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Recurrent Check Engine
2000 Avalon XLS
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Discussion Starter · #1 ·

I have a Check Engine Light problem, and I need some sound advice!

2000 Avalon XLS with 140,000 miles. Original owner. Highway driving 30 miles round trip 5 days per week to work. No dusty roads, I live in southeastern Pennsylvania, temperate climate. Full explanation of my situation follows my questions.

1. How is Oil Gelling diagnosed?

2. Who is best qualified to diagnose oil gelling? Since the dealer is not responsible for the condition (Toyota USA is responsible), I assume the dealer would not care either way, since he has nothing to lose.

3. If oil gelling is the problem, how can this be corrected?

4. How can I reset the CEL (aka clear the codes) without having access to OBD II scanner? If I disconnect the ground of the battery, what precautions should I take?

5. Do I have to disconnect the wires to the Mass Air Flow Sensor in order to clean it with CRC Mass Air Flow Sensor Cleaner (in aerosol can)?

6. Any idea why hardly any mechanics have even heard of oil gelling?

I bought my 2000 Avalon XLS in August 2000, and the time period for which Toyota will pay for repairs associated with oil gelling has expired. I get regular oil changes, about once every four months. The longest mileage I have gone without an oil change is about 6,000 miles.

Here is the history of my CEL problem:

August 2007. 119,898 miles. CEL Light comes on. My air filter had 33,000 miles on it. Code P1130. Dealer replaced O2 Sensor 1, Bank 1. Dealer cleared codes.

September 2007. 121,000 miles. CEL light comes on again. I still had not changed air filter. Code P0171. Local mechanic replaced Mass Air Flow Sensor and cleaned throttle body. Mechanic cleared codes.

November 2008. 137,000 miles. CEL light comes on. Same air filter, now has about 50,000 miles on it (I know, stupid on my part). Codes P0171, P1150, P1155. I decline service and continue to drive with CEL on. Codes mean:

P1150: Air/Fuel Sensor Circuit Range/Performance. (Bank 1 Sensor 2)
P1155: Air/Fuel Sensor Heater Circuit. (Bank 1 Sensor 2)
P0171: System Too Lean (Bank 1)

March 2009. 140,000 miles. I FINALLY replace air filter. I clean out air filter housing. All hoses from air filter housing to manifold seem in good condition, nothing loose or leaking to me. I take out Mass Air Flow Sensor and clean with computer de-duster compressed air. I fill tank with gas and add Fuel Injector Cleaner to gas tank.

Now, I have not tried to reset the CEL myself. No mechanic will do anything with the OBD II without charging me $90. I am wondering how I can reset the codes without frying myself or the battery.

116 Posts
Your questions are interesting. Thanks for posting. I don't have answers only some guesses.

- People call it sludge not gelling
- Your A/F sensor has a bad heater element, but still works OK.
- You need a OBD scanner. You'll have yourself money by buying one.

Premium Member
6,403 Posts
Remove a valve cover and check for sludge buildup.

Sludge and cleaning the MAF sensor has been discussed many times at TN, conduct a searh of past posts.

The Camry with V6 option has the same engine and is almost the same car.

Try removing the EFI fuse to clear the codes.

Try removing the EFI fuse for 90 seconds to clear the codes.

The new codes refer to a differant O2 sensor from the one replaced.

Parts outlets such as AutoZone may read the codes or loan out readers.
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