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
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.
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.
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.
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.
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
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!"
My question for “Chevy enthusiasts”.......Why!
memtb
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.
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
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.
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
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
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.
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.
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.
Would an 01 model have that anti-theft system? Maybe it was a option back then.
Jerry
There is a "Security" light in the dash. I suppose it has something.
Would an 01 model have that anti-theft system? Maybe it was a option back then.
Jerry
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.
Would an 01 model have that anti-theft system? Maybe it was a option back then.
Jerry
There is a "Security" light in the dash. I suppose it has something.
Try flipping the key around and do it again.
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
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.
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.
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.
Communication errors.
There will be some high number codes.
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
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.
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.
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.
Communication errors.
There will be some high number codes.
Right, but I can't get a code because of the communication issues. I wish the truck just had a "do-over" button.
I guess I need to just leave chit alone. All I wanted to do was to get the brake light in the dash turned off before my son took the driver's test.
Is it insured? a couple of cans of lighter fluid applied to the tires is almost impossible to trace. I knew a guy from Chicago who made a pretty good living "arranging" insurance claims on big Diesels that way.
Jerry
Is it insured? a couple of cans of lighter fluid applied to the tires is almost impossible to trace. I knew a guy from Chicago who made a pretty good living "arranging" insurance claims on big Diesels that way.
Jerry
LOL! In the long run that might be the cheapest option, but I ain't that kind of guy.
I'm sure it's something simple.
May sound stupid, but if it has security it will lock out all comm to a scanner. If it starts and immediately shuts off it’s a security issue not comm. now here’s the stupid, take your key fob and lock and unlock the doors 3 times, then try to start it.
I have an '02, had the battery disconnected a few times. Maybe I'm lucky, hooked back up and no issues. Knock wood.
May sound stupid, but if it has security it will lock out all comm to a scanner. If it starts and immediately shuts off it’s a security issue not comm. now here’s the stupid, take your key fob and lock and unlock the doors 3 times, then try to start it.
Bought the truck used and did not get a key fob with it. Is there another way to reset?
Not stupid at all. I expect it's something about that simple.
Not that I know of, that said my last help would be to disconnect the negative battery terminal only. Let set for 30 min or longer to drain down the system capacitor. This should cause the ECM to reboot and go into learning mode which will hopefully clear all the soft codes including security. If it has any hard codes they will remain but it just might let you talk to it after reboot, key word is might. After that it’s dealer time.
It seems to be the replacement abs control module. I can unplug it and the truck runs fine. Plug it back in and truck will not run. Is there a way to somehow sync the new module with my truck, or is the new module bad?
Easy way to test is when the ignition is to on only the abs on that year you should hear a self test groan or cycling of the system. I take it your scanner/ECM is not ABS compatible otherwise you could talk to it. Some of the early years had a separate ABS connector hidden away, if I remember right my 04 Envoy was under the console and I know that’s where it’s at in my 04 Jeep. Best guess is separate ABS plug.
Sync may be possible but doubt it, so best guess is bad module on that.
Easy way to test is when the ignition is to on only the abs on that year you should hear a self test groan or cycling of the system. I take it your scanner/ECM is not ABS compatible otherwise you could talk to it. Some of the early years had a separate ABS connector hidden away, if I remember right my 04 Envoy was under the console and I know that’s where it’s at in my 04 Jeep. Best guess is separate ABS plug.
Sync may be possible but doubt it, so best guess is bad module on that.
The security light also flashes no with the new ABS control module plugged in. My code scanner does read abs, but will not communicate with the truck when the new module is plugged in.
It is a rebuilt module from ebay. Probably bad.
Simple solution- - - -leave the ABS module unplugged. How often do you get into a panic stop situation where the ABS cycles, anyway? With a non-functional ABS system, the brakes simply revert back to a normal dual-line brake setup- - - -they don't quit working. Put a piece of electrician's tape over the ABS warning light and drive on!
Jerry
Simple solution- - - -leave the ABS module unplugged. How often do you get into a panic stop situation where the ABS cycles, anyway? With a non-functional ABS system, the brakes simply revert back to a normal dual-line brake setup- - - -they don't quit working. Put a piece of electrician's tape over the ABS warning light and drive on!
Jerry
I would, but it's my kid's truck. I doubt they'd let him take his driver's test with a warning light on in the dash. Also, if he wrecks it, I'd like to know I did all I could to ensure the truck is safe to drive. Were I driving it, i'd have never given it a second thought.
Where in the world do you live, that a driver's license examiner is that anal-retentive????????? Lincoln County Tennessee certainly doesn't do a detailed vehicle inspection before a driving test!
Jerry
Easy way to test is when the ignition is to on only the abs on that year you should hear a self test groan or cycling of the system. I take it your scanner/ECM is not ABS compatible otherwise you could talk to it. Some of the early years had a separate ABS connector hidden away, if I remember right my 04 Envoy was under the console and I know that’s where it’s at in my 04 Jeep. Best guess is separate ABS plug.
Sync may be possible but doubt it, so best guess is bad module on that.
The security light also flashes no with the new ABS control module plugged in. My code scanner does read abs, but will not communicate with the truck when the new module is plugged in.
It is a rebuilt module from ebay. Probably bad.Yup. Rebuilt computer modules is never a good thing, especially FleaBay.
Easy way to test is when the ignition is to on only the abs on that year you should hear a self test groan or cycling of the system. I take it your scanner/ECM is not ABS compatible otherwise you could talk to it. Some of the early years had a separate ABS connector hidden away, if I remember right my 04 Envoy was under the console and I know that’s where it’s at in my 04 Jeep. Best guess is separate ABS plug.
Sync may be possible but doubt it, so best guess is bad module on that.
The security light also flashes no with the new ABS control module plugged in. My code scanner does read abs, but will not communicate with the truck when the new module is plugged in.
It is a rebuilt module from ebay. Probably bad.Yup. Rebuilt computer modules is never a good thing, especially FleaBay.
Lol! They had good reviews. What I get for being a tightwad.
I bet bad stuff would happen if I cranked the truck then plugged in the module.
I really appreciate all the help!!!
LOL, nope isn’t about being a tightwad. Just seems that every time I did it even with positive reviews, I always seemed to get the defective one. Had one good experience on a guy who replaced gauge stepper motors. Backed his work. Went out of business though.😃
Personally I never ever skimp when it comes to the braking system. Too damn many bad drivers out there.
LOL, nope isn’t about being a tightwad. Just seems that every time I did it even with positive reviews, I always seemed to get the defective one. Had one good experience on a guy who replaced gauge stepper motors. Backed his work. Went out of business though.😃
Personally I never ever skimp when it comes to the braking system. Too damn many bad drivers out there.
I agree. If the kid wrecks his truck, I don't want it to be my fault. I may just get a refund and buy a new one. I've messaged the guy I bought it from. We'll see what he has to say. He might know an easy fix.
Where in the world do you live, that a driver's license examiner is that anal-retentive????????? Lincoln County Tennessee certainly doesn't do a detailed vehicle inspection before a driving test!
Jerry
I live in Lafayette, but the closest DMV is in Gallatin. The most anal retentive bunch of folks I've ever seen gathered in one building.
My question for “Chevy enthusiasts”.......Why!
memtb
Build your skills as a shade tree mechanic like me.
I never get to work on the Fords, Honda, or Toyotas sitting around here.
Wrong fugging part!
They will make it right.
Thanks again for all the help. Hope you all had a great holiday!
It's either the points or the condenser,
What else could it be?
Wrong fugging part!
They will make it right.
Thanks again for all the help. Hope you all had a great holiday!
😀 good they are making it right.
I live in Lafayette, but the closest DMV is in Gallatin. The most anal retentive bunch of folks I've ever seen gathered in one building.
Precisely why I moved out of Mt. Juliet 35 years ago- - - -Wilson County got all yuppie-fied way back then! Nothing like the place I graduated back in 1963!
Jerry
I have had similar mystery issues with my 1998 Silverado when ANY aftermarket electronic parts have been installed. Usually means a day of aggravation and trips to return chit... 432,000 miles running on GM parts. If it craps out tomorrow I got my money’s worth. 50,000 miles on a new crate motor and trans, not rebuilds. Like a Rock....
It's either the points or the condenser,
What else could it be?
We could open a shop together!
We specialize in points and condenser work !
Should give us plenty of time to play cards and get a lil buzz on after a 12 pack
Yep, points and a condenser. Any one here remember how to "flash" a generator? If you don't, they will not work. learning the new ones, much more a PIA then the old ones were.
The last Chevy I'd want to own was built in 1972.
The last Chevy I'd want to own was built in 1972.
It was a very good year.
I live in Lafayette, but the closest DMV is in Gallatin. The most anal retentive bunch of folks I've ever seen gathered in one building.
Precisely why I moved out of Mt. Juliet 35 years ago- - - -Wilson County got all yuppie-fied way back then! Nothing like the place I graduated back in 1963!
Jerry
You certainly wouldn't recognize it today.