Mechanics

TOYOTA AVALON COOLANT PROBLEM

1997 Toyota Avalon • 84,000 miles

This Avalon has a PO125 error and I have done every basic suggested fix but it still is registering.

Replaced coolant
Bled Coolant
Replaced Thermostat
Replaced Coolant temperature sensor
Replaced both upstream O2 sensors - Denso Only
Cleaned MAF sensor
Cleaned PCV valve
New Spark Plugs
New Valve cover Gaskets
Checked for blown fuses - two banks of fuses - engine compartment
Replaced air filter


Suspecting - Fans, fan switch, Fan relay. Fans have not come on since working on this car. (My mothers car) I own a 2002 sienna with same engine and I recently replaced hoses and coolant and fans were running even before van reached operating temperature. I have OBDII code reader/analyzer and have been resetting this 125 code. Could the fan topics I listed be creating this PO125 code? If so what is a good way to test each of these before just buying and putting in new parts? I also read the ECU might be the issue. I also read that the gas cap could be the issue? Help : )

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Guest
January 29, 2013.



I suggest stop throwing parts at it and get a proper diag. It would have saved you a ton of money.

This is an air/fuel ratio issue that needs to be monitored by a scan tool. Do not erase the light as it contains freeze frame data at the time of the failure.

It could be as simple as a coolant sensor, exhaust leak or injectors needing cleaning.

Roy

ASEMaster6371
Jan 29, 2013.
I will clean the injectors next. I have replaced the coolant sensor and recently had the exhaust checked and repaired as the flex pipe was broke.

Thank you for the advice. I will follow-up with my result of the injector cleaning.

Tiny
Sweetwally
Jan 29, 2013.
No additives, they rarely work. Have a professional cleaning done

Roy

ASEMaster6371
Jan 29, 2013.
I did this work on my Sienna as you are correct. I tried additives and it did not solve my issue with it. I took the throttle body apart and soaked it and issue was fixed. It was thick and black. The van would not start on its own as the gas was getting absorbed by the muck. I put a new gasket when reassembling.

Tiny
Sweetwally
Jan 30, 2013.
Good job

ASEMaster6371
Jan 30, 2013.
After doing all of these sensor and maintenance replacements, I cleaned out the throttle body and the issue is resolved. I got a temporary PO110 code but that is because I flooded the throttle body because it was caked with sludge. When I started it up, I had a white cloud of smoke from it burning off the cleaner. I did a reset of the 110 code and ran the car for : 30 mins and no code. I also added cleaner to the tank after the throttle body cleaner long burned off.

Tiny
Sweetwally
May 21, 2013.