2000. What are the probable causes of DTCs P0412, P0443, and P0449?

I would try disconnecting battery again. Disconnect both cables and touch them together for a few seconds. This will reset all modules. Wierd that you had so many codes after just disconnecting battery. Sometimes very hard to tell if ecm is bad.

(which engine. ?????)_
as always check all fuses. and scan the ECU for DTCs. first.
there is no need to fix OBD2 cars like 1980 cars (hard rows to hoe)
it can be 2 problems this......
lets fix the easy one first. idle. (and hope for moving issues to fix for free) it idle car is parked, so is 100% safe tests. (not moving)

so it surges at idle.
questions.?
1: hot or cold or both.?
2: low extreme RPM and high at idle.
400 to 800 RPM? surge.
1000 to 2000. what? numbers tell the tale.

first off, idle is the last thing to work right on any engine.

there are many ways to find what is wrong.
fix idle surge way.
i make sure that the engine holds closed LOOP status.
hot idle, if not , i fix that first.
keep in mind if not in closes loop and lean
all lean engine surge and guess what the ISC will add to the surge
because idle is way too slow, so the ECU open the ISC wider
and wider and its still too slow, so the ECU resets the ISC
this cause a worst hunt (surge)
the ECU adjust spark time and the ISC to get 800 rpm. (spec. look up yours)
so say , i see closed loop failed, OBD2 scan page 1
i look at the O2 sensor an its stuck lean.
if stuck lean and it really is (o2 bad?) then its lean and it will surge
.
examples.
1: i find 02 sensor bad, (only effects idle and light steady cruise)
2: i find fuel pressure at 15PSI , hopeless low .
3: i find all injectors clogged. and lean.
4: with MAF EFI, ( i find maf reading too low, (dirty) causing lean.
5: if MAP car, i find the MAP stuck hard high vacuum causing lean.
not knowing what engine you have or the idle hot surge range,
i can not go farther.

the driving bog tells me,
1: scan the ecu ,get DTCs; do that first.
2: clean MAF if car has one, ask how..
3: check fuel pressure.


my guess is engine is lean. and starving for fuel all the time.
cept WOT.

MAF cars starve for fuel if there are any vacuum leaks.
MAP cars do opposite, they race fast with 100% full power.
MAF is air density EFI
MAP is speed density EFI.
apples and oranges diffr. so what engine.

Check for a vacuum leak. This can cause a higher than normal idle. It can also cause a surge since the idle air control tries to adjust the amount of air required to idle.

Hi Shelly,

The idle is controlled by the Powertrain Control Module via the throttle speed actuator. High idle can be caused by a malfunction in the idle speed system or it can be caused by a vacuum leak that is allowing the engine get air that it is not supposed to be getting.

The best way to diagnose this problem would be to FIRST scan your computer network in your vehicle and collect any Diagnostic Trouble Codes (DTCs) thay may be present. There is a good chance that there will be a DTC stored that will lead you directly to the source of your problem.

If there are no DTCs present, then some manual testing, using a scan tool to excercise the throttle actuator will be necessary to help determine the cause.

Hi Linda,

You will probably get many "guesses" about what is causing your problem. Here's the facts:

There is only ONE thing that will cause your engine to idle too high. It is getting too much air.

Now, the REASON it is getting too much air can vary greatly. There could be a vacuum leak caused by a cracked or split vacuum hose or an intake plenum or manifold gasket leak. It could be caused by a sticking or defective Idle Air Control (IAC) motor. It could be that the Powertrain Control Module (PCM) is COMMANDING the IAC to open due to faulty input from one of the sensors like a bad Throttle Position Sensor (TPS) or a defective Engine Coolant Temperature (ECT) sensor. Or it could even be a malfunctioning PCM.

If you cannot find anything obvious like a broken or leaking vacuum hose, then I highly recommend that you save time, effort and MONEY by having the computer system properly diagnosed using a scan tool that can read live engine data. This is the ONLY way you are going to find out for sure what is really going on. First, there may be Diagnostic Trouble Codes (DTCs) stored in your computer that may lead you directly to the cause. Then, DTCs or no DTCs, the live engine data will help eliminate some of the possibilities. For example, if the Long Term Fuel Trim data is displaying negative numbers, it is most definately being caused by a vacuum leak somewhere. If the Throttle Position Sensor closed-throttle voltage is reading 3 or 4 volts, then you would know that the PCM is commanding the idle to be high due to faulty data from the TPS.

- OR you could just keep on guessing and replacing parts....

replace the egr positioning sensor.

P0449 - Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction

P0455 - Evaporative Emission Control System Leak Detected (no purge flow or large leak)

Both are refer at EVAP system; other EVAP DTCs: P0440 - P0441 - P0442 - P0443 - P0446 - P0453 - P0455 - P0456

This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. It means a large leak has been detected. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

Symptoms: You likely won't notice any drivability problems.
Causes: most likely means one or more of the following has happened:
A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
Other leak or damaged piece in EVAP system

Possible Solutions: the most common repair is to:
Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
Otherwise, replace the gas cap, and/or
Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary


Hope helps.

high idle concern is probably caused by either a sticking throttle plate, defective IAC or the computer is commanding the high idle for another reason.

the blower motor is found behind the glove box in the HVAC case

this is normal, if the idle wasn't high (about 2,500 RPM) the engine wopuld stall out until it warms up to normal temperature. If it is above 3000 RPM for more than a few seconds you have a problem.

what is thye correct idle rpm in park 1999 amigo