2001 Toyota Corolla Check Engine Light Dilemma

DIABLOW1981

MEMBER
2001 TOYOTA COROLLA
4 CYL
FWD
AUTOMATIC
198,000 MILES

Hello,

I have a Corolla 01 with 200k's on it. My CE light recently turned on. I went to a local TOYOTA dealer thinking I should finally address the problem. Its been a horrible decision and I almost regret doing this.

The codes initially read 0171 and 0300 on a generic scanner tool, The dealer's mechanic told me it was a malfunctioning MAF sensor and replaced it. $550 and 100 kms later its on again and this time he told me there was an emission code PO404 suggesting that the gas cap is not tightly fitted. Another 40 bucks and 20 kms down the road its on again. I don't trust the guy or the dealership anymore. I'm wondering if its really so hard to diagnose the problem or have they replaced the wrong part altogether and are trying to cover up. They don't seem to care and I'm just furious at the total lack of customer service at a dealership!

Thanks for your time
KP

5 Replies

MMPRINCE4000

MECHANIC
8,548 POSTS

Error codes are meant as a starting point not a conclusion.

There is a flowchart that goes with every error code. The dealer is supposed to follow the flowchart and isolate the problem.

The P0404 is a EVAP code, which CAN be the gas cap or purge solenoids in the EVAP system.

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Sunday, May 17th, 2009 AT 8:19 AM

DIABLOW1981

MEMBER
3 POSTS

Appreciate your time and advise. Can this flowchart be obtained in a Haynes/other manual. Is there something I could check/clean myself before taking it back to the dealer. I have another appt. In a week and would rather try out some minor background fixes if that's feasible. I don't have an original Toyota manual. Do you reckon a Haynes would be better suited in its absence.

Thanks
KP

quote="mmprince4000"]Error codes are meant as a starting point not a conclusion.

There is a flowchart that goes with every error code. The dealer is supposed to follow the flowchart and isolate the problem.

The P0404 is a EVAP code, which CAN be the gas cap or purge solenoids in the EVAP system.[/Quote]

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Sunday, May 17th, 2009 AT 4:18 PM

MMPRINCE4000

MECHANIC
8,548 POSTS

Haynes would not have the flowcharts, just the Factory Toyota manual.

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Monday, May 18th, 2009 AT 6:36 AM

DIABLOW1981

MEMBER
3 POSTS

In your opinion could this be a software glitch causing the CL to trip. Is there a way to verify if there is a software problem

tks
KP

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Monday, May 18th, 2009 AT 11:46 AM

MMPRINCE4000

MECHANIC
8,548 POSTS

I am concerned with their diagnosis. P0171 is lean condition bank one, which is generally an O2 sensor (but could be MAF).
They should be able to check both sensors with scanner in live data mode.
P0300 is a random misfire which could be caused by an bad plug/coil (especially with 200K miles).

I would try another mechanic/garage.

They should be able to run diagnosis on PCM also.

I prefer getting a definiitive diagnosis rather than throwing parts at it.