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Discussion Starter · #1 · (Edited)
2004 Sonata GLS 2.7 6cyl. Mfg. late 2003. Vin# KMHWF35H14A919865. Seems to have all electrical relays and components in different places than Forums and Manuals for like cars. Need to find location of ECM and Engine Control Relay. Have checked under hood, taken lower dash out on both sides, center radio and shifter console taken out. Nothing! Have wiring diagram that shows the car has them. Either it's not getting Ground to circuit of coil and relay, or bad relay, or I'm stumped. Also checked relay box behind interior fuse box. Not there or none bad. Have tested every relay I can find with no fails. Also new coil and Crank Position Sensor.
 

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I assume your trying to diagnose a non start here? The engine will crank but not fire?
Is the engine check light coming on when you switch the ignition on? Have you checked for spark? Does the fuel pump switch on DURING CRANK?

Sounds like you suspect there is a problem with the engine control relay. The fuses highlighted on the image below are supplied with power from the engine control relay, so take your voltmeter and check to see if they all have 12V when the ignition is switched on. If they do, you can feel pretty confident that the engine control relay is working.




Fuel Pump Test Point - Check Terminal Has 9~10V During Crank

 

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2004 Sonata GLS 2.7 6cyl. Mfg. late 2003. Vin# KMHWF35H14A919865. Seems to have all electrical relays and components in different places than Forums and Manuals for like cars. Need to find location of ECM and Engine Control Relay. Have checked under hood, taken lower dash out on both sides, center radio and shifter console taken out. Nothing! Have wiring diagram that shows the car has them. Either it's not getting Ground to circuit of coil and relay, or bad relay, or I'm stumped. Also checked relay box behind interior fuse box. Not there or none bad. Have tested every relay I can find with no fails. Also new coil and Crank Position Sensor.
Best practices for requesting help:


Be sure you are in the correct forum for your vehicle.
Give the model year....vin number can be very helpful.
Describe the problem the best you can.
Tell us what has been tried, if anything.
If the vehicle has been to a repair facility it would be nice if you can scan or take picture of the bill and attach it to the post.


This information can save a lot of time and get you the answers you need much faster.
You did OK except you didn't explain the actual problem. Autospark and others have to assume what the problem is.
 

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Discussion Starter · #4 · (Edited)
Yeah thought I had put enough information out there. Will Not Start. New fuel pump, coil and Crank Position sensor. Getting plenty of fuel to injector rails. No fire to Spark Plugs. All fuses under hood have 12v on one side whether Ign. switch is on or not. Checked all fuses inside and out.
Back to original question..... Where is the ECM and Engine Control Relay located on this particular car? All this started with car dying after idle for few minutes. Cranked it and moved into Garage to work on, and never cranked again. Have had a scan, No fault codes, Historic or otherwise. Has not been to Shop, since would need to have towed to another Town. Trying to save myself hundreds of dollars. If everything on the car works but cranking, seems like I should be able to figure out with some help and get running.
 

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Discussion Starter · #5 ·
Also, when ignition switch is turned on, you can hear the fuel pump running for about 5-10 seconds and stops. When line was loose to injector rail, pump ran as long as key was on because had no back pressure. So if CPS was bad, Fuel pump would not work, correct?
 

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Also, when ignition switch is turned on, you can hear the fuel pump running for about 5-10 seconds and stops. When line was loose to injector rail, pump ran as long as key was on because had no back pressure. So if CPS was bad, Fuel pump would not work, correct?
NO...the pump should run for a couple seconds on initial key up. When the key goes form EOEO (key on engine off) to KOER (key on engine running) the crank signal is what keeps the pump relay grounded. If the crank signal is missing the PCM will stop ground to the relay.
 

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All fuses under hood have 12v on one side whether Ign. switch is on or not.
The good fuses will have 12V on both sides. Blown fuses will have 12V on one side. But some of the fuses should have nothing on either side when the ignition is off.

royrokit said:
Back to original question..... Where is the ECM and Engine Control Relay located on this particular car?
The engine control relay "should" be behind the heater control panel. The ECM should be on the floor behind the center of the dash....see below.

But I think your getting a bit ahead of yourself. Where those parts are isn't really that important at this point because it doesn't sound like you've done enough testing yet to know if that is where the fault lies.

royrokit said:
Cranked it and moved into Garage to work on, and never cranked again.....everything on the car works but cranking
I assume your just getting your terminology mixed up here? The engine is actually cranking over when you turn the key to the start position....right?
So you have a crank but non start fault? Rather than a non crank?. It's important that we know exactly what the problem is because the approach to diagnosing both is very different.

royrokit said:
So if CPS was bad, Fuel pump would not work, correct?
Incorrect!

It's important to check that the fuel pump is being switched on during crank (see fuel pump test in my last post). The ECM switches the pump on briefly when you first switch the ignition on to prime the fuel rail. Generally, just for a couple of seconds then it will switch the pump back off. When you crank the engine over the ECM sees a signal from the CPS and it's that signal that tells the ECM that the engine is turning over. The ECM will then switch the fuel pump back on and start firing the injectors and ignition coils to make the engine run. But no CPS signal, no fuel (and generally, no spark either).

So, if it was me trying to diagnose why the engine wont run I would :
Check that the CEL is illuminating when the ignition is on.
Check for spark at the plugs.
Check for voltage on the pump test connector DURING CRANK.
Check the power supply to those three fuses I highlighted before.

If the CEL is illuminating,
and those three fuse have a good 12V supply (and they aren't blown),
but you find you have no spark and no voltage on the pump test connector DURING CRANK,
you are almost certainly looking at a CPS signal problem.

Sorry for the long post. I hope you managed to stick with it 'til the end :smile:

Let us know how you get on with that lot and we can decide where to go next.

 

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@AUTOSPARK has it right. Don't get the cart before the horse. Do what he asks about.....cranks but don't start or does not crank. Start there.
 

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Discussion Starter · #9 ·
Yeah I posted that it cranks but does not start. C106 and 107 does not represent where my fuel pump relay and engine control relay is located. Had all the dash apart and there are no relays or anything else in the radio/heater panel area. Have not checked the pump test connector. On the fuses under the hood. All fuses in that box have 12v to one side with the switch off. Have not pulled fuses when ignition is on to see if there is 12v on both sides but doesn't seem like that should be. Like I said, stumped. Will do more testing today. No blown fuses
 

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Quick check....... reach up in behind starter and verify CKP pigtail not all broken / crumbled... short of internal 3 wire in pigtail will knock out fuse and shut the works down
 

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On the fuses under the hood. All fuses in that box have 12v to one side with the switch off. Have not pulled fuses when ignition is on to see if there is 12v on both sides but doesn't seem like that should be. Like I said, stumped. Will do more testing today. No blown fuses
With respect, it doesn't sound to me like your testing your fuses properly.

If you look closely at the fuses you will hopefully see that each one has two little metal tabs on top. To test the fuses, connect your black voltmeter probe to battery negative. Now touch the red probe to battery positive and confirm you get 12V on the meter. This step is just to confirm the black probe is making a good connection to ground. Now switch the ignition on and touch the red probe to the two metal tabs on top of each fuse (just check them all). Confirm you get the same voltage on both tabs of each fuse. If you get a different voltage on one tab to the other, the fuse is blown. Pay close attention to the three fuses I highlighted before. If those three fuses have 12V you know the engine control relay is switched on. There isn't any need to pull fuses from the box...unless they're blown, of course.
 

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Discussion Starter · #12 ·
Yeah as I said, Replaced the CPS but it was about six months ago. At that time, the old one had frayed wires. Checked that yesterday and made sure CPS was still bolted good, but I know that it could have gone bad in the last six months. Checked resistance on CPS and it measured little better than 8ohms. Going to get back to it tomorrow with more testing. Will advise. Had and have no blown fuses. Only fuses in box under hood that don't have constant 12v to one side is the four spares. The CEL is illuminating when the ignition is on. Checked fire to plug from coil and there is none. I appreciate you taking the time to help me with this. I'll try everything you post and hope I find the problem. With everything else on the car working, I'm feeling more like it's the CPS but I'm all for testing everything. For the life of me, I cannot understand why relays and other things are in a different location than all the literature says that they should be. New coil two days ago. Not that it was bad, but the connector was all broken and messed up, so I felt better to change. Guess I could have gotten a new harness for it, but at 27.00, it made more sense to get a new one. Trying to give you everything I can think of. I'm not ASE (?) mechanic, but pretty good at it in general, so I'm not at a complete loss of knowledge when it comes to cars, but in this case, not too smart either.
 

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Only fuses in box under hood that don't have constant 12v to one side is the four spares.
So you have constant 12V being supplied to the ignition coils, fuel injectors and engine sensors too?

I guess you must have since they are all supplied with power from the fuses on the engine bay fusebox. Sounds like you have deeper issues to deal with than a simple non start.
 

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The Cam position sensor will cause the same problem, right?
What problem?

royrokit said:
If they are not supposed to have constant power, what would cause that? Ignition switch?
Possibly. Or there could be a short circuit between a constant 12V circuit and one of the ignition circuits.

I assume your battery keeps going flat too? You must have quite a high parasitic drain on the battery with all those ignition circuits powered up all the time.
 

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Boy how we have muddied the waters on this one.
 
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