[Moose12!]

Here gose I have 2004 V6 Tib that has now died completely and will not start.
It was having and intermittent starring problem, if you turned the key on and the check engine light was light you could crank it and it would start and run fine for minutes or maybe days.
Now no check engine light when key on crank with no start.
I inspected the CPS it did not look new so I replaced it with an OEM part no change.
No power to injection or snsr fuse ??
So a bunch of sensors have no ect ect
Jump the main power relay get power to the fuses but no crank.
What controls that main power relay?
Any thought about what could be causing this issue??
Thanks Steve

 

[aveenav]

when was the timing belt last changed?

 

[The_Evenger]

wait, no CEL when the key is on? first, verify that the bulb isn't burnt out (only bulbs in the gauge cluster are the CEL, low oil pressure, and AIR BAG lights.)

once you've done that, check power and ground feeds to the ECU.

no CEL with the engine off would indicate that the ECU is not powering up.

 

[Moose12!]

Can anyone help with the pin out info for testing the ECU plug?
Thanks Steve

 

[Charlie-III]

Can anyone help with the pin out info for testing the ECU plug?
Thanks Steve

Online PDF manual is here.....Hyundai Coupe Gen 3 / 3.5 / SIII (GK / GK FL / GK F/L2) Workshop Manual
There is also a manual download on this site, go to some of the later links as it has changed hosting sites over the years.

 

[Moose12!]

Ok so after testing the power and grounds at the ECU and a few other circuits looks to me like the ECU is not waking up when powered up.
So if I get a used ECU will it be a plug and play or will need special programming?
Thanks Steve

 

[dmdicks]

Have you checked for power at the ECU fuses? Its VERY rare to have an ECU fry and typically if one does its due to some sort of short in the wiring harness so a new/used one will just fry until you fix the issue.

Check your fuses inside and outside the cabin, and check for any frayed wires around all sensors.

If everything looks good then you can pick up a used ECU just make sure its for the same year and transmission that you have. If its an early Tiburon made in 02 then it takes a different ECU then ones made in later 02. Also if where you live requires a VIN check during emissions you will fail with a used ECU because it will have a different VIN.

 

[Moose12!]

No power on the ECU fuse or injector fuse as the ECU is not sending out a negative to pull in the main relay.
Thanks

 

[dmdicks]

check all the connections in the engine bay relay box. Unbolt it from the fender and remove the bottom to access all the connections.

 

[Moose12!]

Here's an update
Used ECU , plug and play starts and runs fine.
Now have a P1602 code for some reason??
Transmission communication error.
Any thoughts on this code, I can clear it but it come back on after start up.
Thanks Steve

 

[The_Evenger]

p1602: Engine Control Module Supply Voltage Low From Battery

from what I've read, the ECU will measure voltage from different points and throws this code if it finds a difference.

it looks like there's an ECU fuse that handles memory power, and an ECU fusable link that handles key-on power. I would start by measuring voltage at each power feed and chase whichever one is low, provided one is low.

keep in mind, a bad ground can also cause voltage to go up.

 

[dmdicks]

Did you put an automatic ecu in a manual car?