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Re: Check Engine light comes on and goes off (PO125 and PO441)
Here is what I have on these trouble codes:
P0125
Insufficient Coolant Temperature for Closed Loop Fuel Control
Possible Problems
After the engine is warmed up, oxygen sensor output does not indicated RICH even once when conditions warrant and continue for at least 1.5 min.
Conditions: Engine speed 1,500 rpm or more, and speed 25-62 mph and throttle valve not completely closed.
Open or short in HO2 sensor circuit or oxygen sensor
or
Engine coolant temperature (ECT) sensor indicates that the engine has not reached the required temperature level to enter closed-loop operation within a specified amount of time after starting the engine.
Insufficient warm up time
Low engine coolant level
Leaking or stuck open thermostat
Faulty coolant temperature sensor
P0441 and/or P0446
A. Diagnostics for PO441:
1. Remove and replace Vacuum Hoses between EVAP VSV and Charcoal Canister.
2. If there is a metal vapor pipe between EVAP VSV and Charcoal Canister, clean inside of vapor pipe
3. Replace EVAP VSV and Charcoal Canister assembly with new parts.
B. Diagnostics for P0446:
1. Inspect vacuum hoses and pipes between EVAP (Purge) VSV and Charcoal Canister for leaks.
2. Replace Vapor Pressure VSV and Canister.
NOTE :When performing diagnostics for an occurrence of a MIL "ON" condition, Diagnostic Trouble Code (DTC) P0441 may be result of debris in Evaporative Emission Control System. This may cause blockage of a vapor line, or a stuck VSV, as described in troubleshooting area of Repair Manual.
Possible Problems
Open or short in VSV circuit for vapor pressure sensor
VSV for vapor pressure sensor
Open or short in vapor pressure sensor circuit
Vapor pressure sensor
Open or short in VSV circuit for EVAP
VSV for EVAP
Vacuum hose cracks, hole, blocked, damaged or disconnected
Charcoal canister cracks, hole, or damaged
The bottom line of this is: Don't neglect these codes. Bring your car to a competent mechanic. If the engine is not coming up to temperature, then it will never run right. You have to attain closed-loop fuel metering to make the engine perform correctly.
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