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P0125 Diagnostic Issue on 1999 Mitsubishi Galant GTZ 3.0L - Engine Light On After Replacement

Model: Mitsubishi Galant Fault Code: P0125 Posted: 2014-05-18 19:44

Hello everyone, I'm currently working on my 1999 Mitsubishi Galant GTZ with a 3.0L engine and preparing it for emissions testing. Recently, the engine warning light activated, and after running a diagnostic, my friend identified error code P0125. P0125 typically indicates one of the following: • Insufficient warm-up time • Low engine coolant level • Leaking or stuck-open thermostat • Faulty coolant temperature sensor (ECT) I have already replaced the ECT sensor, thermostat housing, thermostat, and thermostat switch with OEM parts directly sourced from Mitsubishi. After resetting the vehicle's computer, the issue returned after 3 to 4 days. The emissions deadline is July 10th, and I'm now at a loss as to what might be causing this recurring fault. Can anyone provide insight or suggest further troubleshooting steps? Any experience with P0125 on this model would be greatly appreciated. Thank you in advance for your help!

Related fault codes
P0125
Comments (3)
Anonymous 2014-05-19 07:33

Has the same P0129 code reappeared after part replacement? Were OEM or aftermarket components used?

Anonymous 2014-05-19 19:00

If all original equipment manufacturer (OEM) parts were properly installed, potential causes could include a wiring fault, an undetected coolant leak, or a malfunctioning engine control module (ECM).

Anonymous 2014-05-19 21:33

Thanks for the response — yes, the same P0125 code has returned. I used OEM parts from Mitsubishi. I'll inspect the wiring connections and check for any signs of coolant leaks or ECM issues this weekend. Appreciate your input!