MAP sensor voltage issues

I'm a Honda Guy · Jan 24, 2015

2001 Accord V6 auto trans 175,000 miles, owned since new.
Back probed map sensor wires between signal and ground with engine running. At idle voltage was .9V. On acceleration, voltage came up to 2.9 volts. Should it have gone up higher than 2.9V? What role does this sensor play in transmission shifting? What other sensors affect shifting? I checked both clutch control solenoids (pressure control), they were both 5.3 ohms and they clicked when voltage activated. Factory calls for 5 ohms.

xci.ed6 · Jan 24, 2015

aight, my specialty

so, what's your code?

MAP signal may be correct, but connect also a vacuum gauge

sensors can be picky about what their value is.
actuators, are not.

Give solenoids, motors, etc... ~10% tolerance, to be safe! Never worry to much about one that even measures -twice- what it's spec is, if the code is just for that, and you have checked related wiring.

I'm a Honda Guy · Jan 26, 2015

The CEL hasn't come on. I'm trying to figure out why my transmission is experiencing slipping on the upshifts, especially when cold, and a short lag on downshifts where the engine RPM revs before the downshift occurs. The downshift should be instant which shouldn't allow the engine to rev up. The reason I'm looking at the MAP sensor and anything else I can think of is because the trans slipping isn't consistent, it changes slightly every day. I figured that if the trans was having a problem, it would always react the same.

xci.ed6 · Jan 26, 2015

prolly NOT map sensor...

check trans fluid, BRIGHT red?
no-change

how long since you did a D&F?

I'm a Honda Guy · Jan 27, 2015

Trans fluid is bright red. Trans fluid is serviced regularly with Honda fluid.

I'm a Honda Guy · Jan 27, 2015

This shifting issue came about before I changed the trans fluid and remained the same after I changed the fluid

xci.ed6 · Jan 27, 2015

damn, well -USE HONDA ATF-, but you might doing it, and with no MIL...

well, sorry to do this, but as long as everything you can find looks correct...then take it to a dealer.

Not that I can't or don't try to help with all problems, I would want to 'feel' (literally) the problem. Your trans may have reached the end of life

If you let them mess with it for an hour, they're no better or worse than me, hopefully they have a 'softer' impact after working with it