Question about 2004 Lincoln Aviator

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Lincoln2004 aviator check engine light is on code read 420 what does that mean

Engine light came on code read 420 what does it mean

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If it's a p0420 then it's a catalytic converter code.

Posted on Feb 19, 2015


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I couldn't find engine code for 420 but may be body code take to AutoZone for free test and code meaning

Posted on Oct 13, 2014


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Posted on Jan 02, 2017

michigan man

edgar walker

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SOURCE: Engine check light on, temp high, leaking a fluid

if the fluid pouring out of the bottom of the truck is anti- freeze you may need intake gaskets i just put some on a 2000 expedition that was doing the same thing please do not keep driving the truck dis way cause in a while it will cause more damage to the engine

Posted on Feb 11, 2009


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SOURCE: Don't know what dashboard diagnostic light means (03 Lincoln Avi)

there is a small button on the side by the shifter,with the engine running press that again and that light shoul disappear.

Posted on Mar 29, 2009


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SOURCE: my check engine light come on my lincoln aviator.

you will need to have a diagnostics check done they will tell you whats wrong with it

Posted on Oct 11, 2009

toney clark

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SOURCE: my check engine light come on my lincoln aviator.

take it and have computer scanned

Posted on Oct 12, 2009


SOURCE: what does it mean when

You have a System Malfunction,most likely a
Wheel Speed Sensor. (ABS System)

Check for codes and diagnose from there

Local shop is fine,better and cheaper than a dealer

Posted on Dec 18, 2010

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Related Questions:

1 Answer

What does bank 1 below threshold mean?

420 code is usually a worn out converter.

Dec 20, 2015 | 2004 Audi A4

1 Answer

Engine light code po420?

Code 420 refers to the catalytic converter in the exhaust pipe.
The code means the engine computer things the cat is not working correctly based on the data coming from the O2 sensors.
The sensors and the cat would need to be inspected.

Nov 17, 2015 | Chrysler Pacifica Cars & Trucks

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Why is my engine light flashing 8 times on my 09 rancher 420 efi?

get it checked by code reader when they flash shouldnt drive it may cause more damage

Feb 02, 2015 | Cars & Trucks

1 Answer

I have a 2003 saturn ion 4 door, it has a ton of miles 194k. Last week the alternator went out do I replaced it without a problem, then the day after the check engine light came on I hook up the diagnostic...


no FSM> and not looking up P0420?
no engine stated, so ill get it wrong too..?????????????
420 is cat monitor failure. "efficiency"
the most hard of all.

ill make a list from hard and expensive .
1: bad sensor 2 rear. you failed to do both, that was WRONG.
2: bad cat. (i can weld on any cat for $99 bucks.) i do it last.. dead last.
3: engine running real bad. BUY a scan tool, now.

so the o2 is new that leaves #2 or #3.
i never shot gun cats. but shops do, its not their cash, huh?

i connect a real scan tool (not one that misses factory DTC codes)
then look at pendings for P042o , see funny sensor readings there, bingo.
i check every PID. for all sensors to be sure they READ right.
is the engine holding closed loop status at idle, no fix that NOW.
is LTFT (long term fuel trim ) near 0 or at - 40 or + 40% (fix that next)
if trim is good, the engine.
If the front 02 is new, the AFR will be correct and the the front 02 will swing fast and the trim will be near 0 , -4 is near best.
tad rich , natural.
once the engine is running Stoich at light flat cruise. (close loop) the
cat will heal its self (bake dry) and stop throwing 420. ( a hope deal)
if not the cat is bad.

ive cured some of the most hard 420s,.

on some ratty engines, a new cat can in fact hide it , until it cooks to death and next year 420 are back.
id never do that because gas is expensive. fix engine first.

Jun 24, 2014 | Cars & Trucks

1 Answer

420 code with a check engine light

Code 420 means the O2 sensors are telling the computer the catalytic converter on bank one is not working correctly. Bank one is on the side with cylinder one.
The problem could be the cat, or one of the sensors, or a fuel mixture problem such as a vac leak in the engine or injector problem.
The sensors would need to be tested.

Jan 21, 2013 | 2005 Buick LaCrosse

1 Answer

On my 2002 yukon 1500 I have trouble codes of 171,174, 420 what is my problem

Basically this means that an oxygen sensor in bank 2 detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is generally the side of the engine that doesn't have cylinder #1.
Note: This DTC is very similar to P0171, and in fact your vehicle may show both codes at the same time.
You will more than likely not notice any drivability problems, although there may be symptoms such as a lack of power, detonation (spark knock), and/or a hesitation/surge on acceleration.
The catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream O2 sensor reading should be fairly steady. Typically the P0420 code triggers the Check Engine Light if the readings of the two sensors are similar. This is indicative of (among other things) a converter that is not working as efficiently as it should be (according to specs). It is part of the vehicle emissions system.
I hope this helps.

Mar 31, 2012 | GMC Yukon XL Cars & Trucks

1 Answer


The 420 code means you need the catalytic converter replaced. The TCS means Traction Control System. The green key is the theft system. Both lights MAY have nothing to do with the car shutting off Sometimes those lights will display when something elese makes the car stall. Perhaps a faulty crank sensor or the cat is so clogged its stalling out the car.

Mar 08, 2010 | 1999 Acura TL

2 Answers

Jeep cherokee check engine light is on

P0420 Catalyst System Efficiency Below Threshold (Bank 1)
do u have a catalytic converter, did u leave the sensor disconnected just to the rear of the catalyst?

May 27, 2009 | 1996 Jeep Cherokee Sport

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