Quote:
Originally Posted by spannerrash
If sluggish you can get an incorrect reading and this a weak or rich fuel mixture. This will though be picked up by the O2 sensors and the fuel trims altered to bring back to spec.
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This is, ironically, exactly how a bad MAF can kill a gearbox. As Marty said, the ECU feeds the engine load signal to the TCU by way of the MAF value. If that's wrong then the TCU can try to shift while the engine is still producing torque and that puts some nasty loads through the gearbox. In some cases it shifts so hard its like being shunted from behind., and eventually breaks things inside the 'box. The engine still appears to run fine though as its running closed-loop with the O2 sensors.
There is a very useful diagnostic mode in the ECU whereby if you read a particular measuring block it turns the O2 sensors off and runs open-loop on the MAF only. If it runs like crap at this point, or indeed anything other than perfect, the MAF is failing and needs replacement.
16th October 2017, 08:32 AM
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