Tachometer Bouncing Issue/ECU - info

[TundraSC]

I didn't find much here regarding this, but resolved it yesterday and thought I'd share the info:

I've got a 2007 LE Automatic @ 78K miles. The tach began bouncing weeks ago, then the Check Engine light came on (not at the same time). The actual RPM's did not change physically, so I thought it had more to do with the sensing of the RPM's, but in an automatic I wasn't too worried about it. Gas mileage remained unchanged.

When Check Engine light came on, I took it to Autozone for free code reading. It referred to "exhaust issue." Research told me about the ECM/ECU issue and related warranty repair through 80K miles. Although it did not run rough, shift hard, stall or seem impeded, with 78,800 miles on it, I took it to the dealer.

Dealer stated that I had two codes referring to the O2 sensors only. I did not have the code relating to the bad ECU. When I told him about the tach bouncing he was intrigued and changed the ECU under the warranty. This DID stop the tach bouncing problem, so I thought I would share it.

He said the 2 oxygen sensors should be replaced, but he did not have them in stock - luckily in this case, because he said the job was $520 and NOT covered under the 80,000 mile warranty. Not having the sensors made it easy to say no thank you and leave (but not before saying that I could run to Autozone and pick them up for about $200! - he didn't see the humor in it.)

That's my information for you. Now a question for you - Does anyone happen to know if the o2 sensors should be covered under the warranty? My state does not have emmissions testing, which might make a difference.

I'd appreciate knowing what you've experienced. Thank you.

[mikered30]

O2 sensors are not covered under any warranty. What was the code? It wasn't P0420 was it? Hard to believe a 2 year old car needs new 2 O2 sensors so soon. I hope the dealer isnt trying to stiff you. It is also odd he changed the ECU for you, even though he did not see any evidence of it, he just took your word on it. If you do decide to replace the sensors, don't get Bosch, get Denso or NGK sensors.