Ok guys I'm starting to regret buying this car and really am growing very impatient and fustrated at this point. Long story short.. I bought an 02 maxima Se MT for a good deal (well I thought).. when I bought the car it didn't start. The security light was on and car wouldn't turn over. Did some research.. was thinking the keys needed to be reprogrammed to the car but come to find out the issue is much more serious than that...

So took the car to dealership and they said the ECM was bad and may need a wiring harness as well. Of course they wanted an arm and a leg to repair but even then they said it may and may not be the issues that caused the problem in the first place...

So I towed the car back home and started trouble shooting things myself. I sent my ECM off and got it fixed, I changed out the TB and did bypass. Heard from some that the TB can cause the issue with the ECM to malfunction. Reinstalled everything.. and still nothing. Also noticed that my CEL never comes on... I hooked up my odb scanner and it wouldn't connect. Tried another scanner and same thing. Both scanners wouldn't connect to the car. I'm thinking that the ECM isn't getting power. What all do I need to look at to start trying g to fix the issue. I checked all fuses and tested them and they were good... was thinking grounds aswell but where at or what all grounds should I look at?

I'm starting to run out of options and need help. Any advice would be greatly appreciated. Also please keep in mind I'm not a certified mechanic. I'm an average guy that knows alil bit bout cars and stuff so don't beat me up to bad if I don't know what yall are referring too lol.

 

The ecm gets power on 3 pins. Pin 67 is live all the time from fuse # 59. Fuse # 59 is under the hood in the box by the battery. The cover label is (you're gonna love this) SPEAKER.

The other 2 pins are 110 and 112. These 2 pins will have power when the ignition switch is in the ON position.

See page 139 in the link below for the ECM connector pin numbering and other pin signals.
link - http://boredmder.com/FSMs/Nissan/Maxima/2002/EC.pdf

FWIW the NATS security does not disable the starter, the engine will crank. The ECM does not play a part in the starter circuit either. Even with a bad ECM, the starter will crank the engine.

If somebody tried to put a third party alarm/remote starter in or took one out, you do have problems. Look up under the dash between the steering column and the fuse panel and see if any wiring looks out of place, like spliced wires, loose wires, wires not in a harness, etc.

 

I will recheck the fuses again. And wow under speaker? Lol I wonder if that could be an issues seeing that the radio is out of the car? No radio was in the car when k bought it. But yes the car cranks just doesn't turn over and run. I tested the voltage on the injectors to see if they were working... it read around 8v when I turn the ignition when priming then nothing after. So leads me to believe the ECM isn't powering on or sending signal. But again let me check the pins and fuse and go from there.

 

You can and should check the fuse, but you need to get your voltmeter and check and see if you have 12 volts on the ECM pins. You could have good fuses but a broken wire will screw you.

As far as the radio being removed, that won't make any difference. The radio is a user of the power, it gets it from the fuse. Secondly, the power from the fuse goes to the amplifier in the trunk, not the head unit in the dash.

 

Well... found the problem.. now how to fix it? After testing all power supply, grounds and fuses come to find out there is a short some where between the ECM relay and the ECM itself. I finally got a CEL light after jumping/bridging a wire from one side of the relay to the next. As described in the pic. Is there a way to fix it? Could I rig it up somehow to run like that? Or will I need a new harness? Also I didn't bridge the other wire that connects to ECM that is the Counter current return to ECM. That isn't getting power either? Didn't know if I should do that aswell. I swapped a relay out on it to see if it was a bad relay but it didn't change anything.

Also my security light isn't on anymor

 

Hopefully you have found the problem area. It seems that you are on the right track. But there are still some other things to check. Maybe you did, but you just didn't mention it.

That relay gets power from 2 different fuses. They are in the fuse box by the battery with the labels of ENG CONT 1 and ENG CONT 2. Hopefully you checked both these fuses. Also - did you check the fuse for the power that goes to pin 43 of the ECM? It plays an important part for the relay you were checking. It has the label FL40A IGN SW.

We know fuse # 59 is good because of the jumper you put on it. That jumper also makes it seem like the relay is maybe bad. So you swapped the relay with another one. There are 3 or 4 different relays used. Some will not plug in, while others will but the contacts inside are different. I hope you used the relay next to it or above it because they are the same.

Assuming you used the correct type of relay and that did not change anything, that sounds like the relay is not being told to energize to close the contacts inside. So we have to check that out. Fuse # 58 is used for energizing the relay.

Before I go any further, I need to know if you have either a voltmeter or a test light. You will not be able to do any of the checking that needs to be done and it would be useless for me to go on. Please let me know.

Let me answer the questions you asked. As for the jumper you put on, you do not want to leave it on all the time. The ECM would eventually drain the battery. Do you need to replace the wire harness? At this point I have no idea. Do you see wires that are chopped up and cut and no longer connected? If that is the case, then maybe you should, especially if it is a lot of wires.

But there is one more jumper that you can try. This would be to energize the ECM relay. Get it wrong and you will blow fuse # 58. Connect a jumper from pin 1 of the relay to ground. The wire on pin 1 is white with a red stripe. This will make the relay energize and close both connection inside it. Try starting the car. Again, don't leave this jumper on permanently as it will drain the battery.

 

Dennis I'm using a voltmeter to do my checks. I did check the fuses on ENG CONT 1 AND ENG CONT 2... and also checked the fuse for pin #43 it was good aswell.. reading around 11.4v. And yes I swapped the relay with the one above it. And it still doing the same thing. I don't see any wires that are cut or spliced. I did notice that the camshaft position sensor connecter is alil loose.. but nothing else.

I haven't tried jumping pin #1 to ground on relay yet, but will try that next to see what it does.

Also now that I have the CEL on I'm getting 3 codes. P0340, P0345, and P0113. Two seem to be related to the Camshaft position sensor and the other to the MAF. Not sure if that what not letting the car start.

 

Those 3 codes may be normal under the circumstances. Right now, the ECM relay is not engerizing and the camshaft sensors (codes P0340 & P0345) get their power from the ECM relay. See pages 337 & 338 in that link I gave you.

The same idea goes for the P0113 code. The IAT (Intake Air Temperature) sensor that is part of the MAF, gets its power from the ECM. See page 202. So if the relay is not energizing and sending power to the ECM, I suppose the code is to be expected.

So we have to figure out why the ECM relay is not energizing. For starters, check the voltage on the wire that will energize the ECM relay. Check at the ECM connector, pin 38. Before you turn the ignition key on, check the voltage. It should be close to 12 volts. Now turn the ignition key on. The ECM will essentially ground this pin and there will be less than one volt when the relay is energized. If you are getting a voltage reading of something like 11 - 12 volts, the ECM is not trying to energizing to energizing.

If you are getting a zero/almost zero reading, the check the wire at the relay. This is pin 1 of the relay and has a white with red stripe wire on it. If you have zero volts at the ECM and approx 12 volts at the relay, you have a broken wire from the ECM.

If you have zero volts at pin 1, the relay should be energized and there should be 12 volts going to the ECM on pins 31, 110 and 112. Check for this, don't assume this is happening.

 

Dennis just got out here and messed with it since all this snow and work. Did that last jumper wire check on pin 1 of the ECM relay and it started the car. Now... Once I take the wire off ground it kills it. I traced that wire down from F18 connector and it goes from W/R to a W/B wire AMD there was a short in it.. Or should I say that the wire was burned up and snapped. I rewired it and tried but still nothing. It will start with me jumping the ground on pin 1 of relay. Also checked every wire that goes to that connector up to about where the intake manifold is on the left side of motor and they all check out.

... Question tho... Since grounding that wire off relay closes the relay could I hook up a switch to use it while the car is running then shut it off while the car is off?.. That shouldn't kill the battery should it?

 

Do you live in the area that got the blizzard over the weekend? You poor guy.

Anyway...

Technically speaking, you don't have a short in the wire to pin 1 of the relay. Technically speaking, you created a short when you added the jumper. A short and an open are opposites.

I would suggest you check the continuity of the wire in the harness that goes to pin 1 of the relay. Check the wire between the relay pin 1 and the ECM pin 38.

If there is no connection, then we'll have to go to the E15/F18 connector that is in between the ECM and the relay and check each half of the wire.

In that link I posted back in post # 2, connector E15 is on page EL-460 and connector F18 is on page EL-464.

 

Lol sry I just seen your post as I edited mine. Yes I checked both sides of the connector F18 didn't check E15. Will have to check it in the morning.

 

To us common people, we see E15 and F18 and think these are 2 completely ddifferent things. They are the same connection and to my thinking they should both be number 15. But I'm not Nissan.

When you say you checked both sides of E15, I think that you did check F18 also as E15 plugs into F18. I still think you should check the full wire run from the ECM to the relay.

I don't see any problem with you using a jumper wire with a switch in the line. If you were to forget to flip the switch when you park the car, it would take a good while to completely drain the battery. I don't know how long it would take, but the relay coil doesn't take that much power and you might even be able to start the car in the morning.

 

I don't think I had the same problem as you, but I also had a problem with the ecu getting power from the relay. Here is my thread if any of it could be helpful to you
https://maxima.org/forums/5th-genera...-not-work.html