperature For Closed Loop Fuel Control. Bad thermostat most likely.