RTD

Good morning all, I am working on an 02 Silverado 1500 with the 4.8L and 4L60E transmission. I recently replaced all the fuel lines and afterwards have the following issue: -Codes P0785 P0758 P0753 P0740 P1860 – most electrically powered solenoids/actuators in the transmission -Check Engine Light -Most of the instrument cluster is dead (No shift indicator, RPM, speedo, fuel, temp) -Truck seems to start out in higher gear (can’t tell if second or third, but I believe it is only using 3 and 4). Things I have done: -My first thought was I damaged the transmission harness doing the fuel lines. I got under there the best I could with a flashlight but the harness doesn’t seem damaged or kinked or anything and is still in the corrugate protective sleeve. -I tested fuse IGN0 in the dash fuse box which sends power to the trans and have battery voltage coming in and going out with the key in the on position, instrument panel is still dead though. Also pulled and inspected the fuse and it looks good, not blown. -I did a lot of research and found a TSB (01-07-30-002D) and a few similar posts but nothing concrete. The TSB seems to point to the ignition switch, however it says if you do NOT have battery voltage at the ignition fuse (which I do) to replace the switch. It also says to ‘inspect the ignition voltage circuit between the fuse and the transmission for possible opens’. Beyond visual, does anyone know how to do this as far as voltage measuring points? The only related wiring diagram I could find shows power coming out of the IGN0 fuse and immediately splitting to the cluster and the transmission, but it doesn't really show it routing through the ignition switch (but according to the TSB it seems like it should...) If I’ve lost power to the transmission harness AND the cluster, then something downstream of IGN0 must be open (i.e. it shouldn’t be damage isolated to the transmission harness or the cluster would work, right?) I can’t tell if this pink power line runs through the ignition switch next and then to the cluster and transmission, which if failed is causing the open. For information I had an issue after replacing the fuel lines where the engine wouldn’t start and was cranking it over quite a bit, not sure if excessive cranking could kill that switch. Does anyone have any experience with this or a better understanding of how power is routed downstream of that IGN0 fuse? I can’t seem to find any more wiring diagrams out there after searching for hours. I'm hesitant to spend more time and money on an ignition switch if its not the issue, both of which I don't really have much of. Thanks

Hello, looking for help troubleshooting a coolant temperature sensing issue. Background on the truck: 2002 Silverado with the 4.8L. I’ve only had the truck a few months and after picking it up did a mini overhaul of it (new plugs/coils/wires, new brakes, front and rear suspension, fluids all around). After getting all that done and getting it through a drive cycle, I thought the dash gauge was reading low and sure enough I got a P0128 code for coolant temp not reaching normal operating temperature. The dash gauge read about 170ish at the time. I was dumb and didn’t get a scan tool reading. I just suspected a stuck thermostat due to the age of the truck. This weekend replaced the water pump with new thermostat as well as the fan clutch (no electric fans). Drove it to work this morning and dash gauge temperature was about 10F higher than before (sits right under 185F now). Since I was watching it like a hawk I even noticed it burp up above 185 and then come back down, which I assumed was the thermostat opening up. The thermostat I put in I believe is a 187F thermostat from Gates, so given some typical errors in the dash gauge I figured it was working ok. For the hell of it I brought my scantool with me and checked the computer’s temperature when I parked, which said 153F. This doesn’t make any sense, and I’m concerned once the drive cycle is complete I’m just going to trigger the code/check engine light again (I’m in one of those unfortunate states that requires inspections with no check engine lights). Any thoughts? I find it hard to believe it’s a stuck new thermostat and thinking something else has to be going on. I thought possibly a bad temp sending unit, but the symptoms don’t make sense to me for that either. The truck does originally have the tow package which calls for the severe duty fan clutch. Wondering if that thing is keeping things cooler than it should…

Thank you for responding - is this something I need a scan tool for your is there simpler way to check?

Forgot to add there are no check engine lights or other abnormal indications/lights on the dash. Oil pressure, battery voltage both appear normal.

Hello all, I just joined the site and looking for some wisdom. I recently picked up a 02 Silverado 1500 with the 4.8L. It was an old plow truck with only 75,000 on the drivetrain which is why I grabbed it. But since it was a plow truck with all the salt up here it was put through the ringer. I’ve basically been doing a mini-restoration on it the past few months. Aside from a ton of suspension and brake work as well as rust wars, I’ve done the following relevant to my issue: -Replaced the coil packs, plugs and wires -New exhaust headers and catalytic converters -New starter -New positive battery cable -Cleaned the throttle body -New air filter -Replaced solenoids, filter and transmission fluid -Pretty much new fluids everywhere except coolant. No real red flares in the oil when I changed it, just old. -Battery is good -Verified the throttle linkage operates smoothly -The fuel lines were replaced by the previous owner due to rot with rubber ones which look pretty good. I checked the best I could to make sure they all look connected properly but it’s pretty difficult to see in some areas underneath. Symptoms: The truck seems to be choking and running rough on startup. Some cold starts it fires right away, others it turns over more than expected given all the new parts listed above. Sometimes once it starts it really stumbles until you give it some gas. Some warm starts also exhibit the same behavior. Once it is up and running it seems to be fine, idles smoothly at 700-750 RPM, shifts decently while driving, doesn’t stall out on stops. The only other related issue I’ve had is when backing up with a full throw on the steering wheel it stalled out. I was really expecting given the mileage and work I did it would be smooth running but not so much. Any thoughts? Thanks in advance and sorry for the long post. Ryan