Question about 2004 Chevrolet TrailBlazer

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MAP sensor code shows fault , replaced sensor, code still goes on and off, book says to check all vacum lines for cracks or leaks. where are they all located any place to locate a diagram? Bill

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After you replaced the sensor, you will have to have a scanner connected to the computer again and have the trouble codes cleared. Otherwise the original code is still causing the light to come on.

Posted on Jan 06, 2011

  • Bill Noland Jan 21, 2011

    The code was cleared after the new one was replaces .
    How do u check to see if the fuel cap is defective?
    still looking for location of all the vacum lines

  • Jackie Miles
    Jackie Miles Jan 21, 2011

    A defective fuel cap would throw a code for an evap leak. There aren't that many vacuum lines on late model engines. All the lines would have to originate somewhere on the intake manifold or throttle body. You could have a vacuum leak at the intake manifold gasket. You can check for that leak by spraying starting fluid around the intake manifold gasket areas while the engine is running. If the starting fluid hits a leak, the engine will sppeed up momentarily. This would also work for other areas that might have a vacuum leak. Keep a fire extinguisher handy in case the starting fluid causes a fire. Do not use carb cleaner for this test. Too flammable.



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Why does the mass air flow code comes back after replacing the sensor?

Mass Air Flow sensor just measures incoming air flow at a predetermined rpm/load. The computer is saying the flow measurement is not correct. This can be caused by mechanical faults within the engine like a bad valve seat or timing chain but would generally be accompanied by backfires through the intake. Usually its caused by a vacume leak between the sensor and the intake valve,like the intake manifold,loose intake pipe clamps, broken vacume lines,a leaking vacume brake booster [it will hiss loud when you apply the brake],bad spark plugs/wires, a clogged catalytic converter, stuck open egr valve or pcv valve,bad oxygen sensor or even a very clogged air filter. I know there is a lot listed but the MAF or MAP sensors show general flow through the engine that can be affected by several things. A vacume tester from your local auto parts store is about 30bucks and usually has instructions how to test for vac. leaks within the engine also to determine a if thers is bad valve seat or clogged exhaust.

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I have a 2006 dodge Durango SLT 4.7 it is stalling sometimes when a take a corner and it jerks really hard just driving down the road. We had the code checked they cleaned my map sensor. This did not...

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Has codes 14 52 and 55 will not pass smog car runs fine the hc (ppm) are901 and the co is10.27

14 = MAP sensor voltage below .16V or over 4.96V
52 = Oxygen sensor stuck at rich position
55 = End of codes (not a fault code in itself)

Would appear that you have either a bad MAP sensor, or a leaking vacuum line somewhere.

The bad readings from the MAP sensor will cause the trouble code with the oxygen sensor (and the reason why you failed the test,) but this is not to say that the oxygen sensor can't be bad also.

Start with the cheapest thing, tracing vacuum hoses and lines for cracks and/or leaks. There should be a diagram somewhere under the hood that shows you the routing of the lines, attached to the underside of the hood or possibly on the front area near the radiator. With the age of the vehicle, I wouldn't doubt that this is the problem.

If everything checks fine with the lines, then try replacing the MAP sensor. These do have a tendency to fail.

Good luck, line tracing is bot a fun job, I've been there many times.

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03 neon sxt 2.0. Po440, 441

Those are indicators for a fault in your Emission Control System. There are a lot of things that can cause them to appear but the most common is actually a code you haven't mentioned. The O2 Sensor under the driver side of the vehicle. If your looking for a book on the vehicle Auto Zone sells a Haynes Manual for the vehicle. I recommend you use that book and have them look at the codes with a code reader. Also have the Gas cap checked for leaks. A vacum leak on the fuel system can cause this fault to appear. If the gas cap is good I would replace the O2 Downstream sensor, It is located just forward of the catalatyct converter on the driver side under the vehicle.

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Could be anything, its one of those thigns that are hard to figure out sometimes. Could be a EGR valve not working properly, could be MAF or MAP sensor, failing O2 sensor(s) as well. or simply a vacume leak around the throttle body or at a vacume line.

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What motor is in this s-10? 2.5 4 cyl? 2.8 V6?

im thinking if it was a fuel supply problem you would notice the issue at fast idle when cold as well.

also. how does it idle when it warms up?

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I have fault code 00575 intake manifold pressure on my audi a4 soft top were in engine is this component found

I assume it is a turbo diesel? Then:

Location of the sensor:
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- later models on the air intake duct, with wiring going to the ECU.

The fault may often be caused by:

- air leaks in MAP sensor line to the ECU (early ones only) or any of the vacuum control line hoses. This normally due to perished/loose flexi pipes, etc).
- leaks in the air hoses going between turbo/engine/intercooler. Can be spotted by slight oil contamination at the point of leak.

Or it's variable vaine sticking (even intermittently) in the turbo due to contamination, preventing the turbo from performing according to the ECU demand, and hence being 'shut-off' by th ECU

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