Home Forums Hunting & Shooting Hunter's Campfire A question for the Chevy enthusiasts among us.

I unhooked the battery today on my son's 01 Silverado. When I reconnected it, the fuel gauge was pointing straight down, and the truck would try to crank, but immediately shut off.

It also will not communicate with my code scanner. This makes me think it might be an issue with the body control module.

Does anyone know how to reset it?

Any other ideas would be appreciated as well.

First, check the fuses. There's a "keep alive" circuit that provides unswitched battery voltage to the computer. Sometimes it's labeled "Gauges". If that one blows, the computer can't communicate with the serial data port (otherwise known as the scan tool plug). When you say "crank" do you actually mean "run"? Cranking means the starter is turning the engine. If the fuel pump relay isn't getting a signal from the computer or an oil pressure switch that tells it the engine is running, the fuel pump will shut off as soon as you release the key from the "start" position, and the engine will stall.
Jerry

Our most modern vehicle is a 2003 Chev and this is good to know if a fellow is as old school as am I. The higher tech vehicle electronics - especially computer controlled stuff - can be baffling to us old guys who have not made much of a leap to that era.

Clean connections. Retighten.

Test battery.

If one has goofy electrical going on, always check your ground connections. I’ve found many times that the factory wire will be corroded in the crimp of grommet ends. Easy way to check is give them a tug. Your battery is good right ?

What was the reason for unhooking the battery in the first place?

I'd start with checking for corrosion on the battery terminals. Then a multi-meter and check for about 12VDC on the battery. Then fuses to the ECM. If you can find a pinout reading, you might can check the supply voltage to the ECM just to be sure.

If all that is good, I'd probably search on the internet a little more, but I think the ECM might be fried.

I replaced the ABS control module. The instructions that came with it said to unhook the battery.

Battery is good, connections clean. This has something to do with disconnecting and reconnecting the battery. I did it one other time, and it didn't want to start, but then finally did. After it started, there were no more problems. A google search shows this to be a common problem, but doesn't really produce a solid resolution to the problem.

This particular "old guy" is 73, but I've also spent 60+ years in the auto repair business , and 30+ years teaching auto mechanics. I HAD to learn electronics and computer diagnosis to keep current in my trade skills.
Jerry

Listen to Jerry and Jim Conrad.

You think that fuse is in the fuse box or somewhere else? I haven't found a bad fuse. The engine will turn over and fire, but immediately quit. I can hear the fuel pump when I turn the key on.

The fuel pump does a 2-second "priming run" controlled by the computer every time the ignition switch is turned from "off" to "run". This pressurizes the fuel injector rail. Most GM engines from the time of yours have a 3-terminal oil pressure switch that provides voltage to the fuel pump relay once the engine starts. In case of a rollover or any other oil pressure loss, the pump stops to minimize the fire hazard from a constant pump run. There should be a green insulated wiring connector in the wiring harness somewhere along the firewall with nothing connected to it. That's a voltage monitoring point for the fuel pump power. It can also be used to power the pump for diagnosis purposes, using a fused jumper wire. If the engine can be made to run with power on that wire, you've got an open circuit somewhere in the "run" circuit for the fuel pump. Another troubleshooting method is to find the fuel pump relay, remove it, and jumper the connectors between the "power" and "pump" terminals to run the pump continuously. If the engine starts and continues to run, find the open circuit and fix it.
Jerry

My question for “Chevy enthusiasts”.......Why! memtb

"Speed kills- - - - - -buy a Chevy and be safe!"

Difficult to conjure a simple answer to a complex question. I've been divesting the bigger ones for more than two years now, and still have at least a dozen Chev and GM trucks from 1968 through 1972. Oh - and one 1967 Corvette in case I want to go out and get killed.

Your anti theft/ passlock needs to be reset.

30 MINUTE LEARN PROCEDURE
Turn ON the ignition, with the engine OFF.
Attempt to start the engine, then release the key to ON (vehicle will not start).
Observe the SECURITY telltale, after approximately 10 minutes the telltale will turn OFF.
Turn OFF the ignition, and wait 5 seconds .
Repeat steps 1 through 4 two more times for a total of 3 cycles/30 minutes (the vehicle is now ready to relearn the Passlock(TM) Sensor Data Code and/or passwords on the next ignition switch transition from OFF to CRANK). IMPORTANT: The vehicle learns the Passlock(TM) Sensor Data Code and/or password XXXXX the next ignition switch transition from OFF to CRANK. You must turn the ignition OFF before attempting to start the vehicle.
Start the engine. The vehicle has now learned the Passlock(TM) Sensor Data Code and/or password.

Would an 01 model have that anti-theft system? Maybe it was a option back then.
Jerry

Tried that. The security light never goes off. It swaps from "Battery" to "Security" to "Low Fuel" and keeps going. Truck is full of gas before someone asks.

There is a "Security" light in the dash. I suppose it has something.

There are 2 anti theft. One is the key passcode. Second is an anti tow tilt switch. If the vehicle is lifted from the rear.