Problems with 01 Frontier CC....help!

Desmo · Mar 23rd, 2004, 03:12 PM

Hi all,

I have had my 01 Crew Cab since new and it has just over 100k miles. I was having some valve noise (it was very wierd sound under load) or atleast that is what I thought it was so I took it to the dealer. Just got the diag and they say that all it is is the exhaust manifold. They are asking $700 for parts and labor to replace the left side...OK. So can deal with that I guess. Cracked manifold???? whatever.

While it was there I told them that my AC was not functioning as of late (it has not been used for a few months) and to please look into that. Service guy calls me and says that they can not get a ground signal from the AC and that they need to replace the ECM unit to fix the AC....OK. I CAN NOT DEAL WITH THAT.

Does this sound normal to anyone?....I did a search but found nothing about ECM's being replaced to fix an AC problem. The dealer wants $800 bucks for the ECM.

Thanks

jadcock · Mar 23rd, 2004, 06:24 PM

Cracked exhaust manifolds and/or broken studs are very common on Nissan V-6 engines from this era. If this were a domestic brand, they'd call it faulty engineering and poor quality control. But it's Nissan, so it's "just one of those things."

I've never heard of the ECM going bad and causing the A/C not to work. I'd take it to a local garage you trust (if there's one near you) and have them check out the problem. You may also have them do the exhaust manifold replacement, likely for much less than the dealership will charge you. The A/C problem may simply be a bad ground, that can be fixed without replacing the ECM.

1997XETruck · Mar 23rd, 2004, 06:26 PM

Quote:

Originally Posted by Desmo

...AC and that they need to replace the ECM unit to fix the AC....OK. I CAN NOT DEAL WITH THAT. Does this sound normal to anyone?....I did a search but found nothing about ECM's being replaced to fix an AC problem. The dealer wants $800 bucks for the ECM.

Sounds fishy to me. The ECU controls the A/C with a ground signal, but you won't get a ground signal if the system pressure is too low (low on freon) or too high, the a/c evaporator sensor is showing that the evaporator is frozen, or the compressor protection sensor is showing that the compressor has overheated. Of course, all of this is based on my experience with the A/C on my truck and Q45s - not specifically on your model.

It is extremely rare for Nissans to have ECU problems unless they're damaged by an accident or water leaks.

If you're technically inclined, you can download your service manual and TSBs on at www.nissan-techinfo.com with the $20 one day viewing subscription and trace down exactly what's going on and how the system works.

I'd ask the dealership what the low and high side pressure readings are for your A/C system. That'll tell us a lot...

Heath

himilefrontier · Mar 24th, 2004, 01:16 AM

A common problem on Nissan Frontiers is the A/C cycling switch going bad either shutting off the A/C entirely, or failing to cycle the compressor clutch leading to it's eventual failure due to excessive system presure causing it to slip. I do not think it is the ECU causing the problem.If it is, try going to a late model salvage yard and buying a used one instead of the dealer's pricey new one. They should offer a warranty on it (30-90 days is typical and some offer a 12 month for a fee).If they do not, try another yard until you find one that does.