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Intermittent POWER
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=87816
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Author:  Dent [ Wed Feb 14, 2018 10:56 pm ]
Post subject:  Intermittent POWER

I have been having intermittent boost issues that have become more frequent to the point of not being able to drive. I replaced both the vacuum valve and the vacuum modulator valve. When I first started it and took if for a drive, no boost. I drove several miles around my house and then I would get some intermittent boost, and then it seemed to return. I drove several more miles, and it seems ok. Does it take an insanely long time to build enough vacuum to run the turbo vanes? I'll drive it to work tomorrow and hope for the best. Also, no codes thrown.

Author:  flash7210 [ Thu Feb 15, 2018 7:57 am ]
Post subject:  Re: Intermittent boost

The MAP sensor should sense the lack of boost and set a P0299 underboost code.
Maybe the problem is the MAP sensor.
Or maybe it’s not a boost problem but instead a fuel system problem.

Do you have a boost gauge or a way of reading the MAP sensor? That would help narrow it down.

Author:  Dent [ Thu Feb 15, 2018 7:41 pm ]
Post subject:  Update

Drove to work this morning, or at least attempted to. Started out, first mile, no boost, or at least no power. No black smoke and no codes that my scanner can read. No CEL. After about 3 miles, started to get boost/power intermittently. At about 5 miles, full boost power, then it started to cut out. Engine hesitated and the red warning light that looks like a throttle plate with a lightning bolt came on and the engine stalled. Pulled over and restarted. CEL was on and no boost/power. Used cheapy scanner to read codes and I got P0725. Tried to clear and restart. CEL remained on, but had full boost/power. Drove 5 miles back home with full power, and switched for other car. Feels like an intermittent electrical problem now.

Author:  papaindigo [ Thu Feb 15, 2018 7:50 pm ]
Post subject:  Re: Intermittent boost

Could be electrical, check that ground geordi posted about under the battery behind the driver side headlight. I'd also carefully inspect the vacuum lines running to the vacuum reservoir that run under the coolant tank; could have an opening/closing leak.

Author:  GordnadoCRD [ Thu Feb 15, 2018 9:03 pm ]
Post subject:  Re: Intermittent boost

The little symbol you describe sounds like the one for the Throttle Position Sensor (foot pedal). Sounds kind of like that would be a good place to look. If your pressing the pedal isn't transmitting the correct value to the ECM, it could cause a condition like you describe as well.

Author:  Dent [ Tue Feb 20, 2018 8:50 pm ]
Post subject:  Re: Intermittent boost or Power?

Changed the MAP, cleared code P0700. Drove it with no power for several minutes. After a while, it would intermittently have power, but then lose it. It has no codes that I can detect with the GDE handheld programmer (used that to clear the P0700). I checked the tranny fluid and it is past the full mark. Seems to rev ok in neutral. Runs smooth, even with no power.

Author:  Dent [ Sat Feb 24, 2018 11:59 pm ]
Post subject:  New code p0706

I pulled the trigger on an Autel DS808 scanner. Can't figure out how to monitor the MAP with the scanner yet. Found another code in the TCM P0706. So far I have cleared P0725, P0700, and P0706. Baffled. I'm going to try to read the MAP with my cheapy dongle and torque pro.

Author:  Dent [ Sun Feb 25, 2018 2:10 pm ]
Post subject:  Re: Intermittent boost

Just took it for a ride. CEL right out of the garage. Started out with no power. Then intermittent bursts, then once it seemed to warm up, I had regular power. Went back to scan. I had PC121, which I think is due to a bad wheel speed sensor, and the P0706 returned.

Author:  Dent [ Sun Feb 25, 2018 5:29 pm ]
Post subject:  Re: Intermittent POWER

This is the latest. I used the DS808 to do an autoscan on several systems, and cleared a bunch of codes. Then I took it for a drive. Starts with no power, no CEL, and no PCM codes. As it warms up, I get power sometimes on acceleration, but then cuts out. Then, if I let it warm up enough, the power comes back, but cuts out intermittently. If you have a lift, and you don't turn off the ESP, and take a sharp corner, the ESP thinks the car is tipping, and cuts the power. That's just what this feels like, but it is not throwing the ESP warning light. The ESP shouldn't be functioning most of the time because I have two wheel sensors that are acting up. I ordered those, but they should have nothing to do with this. I drove for months with one bad wheel sensor.

The code P0706 continually comes back, so I guess I am going to change out this transmission range sensor. I don't think it is the throttle position sensor because with no load, the engine and throttle rev as expected. Anyone know the part number for the transmission range sensor?

Author:  flash7210 [ Sun Feb 25, 2018 6:57 pm ]
Post subject:  Re: Intermittent POWER

I’m pretty sure the TRS is in the solenoid pack on the valve body.
There is also a shift lever detent thingy on the valve body that wears out and also causes problems.
Maybe try contacting cascadetransmissions.com

It seems like your issue is related to the transmission.
If that’s the case, the transmission should be going into limp mode, limiting you to 2nd and 3rd gears only.

Author:  Dent [ Mon Feb 26, 2018 9:35 am ]
Post subject:  Re: Intermittent POWER

flash7210 wrote:
I’m pretty sure the TRS is in the solenoid pack on the valve body.
There is also a shift lever detent thingy on the valve body that wears out and also causes problems.
Maybe try contacting cascadetransmissions.com

It seems like your issue is related to the transmission.
If that’s the case, the transmission should be going into limp mode, limiting you to 2nd and 3rd gears only.


Thanks Flash. I think I am starting in first gear. There's no shift when the power on acceleration kicks in. I think you are right about the transmission, but it does not seem to be limited to only 2nd and 3rd gear, so I don't know.

Author:  Dent [ Mon Feb 26, 2018 10:24 am ]
Post subject:  Re: Intermittent POWER

flash7210 wrote:
I’m pretty sure the TRS is in the solenoid pack on the valve body.
There is also a shift lever detent thingy on the valve body that wears out and also causes problems.
Maybe try contacting cascadetransmissions.com

It seems like your issue is related to the transmission.
If that’s the case, the transmission should be going into limp mode, limiting you to 2nd and 3rd gears only.


Thanks for that website. Looks like they are not responding to any questions, and don't have contact info. Our trans is the 545RFE, right?

Author:  flash7210 [ Mon Feb 26, 2018 2:36 pm ]
Post subject:  Re: Intermittent POWER

Yes. 545rfe.

This is the correct link
http://www.cascadetransmissionparts.com/45rfe545rfe65rfe66rfe.aspx

Of course, you could always consult your local transmission shop.

Author:  Dent [ Wed Feb 28, 2018 2:53 am ]
Post subject:  Re: Intermittent POWER

I ordered the solenoid pack. Will update in a week after it comes in .

Author:  Dent [ Mon Mar 19, 2018 10:14 am ]
Post subject:  Update

I ordered and replaced all of the electronic parts including the solenoid pack, speed sensors, and the pressure transducer, for the 545RFE from Cascade transmissions. Still no power, and the p0706 code returns after being cleared. I have also tried cleaning the TCM connection with electrical contact cleaner.

Author:  flash7210 [ Mon Mar 19, 2018 11:12 am ]
Post subject:  Re: Intermittent POWER

I guess it’s time to start checking connections.

Make sure the harness connection on the transmission is locked down and tight.
Make sure the TCM is firmly connected.
Check ground connections. There is one in the corner by the TCM.
If it’s a 05 model, check the gateway module (or whatever it’s called) on the drivers side frame rail below the battery.

Author:  Dent [ Mon Mar 19, 2018 10:15 pm ]
Post subject:  Re: Intermittent POWER

Do you think it could be the TCM? It's a 2006. I already checked the TCM connection, cleaned, and replaced. I'll get on the others.

Author:  Dent [ Tue Mar 20, 2018 7:38 am ]
Post subject:  update

flash7210 wrote:
I’m pretty sure the TRS is in the solenoid pack on the valve body.
There is also a shift lever detent thingy on the valve body that wears out and also causes problems.
Maybe try contacting cascadetransmissions.com

It seems like your issue is related to the transmission.
If that’s the case, the transmission should be going into limp mode, limiting you to 2nd and 3rd gears only.


This problem has spanned two threads since it started because I thought it was originally turbo related. After taking Flash's advice of changing the solenoid pack, cleaning and reseating the electrical connections, clearing codes, and putting transmission TCM in quick learn, the problem is resolved. I also took Flash's suggestion to seek out cascadetransmissions.com. Robert at Cascade has several videos on the 545RFE, and he is very knowledgeable and helpful. Sounds like he was dealt and awful hand health-wise. If you need some transmission parts, he is a good guy running a small business that could use the help. Check out cascadetransmissions.com

Author:  flash7210 [ Tue Mar 20, 2018 12:09 pm ]
Post subject:  Re: Intermittent POWER

I’m glad you got it working :pepper:

Author:  Dent [ Thu Mar 22, 2018 1:30 am ]
Post subject:  Short lived success

Drove the Liberty to work this morning. About 7 miles into the drive, I had some power loss, and the red throttle position warning light came on twice. After that, I made it to work without any major issue. Then I drove it 17 miles home, and all seemed well except for an occasional power loss. Took if for a test drive, and the power loss was back. Scanned and the P0706 is back along with U0002 and two wheel sensor codes. If this is a wiring harness issue, I don't know how I am going to find it.

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