JimGrabs

Hello again! Today, I've got a few problems and trouble codes, not sure if any of them are linked or if I just have really bad luck. To start with the trouble codes, I've got:

• P1320
• P0755 (Will not shift into 3rd or 4th)
• P0720
• P0505 (Intermittently, after replacing IACV and ECU works well but idles a smidge high, ~800-900rpms in p/n, maybe needs relearn?)
• P0217 (Usually after driving a bit, maybe related to high idle? Just replaced one of the rad fans and topped off coolant)
• P0325, every now and then

Aside from the codes, I there's a few smaller problems, being:

• Slow/sluggish acceleration
• Horn won't stop blaring, have the relay pulled, test light shows grounded signal on horn relay

Any help is appreciated. I know it's a long list, and I feel like I just have really bad luck, but don't have enough knowledge to try and link everything together.

DennisMik

iTrader: (2)

P0325 - Knock sensor - the sensor is detecting that the engine is not running properly. You already know it. This is a reminder, not a problem. It will go away when the other problems are resolved.

P0217 - Malfunction is detected when engine coolant temperature is excessively high under normal engine speed. See page 313 -
http://boredmder.com/FSMs/Nissan/Maxima/2001/EC.pdf

P0505 - See page 429 -
http://boredmder.com/FSMs/Nissan/Maxima/2001/EC.pdf

P0720 - Malfunction is detected when TCM does not receive the proper voltage signal from the A/T revolution sensor. See page 114 -
http://boredmder.com/FSMs/Nissan/Maxima/2001/AT.pdf

P0755 - Malfunction is detected when TCM detects an improper voltage drop when it tries to operate shift solenoid valve B. See page 177 -
http://boredmder.com/FSMs/Nissan/Maxima/2001/AT.pdf

P1320 - Malfunction is detected when the ignition signal in the primary circuit is not sent to ECM during engine cranking or running. See page 506 -
http://boredmder.com/FSMs/Nissan/Maxima/2001/EC.pdf

High Idle Speed - If the target idle speed is out of the specified value, perform “Idle Air Volume Learning” before conducting P1320 diagnostics.
See page 67 for adjusting procedure, Page 643 for idle speed specifications.
http://boredmder.com/FSMs/Nissan/Maxima/2001/EC.pdf

- - - - - -

Reading the possible causes to all these problems, all indicate possible wire harness problems. And the wires for most of these problems seem to be in the same general vicinity, making me wonder if you hit somethin and damagad the wires. If you damaged the wires to the flywheel crank sensor, this could cause P1320. The sensor is used to control the spark timing. Improper timing (spark advanced too much) can cause overheating - P0217. What does your temperature guage show?

The P0505 is trickey. Engine coolant temperature plays a part, the crankshaft sensor plays a part, the air control valve on the power steering plays a part. Even the idle speed being off plays a part.

So get under the car and check the wires for damage in the driver front area, the crank sensor, the A/T park neutral switch, that area.

krismax

iTrader: (15)

If the p0505 goes off on a 00-01 most of the time IACV and ECU needs to be replaced at the SAME time. With OEM IACV and verified good ECU.

Nissan screwed people over with this. Should be a recall. I find many cars in junk yards from this. G20,pathfinders,maxima,I30,QX4. With the ECU's fried.

It throws other codes when the ECU is going bad. I just replaced two IACV and two ECU's on a i30,before i got the winning ticket.

Replace either or and there both a goner. Even turn the key forward and the engine not on, for a few minutes the ECU will fry the IACV. The ECU doesn't even show signs of being bad.Doesn't have burnt chips or it doesn't even have to smell. To still be bad.

This car has 74k miles on it. And the coolant can leak in the IACV even at 50k. And the motor mounts ,another disaster . Cut the plugs off them.

Do what dennis says,but i think you have multiple problems. Nissan failed with this engine management system.

JimGrabs

I've replaced both the IACV and ECU, unplugged the motor mounts and checked the new iacv for leaks right from the get go, and have a snap on scanner used to test and actuate the IACV, it's confirmed working, it's after driving for a bit that the IACV code throws, and it's usually after it starts running hot, and my guess as to why it runs hot it because the transmission won't shift into 3rd or 4th, and where I live in Texas most speed limits are 50-65, so motors under ~3500-4000 rpms of stress constant for a few minutes at a time. But as for what Dennis said, I'll be looking into the wiring for issues. You said that was the driver side in the front? I bought the car a few months back and it looked like it had been bumped around a little bit, so that's definately on the table. I did forget to mention in the OP, there was a code for a crank sensor once, but I haven't seen it since, so I'll probably be starting with the crank sensor and inspecting the wiring. Thanks for the input y'all, I really appreciate it, and I'll be updating as I replace things.