Oxygen sensor, codes P0154 and P2254

Good afternoon.

Why did you replace the O2 sensor?

Code 128 is for the thermostat in the cooling system. The engine is running too cold.

Roy

P0128
Descriptor
Probable Causes
Poor Connections or Loose Terminals At Engine Coolant Temperature (ECT) Sensor 1, ECT Sensor 2 and Powertrain Control Module (PCM)
Powertrain Control Module (PCM)
Powertrain Control Module (PCM) Update Needed
Radiator Fan
Thermostat

I took it to AutoZone and it came back with P0154 and P2254 along with P0128.

My uncle replaced the Oxygen Sensor with one he found at the Pick a Part store.

Okay, sorry to hear that. Used parts are never recommended especially electrical parts.

The 128 could be the whole issue if the sensor was reading rich from the cold engine.

I would replace the thermostat with a new one only and see if the code returns.

Roy

Thermostat Replacement
1. Make sure you have the anti-theft codes for the radio and navigation system, then write down the customer's radio station presets.
2. Disconnect the negative cable from the battery.
3. Drain the engine coolant.


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4. Disconnect the breather pipe (A), then remove the intake air duct (B).


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5. Remove the bolt (A) securing the harness cover, then remove harness cover.


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6. Remove the thermostat cover (A), then remove the thermostat (B).
7. Face the pin (C) toward the upside, install the thermostat with new rubber seal (D).
8. Install the harness cover.
9. Install the intake air duct, then connect the breather pipe.
10. Connect the negative cable to the battery.
11. Refill the radiator with engine coolant, then bleed air from the cooling system.
12. Clean up any spilled engine coolant.
13. Do the power window reset procedure.
14. Enter the anti-theft codes for the radio and the navigation system, then enter the customer's radio station presets.
15. Set the clock.

I had already replaced the thermostat before the oxygen sensor. He got the oxygen sensor from Pick a Part.

What temperature thermostat did you use?

I am not sure what he put in!

It has to be at least 195.

What is 195?

Could that cause the oxygen sensor codes pop up?

195 is the temperature of the thermostat.

Yes, as I stated before, it could have been the root cause of the other two codes.

Roy

We used the Failsafe Thermostat from Autozone. Would that matter?

The temperature is what matters. Need to know the temperature rating.

Roy

Thanks so much for your help Roy! The thermostat is 170. I have been looking online for one that is 195 but cannot seem to find anything.

You need to replace with a 195. Any parts store has these in stock.

You are welcome.

Always glad to help.

Roy

Hello Roy, I changed the Thermostat to the Honda Thermostat which now the code P0128 is now cleared. The code P0154 is still coming up.

OK, time to go back to honda parts and get the upstream O2 sensor. take out that used one and throw it away.

Roy

P0154
Descriptor
Probable Causes
Air Fuel (A/F) Ratio Sensor 1
Poor Connections or Loose Terminals At Air Fuel (A/F) Sensor 1, Air Fuel (A/F) Sensor Relay and Powertrain Control Module (PCM)