2003 engine starts when battery connected

[Stanley S.]

I replaced the battery on my 03 last week and after I connected the positive cable to the battery first and then the negative, the engine started, ran for about 5-10 seconds, then stopped. It repeated this cycle for 3 times before finally stopping for good. All of this happened without the key in the ignition. This was a little unnerving. Has anyone else ever had this experience before? Thanks.


Stan

[Edward J.]

Re: 2003 engine starts when battery connected

Stanley, is it possible that some one installed a remote starter? This is common with cars with remote starter when re-hooking the battery.

[Michael J.]

Re: 2003 engine starts when battery connected

I have had this happen on old cars, with a failed starter solenoid that stuck closed and the key had no effect on it. But after it started, did the starter stay engaged and spinning, or did it disengage?

[Stanley S.]

Re: 2003 engine starts when battery connected

Michael -- The starter disengaged as soon as the engine started as it would upon normal key initiated starting. What was really spooky was how the engine went through this start, run, stop sequence 3 times before finally stopping.

Stan

[Stanley S.]

Re: 2003 engine starts when battery connected

Edward -- I suppose a remote starter is possible (the car has had 2 owners prior to myself). Where do you suppose the control box would be installed in the car?

Stan

[Edward J.]

Re: 2003 engine starts when battery connected

Stan , generally under dash the should be a control unit tied up or tucked up somewhere. and sometimes you may see a deactivation switch.

[Mike E.]

Re: 2003 engine starts when battery connected

Had the same experience with a 2001 Suburban. No remote start. Hooked up the battery and it suddenly started. But only once. The keys were NOT in the ignition, and this was pre-fob days.

[Stanley S.]

Re: 2003 engine starts when battery connected

Thanks everyone for your comments. I looked under the dash after taking loose a cover and can't see any sign of a remote start control box but I suppose I could be missing it. I may give my local dealer a chance to figure this out.

[Richard M.]

Re: 2003 engine starts when battery connected

Very strange issue. Curiously I looked for some electrical data to see if there is a separate starter Relay involved in the Starter circuit. I am not sure if a Relay exists between the key and the Starter Solenoid, but if so, that would be my first place to be a suspect. Maybe a week relay contact spring of intermittent relay coil or similar oddity.

I found a detailed description of the 2003 Starter Operation at the GMheritage Center AMA Spec page, but no confirmed relay usage....

https://www.gmheritagecenter.com/docs/gm-heritage-archive/vehicle-information-kits/Corvette/2003-Chevrolet-Corvette.pdf

Page 61/62 gives a very detailed description of the circuit, but mentions NO starter relay, just the key and solenoid. The starter motor itself, a Type PG260L, is mentioned as "Non-Repairable" though. Maybe that is the smoking gun.

A detailed wiring diagram would help a troubleshooting exercise to understand the actual path of the circuit. The Ignition switch may be a direct path to the solenoid, but I have a gut feel it does not, and likely passes through some digital logic and on board relays to energize the starter. If anything, maybe through either the ECM Engine control or the BCM Body Control Modules.

I'd certainly be curious as to what you discover. I would be very concerned if this is a Manual Transmission car, and if it turns out to be a Digital Circuit fault, I would ensure that you keep your Park Brake engaged at all times until you get it diagnosed. If a self start occured in Gear due to additional Digital device anomalies, it could be very dangerous.

Rich
p.s. Sorry if I appear paranoid but I am a past electronics engineer and I've seen some pretty unusual failures in my time and have a serious concern for safety when relying on digital electronics to do everything these days. Certain failure types can create safety issues. Today, everything is "Fly-By-Wire". Every time I fly commercially as a passenger I always hope that the folks that designed those teeny-tiny digital circuits like I used to for the computer and networking world, have several built-in backup logic circuits to take over if needed. For those of you who professionally fly those big jets,(Mark D. I know you're one of them) you know more than I do for sure.

Case in point.....Last Sunday while returning from Lakeland FL in my truck towing my trailer, and my wife following along behind me in my '07 Corvette, a simple rest stop turned into a near flat-bedded nightmare.

After the stop, the Auto Transmission shift lever was jammed. It could not be shifted to Reverse or Park. Only Drive and Neutral. I tried feverishly to get the shifter to go into reverse. She parked up close to another car and couldn't move forward. Finally the car in front left and we were on our way back home, but feared a need to shift to reverse if needed. This only about 20 minutes from home, but the scary thought was were were nearly 3 hours from home in Lakeland. If it happened then, after about 50 shifts while there, it would have been a real PITA.

When time allowed, I discovered the fault a few days later after tearing the entire console and shifter apart. The Shift Interlock circuit and the shifter lock solenoid, controlled by a negative pulse from the RCDLR (The remote control door lock receiver module), then to a relay in the fuse center inside the car behind the passenger foot panel floor cover, was at fault. I did a quick relay swap but no go. I then had to use my OBDII diagnostic scanner to run through some tests to eliminate the RCDLR digital logic controller. After that I was able to decipher the fault and it turned out to be a simple problem. The internal interlock lever had jammed into it's locking cam. A simple "POP" of it with a pair of pliers freed it.

Before putting it all back together, I decided to create a on board failsafe if it ever happens again. I added a emergency release cable to the mechanism and ran the cable into the center console. One little yank on the cable and it can shift even if the battery is dead. A funny "bubba" cable to overide such fancy sophisticated electronics. But as the Chief of Police on Amity Island said after the first time with that "Great White" in Jaws II.........."I'm NEVER gonna let that happen to me AGAIN"!

===

[Rich G.]

Re: 2003 engine starts when battery connected

Rich and I have more than our names in common. Having been involved in circuit design as an engineer and finally engineering and software management I'm really glad we weren't designing circuits for cars and airplanes. I would be afraid of that car until I knew what was wrong and it was fixed.

Rich (the other one)

[Terry M.]

Re: 2003 engine starts when battery connected

Very strange issue. Curiously I looked for some electrical data to see if there is a separate starter Relay involved in the Starter circuit. I am not sure if a Relay exists between the key and the Starter Solenoid, but if so, that would be my first place to be a suspect. Maybe a week relay contact spring of intermittent relay coil or similar oddity.

I found a detailed description of the 2003 Starter Operation at the GMheritage Center AMA Spec page, but no confirmed relay usage....

https://www.gmheritagecenter.com/docs/gm-heritage-archive/vehicle-information-kits/Corvette/2003-Chevrolet-Corvette.pdf

Page 61/62 gives a very detailed description of the circuit, but mentions NO starter relay, just the key and solenoid. The starter motor itself, a Type PG260L, is mentioned as "Non-Repairable" though. Maybe that is the smoking gun.

A detailed wiring diagram would help a troubleshooting exercise to understand the actual path of the circuit. The Ignition switch may be a direct path to the solenoid, but I have a gut feel it does not, and likely passes through some digital logic and on board relays to energize the starter. If anything, maybe through either the ECM Engine control or the BCM Body Control Modules.

I'd certainly be curious as to what you discover. I would be very concerned if this is a Manual Transmission car, and if it turns out to be a Digital Circuit fault, I would ensure that you keep your Park Brake engaged at all times until you get it diagnosed. If a self start occured in Gear due to additional Digital device anomalies, it could be very dangerous.

Rich
p.s. Sorry if I appear paranoid but I am a past electronics engineer and I've seen some pretty unusual failures in my time and have a serious concern for safety when relying on digital electronics to do everything these days. Certain failure types can create safety issues. Today, everything is "Fly-By-Wire". Every time I fly commercially as a passenger I always hope that the folks that designed those teeny-tiny digital circuits like I used to for the computer and networking world, have several built-in backup logic circuits to take over if needed. For those of you who professionally fly those big jets,(Mark D. I know you're one of them) you know more than I do for sure.

Case in point.....Last Sunday while returning from Lakeland FL in my truck towing my trailer, and my wife following along behind me in my '07 Corvette, a simple rest stop turned into a near flat-bedded nightmare.

After the stop, the Auto Transmission shift lever was jammed. It could not be shifted to Reverse or Park. Only Drive and Neutral. I tried feverishly to get the shifter to go into reverse. She parked up close to another car and couldn't move forward. Finally the car in front left and we were on our way back home, but feared a need to shift to reverse if needed. This only about 20 minutes from home, but the scary thought was were were nearly 3 hours from home in Lakeland. If it happened then, after about 50 shifts while there, it would have been a real PITA.

When time allowed, I discovered the fault a few days later after tearing the entire console and shifter apart. The Shift Interlock circuit and the shifter lock solenoid, controlled by a negative pulse from the RCDLR (The remote control door lock receiver module), then to a relay in the fuse center inside the car behind the passenger foot panel floor cover, was at fault. I did a quick relay swap but no go. I then had to use my OBDII diagnostic scanner to run through some tests to eliminate the RCDLR digital logic controller. After that I was able to decipher the fault and it turned out to be a simple problem. The internal interlock lever had jammed into it's locking cam. A simple "POP" of it with a pair of pliers freed it.

Before putting it all back together, I decided to create a on board failsafe if it ever happens again. I added a emergency release cable to the mechanism and ran the cable into the center console. One little yank on the cable and it can shift even if the battery is dead. A funny "bubba" cable to overide such fancy sophisticated electronics. But as the Chief of Police on Amity Island said after the first time with that "Great White" in Jaws II.........."I'm NEVER gonna let that happen to me AGAIN"!

===

Rich M
I am impressed (very) with your diagnostic skills. All too often now days people will replace components until hey cure the problem, and never know the root cause. Systematic diagnosis is all too rare now days and you excel at it. Great job. You set a fine example for the rest of us who want to know "what makes it tick."

[John D.]

Re: 2003 engine starts when battery connected

FWIW here's the starter schematics....

[Richard M.]

Re: 2003 engine starts when battery connected

Rich M
I am impressed (very) with your diagnostic skills. All too often now days people will replace components until hey cure the problem, and never know the root cause. Systematic diagnosis is all too rare now days and you excel at it. Great job. You set a fine example for the rest of us who want to know "what makes it tick."

Thanks Terry.

I read about some folks who had the entire shifter changed at very high cost, some over $500. The solenoid is riveted to the shifter side and is not a "replaceable" part. I wonder how many that were replaced had the same problem as mine. It was tricky to see, until I removed the top section where the boot connects. Then I could see the stuck cam easily. Solenoids are rare to fail. Simple coil and plunger. One side of the coil is constant 12V, the other side is the switched ground from the RCDLR. I tested the solenoid with some jumper wires with it's 2-pin plug disconnected from the harness. It worked fine. That's when I found the stuck lever.

FWIW here's the starter schematics....

John, Perfect! Thanks....Nice find.

"Theft Deterrent" Relay controlled by the BCM. The feed to the Starter (up to the TD relay) is always Hot. If the BCM logic is confused and results in a logic-zero when the battery is connected, that supplies the negative side of the Theft Relay coil and possibly could energize the TD Relay and crank the starter.

[Philip A.]

Re: 2003 engine starts when battery connected

Rich and I have more than our names in common. Having been involved in circuit design as an engineer and finally engineering and software management I'm really glad we weren't designing circuits for cars and airplanes. I would be afraid of that car until I knew what was wrong and it was fixed.

Rich (the other one)

My concern is often not in the design but with the manufacturing quality/composition/precision/tolerances (not meeting specification) which is typically where the failure lies and then blamed on the design.

[Rich G.]

Re: 2003 engine starts when battery connected

My concern is often not in the design but with the manufacturing quality/composition/precision/tolerances (not meeting specification) which is typically where the failure lies and then blamed on the design.

On the other hand there is the famous developer line used by both hardware and software engineers: "jeez, it never did THAT before." :-)

Rich G