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Motoring Q&A: Check engine light can’t reset itself

Can the check engine light reset itself? Is there anything else I should be concerned about?


Q: We have 184,000 miles on our 2005 Chrysler Town & Country van with 3.8-liter engine. The other day my wife drove it down the block and didn't notice the red path of oil on the road. She came back immediately when she noticed the van would only "rev up and not go." The check engine light came on and she barely made back. I found that one of the hoses from the transmission control solenoid to the radiator had burst. This was an easy fix and I added 2.5 quarts of transmission fluid. The van runs and shifts normally. However, the check engine light remained on and my scan tool showed four codes — PO732, PO700, PO734 and PO700. I understand the 732 and 734 codes are for gear ratio misalignment and the 700 code is merely an informational code. My scan tool wouldn't let me clear these codes but later that day the check engine light went off after about 30 miles of driving. Can the check engine light reset itself? Is there anything else I should be concerned about?

A: No, the computer cannot erase those codes from its memory. But it can turn off the check engine light after a certain number of key on/off cycles if it does not see the problem again. This allows the system to illuminate the check engine light again if the same or some other failure occurs.

The total fluid capacity of the 41TE-AE transmission is 9.7 quarts, so the vehicle lost less than one-third of its fluid. Adding the fact that it has survived 184,000 miles, I wouldn't be particularly worried — I don't think any significant damage was done.

Q: I have an annoying whine in my 2010 Chevy Impala steering wheel. I understand it is the clock spring and would be rather expensive to fix. Can you explain what the function of the clock spring is and are there any inexpensive fixes? Are there any potential problems just living with it?

A: Actually, the total cost to replace the clock spring, according to my ALLDATA labor guide, is roughly $300. The clock spring assembly provides electrical continuity to the driver air bag through the entire range of steering wheel movement. If there is an electrical issue with the clock spring, the restraint system warning light would be illuminated.

But I question whether the whine you're hearing is actually coming from the steering column/wheel. If it is originating from the front of the vehicle as you turn the wheel, the issue is more likely related to the power steering pump or fluid. A complete flush and refill with correct power steering is inexpensive and a good preventive maintenance procedure.

Q: I hope you can answer questions concerning timing belts and timing chains. I own a 2004 2.4-liter four-cylinder Toyota Camry with 82,000 miles. My mechanic says it has a timing chain, but the maintenance schedule says to replace the timing belt at 90,000 miles but only for those models with the six-cylinder engine. Toyota dealers advise replacing the timing belt at 60,000 miles. Does my vehicle have a timing belt or a timing chain and when should a belt or a chain be replaced? I get a bit apprehensive when I am on the highway going 65 mph.

A: Your mechanic is correct, as is the owner's manual. The camshafts in this engine are driven by a steel-link roller timing chain, not a rubber cogged belt. There is no routine replacement called for with timing chains, which is an advantage over timing belts. Coupled with the fact that this is a non-interference engine, meaning there would be no valve-to-piston contact should the chain fail, no worries. As you noted, the 3- and 3.3-liter V6 engines available in this vehicle featured timing belts that require replacement at 90,000 mile intervals.



Paul Brand, author of "How to Repair Your Car," is an automotive troubleshooter, driving instructor and former race-car driver. Readers may write to him at: Star Tribune, 425 Portland Ave. S., Minneapolis, Minn., 55488 or via email at Please explain the problem in detail and include a daytime phone number. Because of the volume of mail, we cannot provide personal replies.


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