Question about 2002 Nissan Altima

1 Answer

P0420 and U1001

Getting U1001 and P0420 codes, car is also having electrical problems when turning on AC wipers stop working or intermittent and headlights go on and off really fast....relays clicking really fast as well... Any ideas....thanks a lot.

Posted by on


1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points


    An expert that got 5 achievements.


    A rookie expert who has answered 20 questions on their first day.


    An expert who has answered 20 questions.

  • Expert
  • 45 Answers

U1001 indicates that the ECM either isn't, or at some point in time wasn't, in communication with other controller modules on the car. From the sounds of it, I would suspect the BCM. Check the wiring harnesses at both of those places. If they are fine, you're probably going to have to replace the ECM, or spend some time looking for a short "somewhere" in the vehicle wiring, which can be a long and painful experience and would probably be wasted time in this case.

Posted on Jul 14, 2013


6 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.

Posted on Jan 02, 2017

  • 122 Answers

SOURCE: wipers dont work whe tha cars is starter but if we

check your wires for a brakein the signal wire

Posted on Jun 05, 2009

  • 5660 Answers

SOURCE: Intermittent electrical problem - 2004 Nissan Altima

You did say, "Any Input", right?

I had this problem with a 1992 Pontaic Bonneville.

Customer brought it in, and after days of diagnosing it drove me crazy. Turned out to be the wiring harness that goes from the camshaft sensor, and crankshaft sensor to the coil pack, had breaks in the wiring.

Everything checked out with a multimeter. All sensors, and related hardware checked out. Seems this wiring harness is doomed to fail after time goes by, because of the location. It's behind the water pump on this V6, 3.8 Liter transverse engine.

NO, I didn't replace it with a GM part! I made my own, and KNOW it will last now!

Such a JOY to get to! I put myself to sleep at night thinking about how much Fun(?) that was!

Posted on Jul 18, 2009

  • 8269 Answers

SOURCE: If my dash lights, running lights and tail lights

sounds like you have a short or perhaps a bad ground wire. Can you check the current at the relay socket? That would tell you if the short is after the relay or before it.

Posted on Sep 22, 2010

  • 528 Answers

SOURCE: Okay.. so i have a 1993 Nissan Quest that the high

You really need to verify a good clean ground for each headlight - it is possible you have corrosion either on the end connections or in the middle of the wire. It may be a good idea to just replace each ground wire for the respective light. Splice into the existing ground and run it to a new location, ensuring there is no paint or rust in your connection and putting dielectric greaseon the wire end,terminal, and underside of the head of your fastener. The cut the old wire so that fault cannot cause issues with your new ground. Don't wrap your new wire around a bolt - use the proper gauge eyelet terminal. If you use a pre - existing ground ( like on the alternator bracket ) wire brush the bolt head underside and mounting area clean along with whatever eyelet terminal there, grease all sides using fresh dielectric grease and tighten bolt securely.
This should cure your problem - if not, then test ( and replace if necessary ) whatever headlight relay (s ) you have - they may overheat and short out, causing a power surge that would blow the bulb.
Good luck!!

Posted on Nov 20, 2010

  • 6468 Answers

SOURCE: My 97 sentra intermittent wipers stop at weird places. What to fix?

inside the wiper motor there is a park switch and it might have failed

Posted on Jun 15, 2012

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Bucking rough idle and coding (P0463, P0550, p0037 & U1001)

With that combination of codes I would suggest checking the grounds to see if any have come loose. The first three codes are related to fuel level, power steering pressure, and possibly an oxygen sensor. The U1001 code means that there is a communication issue within the electrical system concerning sensors. When the sensors aren't working together correctly it can cause multiple problems including misfiring and rough idling. Check the grounds first, if they are fine then I would recommend taking it to someone who can check the rest of the electrical system.

Apr 23, 2014 | 2003 Nissan Sentra

1 Answer

Wipers not working

A little trick to try is untightening the mounting bolts of the wiper motor and then retightening. Sometimes its a matter of re-establishing a good ground.

The wiper parking problem is an internal wiper motor function. Some electric contacts are suppose to derail the motor and it is suppose to cycle into the locked position and turn off. Its last movements are automatic.

The intermittent part of the problem can be the contact switch on the turn stalk but there is a timer box on some models which the stalk switch controls. Some wiper motors have the timer box beneath a shield on the wiper motor. Those controls can be changed.

Mar 19, 2014 | Ford Fusion Cars & Trucks

1 Answer

U1001 code

Go to the Dealer they ll tell you Dont Do This By Yourself you will create more problems cause you not experienced in that field.

Jul 14, 2013 | Nissan Cars & Trucks

1 Answer

Wiper intermittent operation/automatic stowing does not work.

Hey Anon,
I just finished replacing the intermittent (wiper motor pulse board) control on my vehicle.. it was doing exactly as you describe.. it wasn't hard.. just time consuming..

Jun 16, 2017 | 1992 Dodge Stealth

1 Answer

Windshield wipers and Turn Signals Do Not Work Intermittently

It sounds like the multifunction switch has had it. It is not real expensive but there may be under lying electrical problems

Jul 28, 2009 | 1992 Chrysler Imperial

1 Answer

Wipers won't stop wiping.

Sounds like your intermittent wiper circuit is defective. Normally the intermittent feature is engaged by one of the functions on the multi-function switch (usually on the steering column). The circuit of the intermittent wiper periodically activates a relay that closes across the "Wiper On" switch. Your intermittent wiper circuit is likely defective and holding its relay closed (or the relay is stuck closed), thereby keeping the wipers on. Note: The wiper motor has an internal switch that opens when the wipers are in the park position and that is designerd to stop the wipers in the park position. When you turn on the wipers (or the intermittent relay is closed), the motor's internal switch is shunted such that the wiper does not stop at the park point of the cycle.

Apr 27, 2009 | Ford Explorer Cars & Trucks

2 Answers

Wipers do not work in intermittent position. They do work in low and high speeds but do not automatically return to the park position. They stop wherever you turn the switch off.

i belive that your wiper switch has gone out on the intermittent side. this is a very common problem.
I hope this helps you
Please leave rating

Apr 21, 2009 | 2000 Isuzu Amigo

1 Answer

Intermittanwipers t inop on renault cleo

try replacing the wiper relay

or could be a faulty wiper intermittent part of the switch

Apr 11, 2017 | 2003 Renault 181

4 Answers

Windshield Wiper Not Working Properly

Well sure enough all I had to do was replace the circuit board...wish I had done this a couple months was so easy to do and will now be much easier to drive with being able to see clearly again....

Dec 22, 2008 | 1999 Chevrolet Suburban

Not finding what you are looking for?
2002 Nissan Altima Logo

228 people viewed this question

Ask a Question

Usually answered in minutes!

Top Nissan Experts


Level 3 Expert

76070 Answers

Phil Lovisek
Phil Lovisek

Level 3 Expert

726 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22156 Answers

Are you a Nissan Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides