Search results
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Coolant and fuel temp reading negative
This. The ECT and fuel temp sensors are negative temp coefficient resistors, negative temp values = open circuit. ECT sensor and fuel temp sensor both wire independently to the ECM. ECT is C1-74 and C1-80 (reference). Fuel temp sensor is C2-25 and C2-60 (reference). Both circuits go... -
Trans or electrical issue?
Please post back with what you end up finding out to help others in the community. :)- dndj
- Post #6
- Forum: Mike L's Trans Talk
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Trans or electrical issue?
Both of those point to internal transmission issues (trans pressure switch B/E stuck) which could indicate electrical connections. Check the bulkhead connector on the trans, check for fluid in the connector. Also unplug/reseat the connectors on the TCM. If the gear selector indicator under...- dndj
- Post #4
- Forum: Mike L's Trans Talk
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06 P0193 only after 40 min drive
The fuel pressure sensor is around $300, may want to do some more investigation of connections first. The fuel pressure sensor has 3 wires - ground, +5v, and the signal which tells the ECM what the fuel pressure is. This signal to the ECM usually ranges from something like 0.5v to 4.8v... -
06 P0193 only after 40 min drive
Strongly recommend starting by replacing the FRP sensor (Fuel Rail Pressure sensor) or look for a short of the sensor output wire to the +5v reference for the sensor. Code P0193 sets when the output voltage from the sensor is too high (out of range - like greater than 175 MPa). It's likely... -
P0090 And P0088
You need to be seeing +12v at the FPR on the purple/white wire. This power comes from the ECM. There are connections in between the ECM and the FPR. Suggest tracing this back systematically to the ECM source. Even though the FPR purple/white wiring seems to be the same on all LB7s, as... -
P0090 And P0088
What year is your truck? Please fill out your profile or otherwise provide more detail so we can try to help. -
GM TECH2 scan tool and OBD2TOOL seller
Glad it worked out. :) One other option would be to use a Tech2 to initiate the TCCM relearn without having to pull it from the truck. My Tech2 is a chinese clone btw, works just fine so far no issues, but my LB7 doesn't have a TCCM relearn. GM must have changed something after the...- dndj
- Post #10
- Forum: The Tool Crib
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GM TECH2 scan tool and OBD2TOOL seller
New TCCMs out of the box need to be flashed with a calibration for the truck. My LB7 manuals nor does my Tech2 show any relearn procedure, so I can't be of much help, but I posted some pictures of the ATC (active transfer case - LOL) screens from my Tech2. There is one command available to...- dndj
- Post #7
- Forum: The Tool Crib
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GM TECH2 scan tool and OBD2TOOL seller
The 2007/2008 split in operability is likely referring to when GM began to transition away from the Tech 2 to their new PC-based GDS2 diagnostic package which interfaces to the vehicle with what they call an MDI module, using SAE J2534 interface standard. The full GM 5 year conversion window...- dndj
- Post #5
- Forum: The Tool Crib
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Edge CTS 2 vs CTS 3
My CTS2 works almost perfect. About once in 20 or so startups, it refuses to read the trans gear PID and displays "P" the entire time. I also will get the random "could not connect" at startup even more infrequently, sounds like the same thing you're reporting MAXX. Pulling the plug and...- dndj
- Post #5
- Forum: Duramax Tuning, Logging, and Gauges
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High engine temps
How long has it been since you cleaned the cooling stack? Mine started running warm on climbs, I flexed the AC condenser out of the way enough to get to the radiator directly with a hose, and ended up pulling the intercooler out as well and washing it out well. No more running warm after that... -
1/4 mile time slip evaluation and feedback
Just curious, as I'm set up similar with tuning, lift pump, and built trans. Stock tires, but I'm carrying +700lbs for the steel flatbed. What kinds of EGTs do you see running the 1/4?- dndj
- Post #9
- Forum: Drag Racing
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New here
Welcome. Lots of info for you here at this link: Thread about L5P knock. Post #22 has a link to a GM techlink article.- dndj
- Post #2
- Forum: Introductions
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lb7 dsp5 help
If you wanted to just test the tunes, you could temporarily set the DSP5 switch type to Serial Data and use the V2 to select the tune. Seems like a switch wiring issue from what you're describing.- dndj
- Post #5
- Forum: Tune Library
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LB7 CRANKS BUT NO START
Well that's one way to "fix" a crank-no start problem permanently. ;) Bummer about the fire but glad you're OK. (y) -