Error codes P0101 and P0121

Hi. So I finished replacing my LIM gaskets and took my 2002 grand prix gtp for a test drive on the freeway. After 13 miles my engine splutter and the RPM dropped way down and I could no longer accelerate. The engine was dying. I let it sit for a couple of minutes and the engine came back on normally.

I retrieved the error codes of P0101 and P0121. My research indicates that does deals with the MAF sensor and TPS sensor. I will test those out. However, my question is if I am having problems with those sensors will the supercharger not also work?? While on the freeway I was trying to engage the supercharger, but I did not hear it come on nor did the boost gauge bar on the car computer screen show any bar indications. Your information would be much appreciated.

While doing the LIM gaskets I also changed the PCV, EGR gasket, Throttle Bottle Gasket, and Valve Cover gasket. Could I have contributed the error codes by doing any of those things? Also, I've had error code P0401 for like 5 years now. Apparently, I think I have finally discovered the culprit after all these years of trying to solve the issue. The MAP sensor vacuum hose to the manifold had a crack that was just so big the two ends of the hose were barely holding onto each other. From the wear of the crack it must have happened a long time ago. For some reason I never checked the vacuum hose. This is dumb, but after having that problem for so long and fixing it that wouldn't contribute to error code P0101 and P0121 could it? It's just weird that after all the maintenance that I just did I suddenly have these issues. Rather I would imagine that performance should improve.

Thanks

those two codes are related....... you do not have something hooked up right. check all connections make sure the vent tube is installed all the way in the snorkel. make sure the maf is not in backwards. there is an arrow for flow direction. unplug and replug all of the connections... here is a diagnostic flow chart from all data.


CIRCUIT DESCRIPTION
The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits:


An ignition 1 voltage circuit
A ground circuit
A signal circuit
The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. The PCM uses the following sensor inputs in order to calculate a predicted MAF value:


The barometric pressure (BARO) at key ON
The manifold absolute pressure (MAP)
The intake air temperature (IAT) The engine coolant temperature (ECT)
The throttle position (TP)
The engine speed (RPM)
The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. DTC P0101 sets if the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value.

CONDITIONS FOR RUNNING THE DTC


DTCs P0102, P0103, P0107, P0108, P0121, P0122, P0123, P0401, P0403, P0404, P0405, P0440, P0442, P0443, P0446, P0449, P1106, P1107, P1121, P1122, P1404, and P1441 are not set.
The engine is running.
The ignition 1 signal is between 9-18 volts .
The MAP sensor is less than 80 kPa .
The change in the MAP sensor is less than 5 kPa .
The TP sensor angle is less than 15 percent for the VIN K engine, or less than 30 percent for the VIN 1 engine.
The change in the TP sensor angle is less than 5 percent .
The traction control is inactive, if equipped.
The above conditions are met for more than 2 seconds .
CONDITIONS FOR SETTING THE DTC
The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 40 seconds .

ACTION TAKEN WHEN THE DTC SETS


The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC


The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
Inspect for the following conditions:


An incorrectly routed harness - Inspect the harness of the MAF sensor in order to verify that the harness is not routed too close to the following components:
The secondary ignition wires or coils
Any solenoids
Any relays
Any motors
A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leak downstream of the MAF sensor.
A skewed or stuck TP sensor
A wide open throttle (WOT) acceleration from a stop should cause the MAF sensor g/s display on the scan tool to increase rapidly. This increase should be from 4-7 g/s at idle to 150 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
The barometric pressure (BARO) pressure that is used in order to calculate the predicted MAF value is initially based on the MAP sensor at key ON. When the engine is running the MAP sensor value is continually updated near wide open throttle (WOT). A skewed MAP sensor will cause the calculated MAF value to be inaccurate. The value shown for the MAP sensor display varies with the altitude. With the ignition ON and the engine OFF, 103 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
High resistance on the ground circuit of the MAP sensor can cause this DTC to set.
Any loss of vacuum to the MAP sensor can cause this DTC to set.
If you suspect the condition may be related to aftermarket accessories, refer to Checking Aftermarket Accessories in Diagnostic Aids.

If the condition is intermittent, refer to Intermittent Conditions. See: Initial Inspection and Diagnostic Overview\Diagnostic Strategies

TEST DESCRIPTION

Steps 1-5





Steps 6-11





The numbers below refer to the step numbers on the diagnostic table.


This step determines if the MAP sensor voltage is within the proper range at idle.
This step determines if the MAP sensor responds properly to the change in manifold pressure.
This step determines if the TP sensor is operating properly.
This step determines if any mechanical faults have caused this DTC to set.

ohh and the supercharger runs all the time. boost depends on acceleration and with you not having the correct air flow readings from the maf it will be hard to accelerate. make sure the maf is not dirty.

Thanks guys. Those advice sounds great. I will give it a shot. I forgot to mention that I neither took the MAF nor the TPS off. I, however, idiotically did take off the Idle Air Control (IAC) Valve but in the process broke one of the screws and had to drill it out. Now theres just a tiny nut and bolt holding one side. It aint in there very tightly. I labeled all my connections when I took them apart so I doubt that will be the case, but I will double check. Tomorrow I will use a little gasket sealant to better seal of the IAC and try to tighten it up. If my IAC is not in tightly, can they affect the TPS and MAF sensors? The car died out on me six times tonight only when I decelerate.

Thanks

the IAC passage is behind the MAF sensor, so you will be sucking in air behind the MAF throwing the readings off. The TPS reading may also be affected, because the signal from the MAF and MAP sensors do not correlate with the computer's programming for the given TPS reading due to the vacuum leak at the IAC housing.

I think I'm starting to get somewhere. I will give it one more try and if I can't figure out by this weekend I think I'll just take it to a car shop. Some quick questions.

My MAP pressure according to my scanner is at a constant 29.025 Hg no matter what my RPM is. Could this be indicative of a leak, especially from the intake manifold? When I was screwing the intake manifold bolts back on I did not use thread lock as the instructions that I used from www.alldatadiy.com did not state so although it says to brush off the old thread lock. Can I get a vacuum leak from not using thread lock on the intake manifold bolts? What about where we put a dab of black rtv at the plastic end seals when replacing the gaskets. If not done properly, can a vacuum leak form from there?

Also, no matter what my rpm is the scanner indicates that my TPS position angle is at 0%. Averages for Long Term Fuel Trim=36.71875 % and Short Term Fuel Trim= 25%. I've checked the wirings and I do get a voltage of 5 with my multimeter for both the wires to the TPS and the MAF sensors. I haven't been able to get the proper resistant torx tools to take these two off, but I will be able to get the tools today. I will test them.

Any thoughts would be helpful. Thanks.

It looks like you either have a wiring problem with the TPS or the sensor is bad, since you say you didn't remove it I would suspect the wiring might have been pinched somewhere during the process.

The LTFT readings are too high. The ideal is to have those as close as possible to 0 I would say you have a vacuum leak (a positive value means the PCM tries to compensate a lean condition).

Threadlocker helps to keep the bolts front loosening with vibrations. And the RTV sealant only helps to keep the gaskets in place, the sealing action is done by the gasket itself.

Were the bolts properly torqued and the tightening sequence was followed?

Oscar.

it's a matter of tracing your steps very carefully and finding your mistake. If it wasn't doing this before then something is wrong with what was done. like oscar said maybe a pinched wire. unfortunately I would tell you to start from the top and trace all of your steps. a shop is going to charge you hours of labor to find a mistake and then want to re-do your intake. maybe take some pictures and post them????? maybe one of us will see something wrong.

Thanks guys,

I am in better spirits today so tomorrow I am going to retrace all of my steps. I did check the wirings to the tps and maf and I do get a constant 5 with my multimeter. I took out the tps and watched the resistance increased uniformly on my multimeter as I turn the metal hinge on the inside.

If the following reasoning is correct, then I may have solved all of my errors . The intake manifold vacuum line....after the connection under the supercharger snout it goes to the MAP sensor for a 2002 grand prix gtp right? Then that would imply that the middle vacumm connector (circle in red) in the picture below should be not connected to anything?? if yes, is it supposed to be closed off or left open? If what I've said is correct, then I have not been connecting the vacuum line to the MAP sensor and have been connecting to the point circled in red. If what I have said is correct, besides moving the vacuum line to the MAP sensor, what do I need to correct for my error?

Since I've never done a LIM before, I've got a dumb question. The gasket set by Felpro that I purchased contained two sets of plastic end seals (one orange and one blue). If you click on the following link it will take you to autozone with pictures of the set that I bought.


http://www.autozone.com/autozone/parts/Felpro-Intake-Manifold-Gasket/2002-Pontiac-Grand-Prix/_/N-jhr73Z93xym?counter=1&filterByKeyWord=intake+gaskets&fromString=search&itemIdentifier=217566_259711_5297_

My dumb question is, I don't have to use both the blue and orange end seals do I? From the video with "DuBob" it seems that I only need to use one of the two set. I choose the orange set because I have holes to match the orange set. Am I correct for those that are familiar with this?

I'm going to just take everything apart tomorrow and see what happens. Last time I waited for 24hours after I installed the lower intakes before I started my engine. What is the minimum amount of time that I should wait before trying to start my car?

Thanks.

You're welcome!

I'm not sure about the blue/orange pieces AFAIK these might correspond to the first and second design of the gaskets set. Using the orange ones with the holding pins was the best choice.

Before you take everything apart, did you disconnect the battery cable to reset the PCM? If the computer learned the old readings from the MAP (with the cracked hose), replacing the hose has changed the entire values and since the TPS and MAF readings no longer correspond to the learned MAP values that might be causing your problems.

Just like Rick said, taking it to a shop will only cost money for something you can definitely do ;).

On the awaiting time I don't know, honestly never heard of it but I'm not an expert. I just did intake gaskets on my town car and I fired it up as soon as I had everything back together (about 1.5 hours) with no problems.

I ask the same question again, did you use a torque wrench and followed the proper sequence while tightening the bolts?.

Oscar.

Dear olopezm,

Yes, I did use a torque wrench and torque it to 11 ft/lb (I actually set it to 11.5 on my wrench) and I did do it in the sequence that was on alldata.com, basically starting in the middle and moving outward from opposite side to the other.

when you say to disconnect the battery cable, do you mean both the negative and positive terminal or just the negative?

Sorry, here is the picture for post #9.

That's good I just wanted to make sure you did ;).

Disconnecting the negative cable should be enough but you can disconnect both and touch them against each other (the cables only NOT the battery posts) for 30 seconds to drain the capacitors in the PCM and reset the data.

If the following reasoning is correct, then I may have solved all of my errors . The intake manifold vacuum line....after the connection under the supercharger snout it goes to the MAP sensor for a 2002 grand prix gtp right? Then that would imply that the middle vacumm connector (circle in red) in the picture below should be not connected to anything?? if yes, is it supposed to be closed off or left open? If what I've said is correct, then I have not been connecting the vacuum line to the MAP sensor and have been connecting to the point circled in red. If what I have said is correct, besides moving the vacuum line to the MAP sensor, what do I need to correct for my error?


Sorry I didn't see that text before.

The vacuum diagram I have doesn't shows where that port should be connected to but it definitelly HAS to have a hose running to it, if not that will result in a vacuum leak and a lean condition (which you have) causing your LTFT values to go up.

The following link shows a 1/4 (I think) hose connected to it running to the back of the engine; I'm thinking that might be the accesory hose, since that one and the brake booster are the only ones missing in the diagram, which should run to the passenger side fender and towards the interior of the car controlling your A/C system. Is the air coming out from the front vents or only from the rear (defroster) ones.

Click here (http://www.paulstravelpictures.com/GM-3800-II-PCV-Valve-Replacement-Guide/Pontiac-Grand-Prix-PCV-Valve-Replacement-003.html)

Oscar.

Oscar and RickisRad,

Thanks for your helpful advice. I have solved my problem. It has nothing to do with neither my TPS nor my MAF sensors. I made a very dumb rookie mistake.

Thanks to Oscar I traced my accessory hose and realized that it was connected to nothing. Somehow the accessory hose end that is supposed to be connected to my intake manifold got placed inside one of my wiring harness and so I did not see any loose (unconnected) hose. Because of this error I never connected my vacuum hose to my MAP sensor at all!!!Rather the hose end that was supposed to go to my MAP sensor, I had it routed to where the accessory hose should be on the manifold. I was driving on the freeway for like 15 minutes like this before my engine started to stall. Was I driving dangerously?

Thanks all again.