Tech question 2007 Hyundai Sonata

Outlaw

Well-known member
Joined
Jul 24, 2009
Messages
15,635
Reaction score
8
Location
Johnsburg
I picked up a 2007 Hyundai Sonata yesterday supposedly needing a fuel pump. Car was owned by a friends uncle. Was told his daughter was driving it, it shut off, was towed to a repair shop where he was told it needed a fuel pump. He decided to just sell it as is for pennies as it was a spare spare car and not needed. Of course it's never that easy. Replaced the pump still nothing.

Things I have done/tested with power probe.

-Replaced fuel pump.
-Checked continuity from power wire from pump to relay. good.
-Checked continuity from ground wire from pump. good.
-Checked relay and fuse for fuel pump. both good.
-Checked continuity from relay to ECU both pos and neg. good.
-If I put 12v to the fuel pump from the relay location with my power probe, the pump will turn on and the car will start.


Fuel pump is 4 post relay. I receive good power TO the relay from the battery, but when ignition on I only receive 2.5v from the ECU signal wire. I checked continuity as I said so I can reasonably eliminate any issues with the wiring to the ECU.

Next logical thing (in my mind) would be ECU is bad, yes? As far as I was told, the car was driving just fine and simply shut off. Also, if I buy a used ECU, what's it take to program it IF that is needed? I get conflicting answers on brand specific forums...

I feel like I'm at the point of having to "throw parts" at the car which I've never been a big believer in, an ECU also isn't a spark plug, and it's an expensive part to throw at the car if that's the route I need to take. Is anyone on here a tech/have access to AllData schematics for the wiring between the ECU and fuse block and any and all fuses that contribute to the ECU? Any help is appreciated!
 

bikrboy128

Some say.....
Joined
Jul 15, 2007
Messages
10,652
Reaction score
57
Location
Wheaton
07 with a 3.3 i assume?
looking at this, i'd be looking at the ECU fusible link/engine control relay
the two blue wires (14 off the junction block) go to the upstream O2 sensors. maybe one of those is feeding back?
 

Outlaw

Well-known member
Joined
Jul 24, 2009
Messages
15,635
Reaction score
8
Location
Johnsburg
3.3 yep!

I’ll look at this in the AM but this diagram is helpful, I couldn’t find anything worth a shit via google
 

Outlaw

Well-known member
Joined
Jul 24, 2009
Messages
15,635
Reaction score
8
Location
Johnsburg
FWIW it also had these codes when I got it to start, granted the level sensor and pressure sensor weren’t plugged in at the time of start up and read as well

Po105
Po452
P0037
P0057
P0160
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Top Bottom