PLEASE HELP! NEW ecu?!?

[440racer]

Long story with many SES codes

First off my 01 PF has about 163k miles on it now.

A year ago the SES light began coming on when it was cold & damp. I have to get the emissions checked every year in May so I had the codes areased and drove the car enough to reset the computer without throwing a code and was able to pass emissions.

This past winter when it started getting cold again, the light would come on and it was throwing all sorts of codes so I replaced the cam timing and position sensors and then started replacing coils (all aftermarket) and plugs.

After replacing 3 coils, I was still getting P1320 so I took it to Nissan for service. They said that it was a "primary ignition" code and since I had used aftermarket coils, I should have them replace all 6 coils at the same time.

I then replace the other 3 coils so all 6 are new. It was still throwing a p1320.

Then through some research I discovered that there is a way to check the coils to see if they're operating within range. This was beyond me so I took it to an independent who seemed to know how to diagnose the problem.

After a few hours the indie called ant told me I had a ignition relay that was bad and he would replace it. I told him o.k. and suggested he check the condenser as it was mentioned in the same thread that explained testing the coils. He later called and told me that the condenser was in fact bad and that the condenser had caused the relay to stick in the closed position and this had caused the ecu to go bad so that when the new relay was installed the truck would not start with a properly operating relay. So he told me that I need a new ecu.

I needed the truck today to pull my trailer for some work and asked him to re-install the old relay so that the truck would run and I could tow my trailer. He did so and the truck does run and I used it today.

I've spent a lot of money and time on a 10 tr old truck with 160k+ miles on it and don't really want to spend any more than I have to.

My question is: could a bad condenser cause a relay to go bad and stay in the closed position allowing the truck to run but throw the p1320 code? Also could these series of failures damage the ecu so that the truck would only run with a bad relay?

[Towncivilian]

Swap out the ignition relay with any known working blue relay (blower motor relay is right next to it, use that) and see if the engine runs. The relay is located behind the coin tray, it's the one on the far left. Or buy a new one if you want, or find one at a junkyard. I think your ECU is fine.

What "condenser" are you speaking of? I know of no such thing, other than the A/C condenser and its related components. Even a general search for "condenser" on Courtesy Parts yields only A/C parts. Maybe I'm having a brain fart here. Could you link to the thread you mention? Do you mean power transistor, possibly? EDIT: Looking at the FSM, there is indeed some "condenser" component. And the FSM says to check the ECM relay, not the "ignition" relay.

Unfortunately, 2001 model PFs commonly have issues with ignition coils. The 2001.5 revision have different coils as a result.

[440racer]

Towncivilian,

The thread that referenced the condenser/capacitor is http://x.nissanhelp.com/forums/maxima/9 ... -code.html. I've looked a lot of forums to try to fix the problem.

The tech may have said ecu relay and not ignition relay. He definitley said the part was bad and stuck in position (I assume closed) which allows the engine to run.

I will try the relay swap suggestion you offered.

The tech has replaced the condenser/capacitor I think it's taped up in the harness.

I'll repost after swaping relays.

Is there a solenoid in the ingnition system possibly and if so couls that be what he replaced?

[ARKQX33V6]

It's likely that a condenser can fail, but as Towncivilian has mentioned what condenser. The condenser for the A/C is a heat exchanger, where as the condenser used in conjunction with a relay is an electrical device that holds, squelches the DC current when a switch makes and usually breaks the circuit because DC does not want to break and stop flow.

The condenser for a relay in automotive would be at 12 V operation and the ECU is at 5 VDC. The ECU is robust on cars and trucks with failure to DC voltages by memory problems, breaking contacts that do not want to stop flow, by mishandling or ground problems. Of course there are more.

A relay may weld close and continue to conduct when the relay control has issued a stop condition or the relay is held open because the contact is broken, or the trigger mechanism has failed the relay and it is stuck open, closed or part way and depending on the problem any fusing may or may not come into play because of a no excessive loading but rather a conflict of what should be on or off at a certain time.

Getting into the head of a practitioner testing a circuit or a bunch of circuits as in a ECM is about impossible because of the lack of mind reading, but the logic can be examined and a possible yes or no or what?...Yes it is possible, but is it probable.?!.

You chose this person to deal with a particular problem and then you are curious about his answer, his expertise. This is usual from my experience based directly on the costs spent so far diagnosing the problem(s). Some things are not simple to fix because there is simply too much, too many thing that can go wrong and when that happens the fixer feels... replace. With my experiences many guy fix by replacing parts because they do not know how to troubleshoot. The world of fix is wrought with many of these types because the art of learning the correct way is too long, too expensive and in fact we are a throw away world.

I understand your predicament and wish you well.

[Towncivilian]

440racer, I highly suggest attempting to follow the diagnostic procedure given on page EC-506 of the factory service manual. All you should need is a basic multimeter and some time. Also, please tell us the manufacturing date of your Pathfinder so we can determine whether it's a 2001 or 2001.5 model year.

[440racer]

Manufacture date is 03/2000.

I'm dowloading manual right now. I REALLY appreciate you passing along this link to me.

Thanks,

Scott

[Towncivilian]

Okay, you have a 2001 model year Pathfinder, with the infamous coil issues unfortunately. I suggest downloading the entire FSM, as it's an excellent manual and reference and is invaluable.

Let us know if you're stuck at some step during the diagnostic and we'll be glad to help you out.

[440racer]

You're right about my predicimant and questioning of the practitioner is correct as well.

I took the truck to him because when the problem began, he said the problem could more than just the colis, that it could be in the harness, a contact point, other component, etc.

When I took it to Nissan, they just said "replace all the coils and see if that fixes it" without any further suggestions. Then I read that the coils can be checked since I had used aftermarket coils and the indie had offered to do more in-depth diagnostics so I felt comfortable with him. He has been very fair with the costs for diagnostics so far and seems confident in his approach and I feel fairly confortable with him and his approach.

As you said these problems can be very complex so I wanted to get some expert feedback and make doubly sure that the technician and I weren't throwing money away only to have the problem remain after replacing the ecu.

THanks again.

It's likely that a condenser can fail, but as Towncivilian has mentioned what condenser. The condenser for the A/C is a heat exchanger, where as the condenser used in conjunction with a relay is an electrical device that holds, squelches the DC current when a switch makes and usually breaks the circuit because DC does not want to break and stop flow.

The condenser for a relay in automotive would be at 12 V operation and the ECU is at 5 VDC. The ECU is robust on cars and trucks with failure to DC voltages by memory problems, breaking contacts that do not want to stop flow, by mishandling or ground problems. Of course there are more.

A relay may weld close and continue to conduct when the relay control has issued a stop condition or the relay is held open because the contact is broken, or the trigger mechanism has failed the relay and it is stuck open, closed or part way and depending on the problem any fusing may or may not come into play because of a no excessive loading but rather a conflict of what should be on or off at a certain time.

Getting into the head of a practitioner testing a circuit or a bunch of circuits as in a ECM is about impossible because of the lack of mind reading, but the logic can be examined and a possible yes or no or what?...Yes it is possible, but is it probable.?!.

You chose this person to deal with a particular problem and then you are curious about his answer, his expertise. This is usual from my experience based directly on the costs spent so far diagnosing the problem(s). Some things are not simple to fix because there is simply too much, too many thing that can go wrong and when that happens the fixer feels... replace. With my experiences many guy fix by replacing parts because they do not know how to troubleshoot. The world of fix is wrought with many of these types because the art of learning the correct way is too long, too expensive and in fact we are a throw away world.

I understand your predicament and wish you well.

[440racer]

Thanks Towncivilian. I just downlooaded the entire manual and previewed page 506. I will likely have questions. I do have e multimeter and will try the proceduews outlined.

I assume that my technician has the manual but if he does not would it be improper to provide hime with a copy and ask that he follow the procedures outlined if that's not what he's done/doing?

Thanks again.

Okay, you have a 2001 model year Pathfinder, with the infamous coil issues unfortunately. I suggest downloading the entire FSM, as it's an excellent manual and reference and is invaluable.

Let us know if you're stuck at some step during the diagnostic and we'll be glad to help you out.

[440racer]

Towncivilian,

I have not yet began the diagnostics outline below but I did try swapping relays and this is what happened:

I swapped the relays and the truck would still crank and run.

So, out of curiosity I pulled the elec. ignition fuse from the fuse block and it was good. Then after reinserting the fuse, the truck would crank but not start.

After panicking a little I put the old relay back where it was and the engine does run !?!

Any ideas?

Swap out the ignition relay with any known working blue relay (blower motor relay is right next to it, use that) and see if the engine runs. The relay is located behind the coin tray, it's the one on the far left. Or buy a new one if you want, or find one at a junkyard. I think your ECU is fine.

What "condenser" are you speaking of? I know of no such thing, other than the A/C condenser and its related components. Even a general search for "condenser" on Courtesy Parts yields only A/C parts. Maybe I'm having a brain fart here. Could you link to the thread you mention? Do you mean power transistor, possibly? EDIT: Looking at the FSM, there is indeed some "condenser" component. And the FSM says to check the ECM relay, not the "ignition" relay.

Unfortunately, 2001 model PFs commonly have issues with ignition coils. The 2001.5 revision have different coils as a result.