Weird CEL after a bump start

[guybo]

At work I park on a bit of a slope. Friday I rolled back and bump started my car (MT of course) just for shits and grins. It tripped a CEL P0616
Starter Relay Circuit Low.

I've bump started about 8000 manuals for other people, and in the past on my own cars it's a regular thing. This is the first I have ever seen a code thrown from it.

[steve99]

Originally Posted by guybo

At work I park on a bit of a slope. Friday I rolled back and bump started my car (MT of course) just for shits and grins. It tripped a CEL P0616
Starter Relay Circuit Low.

I've bump started about 8000 manuals for other people, and in the past on my own cars it's a regular thing. This is the first I have ever seen a code thrown from it.

id guess the battery was flat/low hence the bump start. It probably just tripped cels due low battery of fail to start when battery low.

clear the codes if they return then investigate further

[Ultramaroon]

Originally Posted by guybo

At work I park on a bit of a slope. Friday I rolled back and bump started my car (MT of course) just for shits and grins. It tripped a CEL P0616
Starter Relay Circuit Low.

I've bump started about 8000 manuals for other people, and in the past on my own cars it's a regular thing. This is the first I have ever seen a code thrown from it.

It would be low if you didn't use it.


Actually no idea. I've bumped mine many times like you, just for whatevs. Never thrown a code.

[guybo]

My car is brand new and the battery has never had an issue. I just thought it was weird that a bump start would tripa CEL. Has anyone else ever had this happen?

[steve99]

http://www.clubwrx.net/forums/genera...ml#post3859745

[guybo]

I have Torque Pro and turned it off once I found that the CEL disables cruise (annoying). I was going to leave it on just to see how long it'd take to turn itself off, but cruise control ont he way home is more important than curiosity.

It's not a huge deal just a weird one. Every car has its quirks and from that link it looks like that's a quirk of this car.

[Spartarus]

It should have gone out the next time you key-started the car. It's normal. I would post the appropriate section of the wiring diagram if I could snip on my phone.

In this car, the switched ground for the starter relay isn't switched directly by the key switch. It's switched by a circuit in the ECM, which is monitored for voltage. It will read 0v during a bump start since the circuit will be open.

The ECU sees 0v on the starter relay circuit during what it thinks is a cranking event, and voila, CEL.

In a normal world, one day when your car won't crank over, no more crawling around and knocking on solenoids with a screwdriver. Just read the code and replace the relay, or if the circuit volts read appropriately, replace the starter. Simpler diagnosis. That was the intention.

[guybo]

Thanks for the explanation! The starter is right there on top, if I ever have to do a starter tap it'll be easy. I don't think I've ever seen such a small starter before, it's like a toy. That said.... I have a MT that weighs less than 2800 lbs.... I could push start alone if I had to LOL.

[steve99]

Originally Posted by Spartarus

It should have gone out the next time you key-started the car. It's normal. I would post the appropriate section of the wiring diagram if I could snip on my phone.

In this car, the switched ground for the starter relay isn't switched directly by the key switch. It's switched by a circuit in the ECM, which is monitored for voltage. It will read 0v during a bump start since the circuit will be open.

The ECU sees 0v on the starter relay circuit during what it thinks is a cranking event, and voila, CEL.

In a normal world, one day when your car won't crank over, no more crawling around and knocking on solenoids with a screwdriver. Just read the code and replace the relay, or if the circuit volts read appropriately, replace the starter. Simpler diagnosis. That was the intention.

weird, ive clutch/bump started my car several times never thrown a CEL, also did it on car I test drove at dealer as I was curious to see if it would work.

[justatroll]

Originally Posted by steve99

weird, ive clutch/bump started my car several times never thrown a CEL, also did it on car I test drove at dealer as I was curious to see if it would work.

Sorry for the partial thread-jack but this is appropriate given your post:

Has anyone ever successfully bump started a MT BRZ with push button?

I have been wanting to try it just so I would know in an emergency.
Knowing in advance if it works would help in the decision to try it or not.

But now I dont feel like doing the experiment just for grins.

[steve99]

Originally Posted by justatroll

Sorry for the partial thread-jack but this is appropriate given your post:

Has anyone ever successfully bump started a MT BRZ with push button?

I have been wanting to try it just so I would know in an emergency.
Knowing in advance if it works would help in the decision to try it or not.

But now I dont feel like doing the experiment just for grins.

Believe it or not i bump\clutch started a brz on my fisrt test drive just to prove it would work, dealer though i was an idiot.

to bump start with push button
1. Without pushing clutch in , press start button twice to put ignition full on
2. Now depress clutch, select second gear (find it better than 1st)
3. Push or roll car, release clutch fairly quickly, depress clutch again once started


done it a few times, never a cel

[Ultramaroon]

Originally Posted by Spartarus

It's normal...<snipped>

The ECU sees 0v on the starter relay circuit during what it thinks is a cranking event, and voila, CEL.

If I understand your point, the CEL should occur at every bump start. This is not my experience. I've bumped mine many times.

It makes sense, hence my first tongue-in-cheek remark but I think there's more to it.

[Spartarus]

I've only bump started once. Got the same P0616. Looked at the wiring diagram and found out why.

It's interesting to hear that it apparently doesn't happen every time.

Difference between this car and older cars is the circuit that grounds the starter relay is not switched by the key, its switched by the ECM.

I didn't write the code that trips the CEL, and given the usual habits of OEM's I'm sure the logic is quite complex.

There could be many reasons it doesn't trip every time.

It may only trip under specific circumstances. If anybody cares enough to get on a hill and figure out the logic, go ahead.

[steve99]

Originally Posted by Spartarus

I've only bump started once. Got the same P0616. Looked at the wiring diagram and found out why.

It's interesting to hear that it apparently doesn't happen every time.

Difference between this car and older cars is the circuit that grounds the starter relay is not switched by the key, its switched by the ECM.

I didn't write the code that trips the CEL, and given the usual habits of OEM's I'm sure the logic is quite complex.

There could be many reasons it doesn't trip every time.

It may only trip under specific circumstances. If anybody cares enough to get on a hill and figure out the logic, go ahead.

Yes, their is quite likely code differences in ecu or wiring changes especially since I am in Oz. It might also be to do with sequence you use to bump start.


example we have no evap system here not even wiring to ecu.