Weird Transmission Issues

[ceejay1]

Hello,

I thought I'd take my issues to the online community before I take it to the shop. I purchased this 07 Suburban (5.3) with all these issues for pretty cheap, so just trying to go through 1 by 1 and fix them.

List of codes currently have:
P0036
P0056
P0141
P0161
P0700
P0787
P1815

The symptoms I'm having is there's currently a little smoke coming from the exhaust during startup for a few seconds and goes away. I'm guessing that corresponds to the O2 Sensors.

Also, it will not shift to what I feel is past second gear. I can hit about 50, but it's pushing 3500k.

Gear shift indicator will sometimes not light. If you go down to Manual, nothing will illuminate, and it will act the same as in drive.

What I have done is replace the TCM, both shift sensors, the 3-2 sensor and Accumulator along with the filter and transmission fluid.

I have also replace both passenger side (I believe is bank 2?) Sensors.

Also, supposedly the transmission was replaced and it's always acted like this?

Really trying to focus on the transmission side of things to get it driveable, and then worry about the O2 things.

Any help would be appreciated, thanks.

 

[NickTransmissions]

P1815 is the pressure switch manifold assembly which, when it fails, can cause no upshift conditions. Did you replace that as well?

Also, the two shift solenoids and 3-2 control solenoid aren't sensors - they are linear solenoids that energize apply circuits that enable the transmission to physically change gears. The pressure switch manifold is a sensor in that it detects fluid pressurr when a goven apply circuit is "on" and relays that to the ecm so the ecm can use that data, along with a multitude of other streaming inputs to control the transmission.

 

[ceejay1]

P1815 is the pressure switch manifold assembly which, when it fails, can cause no upshift conditions. Did you replace that as well?

Also, the two shift solenoids and 3-2 control solenoid aren't sensors - they are linear solenoids that energize apply circuits that enable the transmission to physically change gears. The pressure switch manifold is a sensor in that it detects fluid pressurr when a goven apply circuit is "on" and relays that to the ecm so the ecm can use that data, along with a multitude of other streaming inputs to control the transmission.

Where is the PSM? Is it internal? I'm guessing that could be the root cause here?

 

[NickTransmissions]

Its the oblong thing bolted to the valve body/case. Three 10mm bolts and two 8mm bolts.

 

[NickTransmissions]

Where is the PSM? Is it internal? I'm guessing that could be the root cause here?

P0700 is a general transmission control fault, usually stores when there's a comm problem or TCM issue and P0787 is a shift solenoid performance code. All should resolve once you change out the pressure switch manifold assembly.

Use a multimeter to test the PWM and electronic pressure control solenoid to confirm continuity / resistance...All three shift solenoids will ohm out to between 19-22 ohms, the electronic pressure control solenoid should generate 4-6 ohms and the PWM solenoid should show between 9-11.5 ohms.

 

[Doubeleive]

a little smoke when you start it could maybe the pcv system needs attention, you could pull the valve covers off and take a look at how dirty it is inside, install a catch can.
02 sensors have no part in that (that I am aware of).
if that alone doesn't help then you could also try some oil treatments or thicker oil, generally it won't cause any problems other than some oil consumption

 

[ceejay1]

P0700 is a general transmission control fault, usually stores when there's a comm problem or TCM issue and P0787 is a shift solenoid performance code. All should resolve once you change out the pressure switch manifold assembly.

Use a multimeter to test the PWM and electronic pressure control solenoid to confirm continuity / resistance...All three shift solenoids will ohm out to between 19-22 ohms, the electronic pressure control solenoid should generate 4-6 ohms and the PWM solenoid should show between 9-11.5 ohms.

Thanks. I ordered a PSM and it should be here tomorrow. I will do some tests when I take off the pan and get back under there tonight.

 

[ceejay1]

a little smoke when you start it could maybe the pcv system needs attention, you could pull the valve covers off and take a look at how dirty it is inside, install a catch can.
02 sensors have no part in that (that I am aware of).
if that alone doesn't help then you could also try some oil treatments or thicker oil, generally it won't cause any problems other than some oil consumption

Awesome. Thank you. Once I get the transmission side of things fixed. I will start looking at this.

 

[donjetman]

07-10 Yukons & Tahoes came from the factory with defective driver side valve covers that cause the engine to burn/consume oil. The fix is a new improved valve cover, GM P/N 12570427 for the 07-08 engines. Here's a link the the GM TSB Technical Service Bulletin:
https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf

 

[ceejay1]

P0700 is a general transmission control fault, usually stores when there's a comm problem or TCM issue and P0787 is a shift solenoid performance code. All should resolve once you change out the pressure switch manifold assembly.

Use a multimeter to test the PWM and electronic pressure control solenoid to confirm continuity / resistance...All three shift solenoids will ohm out to between 19-22 ohms, the electronic pressure control solenoid should generate 4-6 ohms and the PWM solenoid should show between 9-11.5 ohms.

So I took the pan back off and I knew I wasn't crazy when I thought I didn't see it. There is no PSM?