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Discussion Starter #1
Hello,

I am new to this forum.

I have a 2001 Rav4, with 165k miles. A few weeks ago, it started over-reving between 2nd/3rd gear. Last week, it started slipping, and, as of late, its very sluggish from a full stop and coming to one.

I borrowed a scanner from a friend, and go OBD2 codes P0141 and P1155, a combination of codes I cannot find anywhere on the internet. I know the codes relate to the O2 and A/F sensors, respectively, yet the symptoms correlated with many of the Transmission/ECU issues described in forums like this and others.

I just got my car back from the transmission shop today, with the sad news that, after a diagnostic (free of charge to me), they need to replace the transmission which would cost 3,200 plus tax.

My only hope for my beloved Rav, since switching the transmission is out of the picture financially, is to treat the ECU.

can anybody advice for or against this plan?

ps: after calling the dealer, they told me my Rav4's ECU was "reprogrammed" in 2007.

Thank you for your help.
 

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Did you read the threads about the ECU ? The fix is to have the ECU rebuilt (resoldered). Also many had to rebuild their transmission and replace their ECU to resolve their problem.

Rebuilding the ECU is the best plan. Do a search on the forum to find the ECU specialist some had success with. You would need to remove the ECU and send it out for repair.
 

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Yes I have read many of the threads regarding this issue. The reason for my posting of this new thread was because of the O2 and Air/Fuel ratio sensors showing up in the codes, instead of all of the false codes listed on ECM rebuild specialists' pages.

The transmission mechanic told me that when he plugged it in at his shop, no codes came up, but that only based on his hearing, it sounded as if the first set of planetariums were worn and needed replacement, leading to his diagnosis/conclusion that I need to replace the transmission. Its the only opinion I have gotten on my car, the rest is based on reading these forums, for which I am thankful!
 

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P0141
Verify battery voltage to the B1S2 O2 sensor heater on the Black/Red wire on the harness side at each sensor with the key ON.

Unplug the B1S2 sensor connector and ohm the rear O2 sensor heater across the wires on the sensor side of the connector that match up with the Black/Red and Red/Black wires for B1S2, specification is 11-16 ohms at 68 degrees F and 23-32 ohms at 1,472 degrees F.





P1155
Unplug the B2S1 sensor connector and ohm the front air/fuel ratio sensor heater. The heater resistance should be between .8-1.3 ohms. The Bank 2 air fuel ratio sensor is located towards the front of the engine by the alternator. This code is for B2S1.


Neither of these codes will cause a transmission to slip. Was the check engine light on? Why did you check for codes?
 
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Discussion Starter #5
P0141

Neither of these codes will cause a transmission to slip. Was the check engine light on? Why did you check for codes?
The check engine light was, and has been on, but that is a long story. I already knew it was the O2 sensor, the mount, to be precise.

I checked for codes to see if any matched the ones listed in ECM repair sites.
 

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Yes I have read many of the threads regarding this issue. The reason for my posting of this new thread was because of the O2 and Air/Fuel ratio sensors showing up in the codes, instead of all of the false codes listed on ECM rebuild specialists' pages.

The transmission mechanic told me that when he plugged it in at his shop, no codes came up, but that only based on his hearing, it sounded as if the first set of planetariums were worn and needed replacement, leading to his diagnosis/conclusion that I need to replace the transmission. Its the only opinion I have gotten on my car, the rest is based on reading these forums, for which I am thankful!

You may have two problems by the looks of things. The transmission problem is more critical and should be tackled first. A bad ECM can cause the transmission to not shift properly. Driving your vehicle can cause more damage to the transmission. Consider getting a used transmission or a reman one.
 
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