# Check Engline Light after Replacing Fuel Injectors!!



## memarciniak (Jun 29, 2018)

Did the mass air flow send a code?
Also, go back to Autozone, and ask them to CLEAR your check engine light. If the check engine does not come back on then you're good. If the light does come back on, then post the code here, and someone will assist. 

Also, you can take the battery cable off for 15 minutes, and place your foot on the brake for 2 of the 15 minutes to ensure the power is drained while cable is off, then put the cable back on, and that CLEAR the check engine light too. If it comes back on, have auto zone read the code, and post the code here. They give you a print out, so post a pic of the print out too. Thanks.


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## rubensanchez07 (Jun 30, 2018)

Thanks, attached is the codes I got from Autozone. The DID clear it. But the light came back on. Same as before the car is shaking/trembling when idle. That's my concern. It shouldn't be doing that. It was doing so from the beginning, before i changed out the fuel injectors.




memarciniak said:


> Did the mass air flow send a code?
> Also, go back to Autozone, and ask them to CLEAR your check engine light. If the check engine does not come back on then you're good. If the light does come back on, then post the code here, and someone will assist.
> 
> Also, you can take the battery cable off for 15 minutes, and place your foot on the brake for 2 of the 15 minutes to ensure the power is drained while cable is off, then put the cable back on, and that CLEAR the check engine light too. If it comes back on, have auto zone read the code, and post the code here. They give you a print out, so post a pic of the print out too. Thanks.


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## memarciniak (Jun 29, 2018)

*Okay, but it looks electrical to me. You may have some wiring hooked up incorrectly. You're just going to have to track it down, and check it all out. *

*P1101 OBD-II Trouble Code: Mass Airflow Sensor Out of Self Test Range*

 P1101 means there is an issue with the mass airflow sensor system. It is likely due to a faulty sensor, bad connectors, or an air leak.
_P1101 code definition_
_The storage of a P1101 trouble code happens when the Powertrain Control Module (PCM) detects a fault within the Mass Air Flow (MAF) sensor system. Related codes that the PCM might store along with a P1101 trouble code includes a P1001, P1100, P1102, P1103, P1104, and P1105 code.What the P1101 code meansWhen a P1101 trouble code is stored, it means that the PCM detected a discrepancy with the voltage from the MAF sensor. This problem can be detected while the PCM is running a self diagnostic called a Key On Engine Running (KOER) test. When the voltage from the MAF sensor is greater or lesser than the voltage allowed by the manufacturer, the test fails._
*What causes the P1101 code?*

_Some of the possible causes of a P1101 trouble code include a faulty MAF sensor, faulty connectors or wiring within the MAF sensor harness, and an air leak either before or after the MAF sensor. A poor electrical connection within the MAF sensor circuit can also cause the storage of this code._
*What are the symptoms of the P1101 code?*

_In addition to the code storage and the subsequent illumination of the check engine light, symptoms of a P1101 trouble code include poor engine performance exhibited in erratic performance upon startup, rough idling, and reduced vehicle power while in operation. In addition, a vehicle with a stored P1101 trouble code can also experience a reduction in fuel economy._
*How does a mechanic diagnose the P1101 code?*

_To diagnose a P1101 trouble code, a mechanic needs to use an OBD-II scanner and a digital volt/ohm meter. In addition, the mechanic should perform the following steps:_


_Visually inspect the wiring of the MAF sensor harness. The mechanic should likewise check out the wiring, connectors, and components associated with the MAF system._
_Check the air filter for debris to make sure the flow of air is not obstructed._
_After making any necessary replacements or repairs, clear the trouble code, and test the system to see if the code returns._
_If the code returns, the mechanic should download any freeze frame data on the PCM in addition to all stored trouble codes._
_The mechanic should carefully remove the MAF sensor to see if it is dirty._
_Next, the mechanic should perform a smoke test to check for any leaks before or after the MAF sensor within the vacuum system._
_If no leaks are detected or the code returns after fixing any leaks and clearing the code, test the MAF sensor for reference voltage and ground signal using the digital volt/ohm meter._
_If no voltage or ground signal are detected, first disconnect the PCM and all related control modules, and then check the continuity of the MAF sensor and all related circuits for continuity with the battery ground._
_The mechanic can also check the continuity between the MAF sensor and the PCM, as well as continuity between the various control modules and the PCM._
_As a final step, clear the P1101 trouble code and retest the system to see if the code returns._
*Common mistakes when diagnosing the P1101 code*

_Mechanics often make the mistake of replacing the MAF sensor when simply cleaning it would have corrected the problem and cleared the P1101 trouble code. Another common mistake is to not check for vacuum leaks, which leads to the persistence of the code._
*How serious is the P1101 code?*

_While a P1101 trouble code usually does not prevent the operation of a vehicle, it can cause the engine to run roughly, lose power, and even consume more fuel. This code should be repaired as soon as possible, because prolonged driving with this code stored can lead to internal engine problems._
*What repairs can fix the P1101 code?*

_To repair and successfully clear a P1101 trouble code, a mechanic must complete the following steps:_


_Replace or repair any faulty, damaged, or loose wiring, connectors, or components within the MAF sensor harness._
_Clean or replace the air filter if it is dirty._
_Clean the MAF sensor with specialized cleaner. Allow the sensor to completely dry before replacing it._
_Repair any leaks within the vacuum system._
_Replace the MAF sensor if after cleaning the part it still does not work properly._
_Replace any faulty control modules, including the PCM, if they test as "bad." Replacing the PCM requires reprogramming on the part of the mechanic._
*Additional comments for consideration regarding the P1101 code*

When removing the MAF sensor for cleaning, the mechanic should take care to not damage the wiring. 

The wiring that connects to the MAF sensor is very delicate and easily damaged.


*P0171 System Too Lean Bank 1 Technical Description System Too Lean (Bank 1) *

What does that mean? 

This diagnostic trouble code (DTC) is a generic powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may be slightly different depending on the model. So this engine code article applies to Toyota, Chevrolet, Ford, Nissan, Honda, GMC, Dodge, etc. Basically this means that an oxygen sensor in bank 1 has detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1. The P0171 is one of the more common trouble codes. This code is triggered by the first downstream (front) O2 sensor. The sensor provides a reading of the air:fuel ratio leaving the engine's cylinders, and the vehicles powertrain/engine control module (PCM/ECM) uses that reading and adjusts to keep the engine running at that optimum ratio of 14.7:1. If something is not right and the PCM cannot maintain the 14.7:1 ratio, but rather there is too much air, it triggers this code. You'll want to also read our article on short and long term fuel trims to help understand the operation of the engine. Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time. 

Symptoms You will more than likely not notice any drivability problems, although there may be symptoms such as: a lack of power detonation (spark knock) rough idle hesitation/surge on acceleration. 

Causes A code P0171 may mean that one or more of the following has happened:


 The MAF (Mass Air Flow) Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. There could be a vacuum leak downstream of the MAF sensor Possible cracked vacuum or PCV line/connection Faulty or stuck open PCV valve Failed or faulty oxygen sensor (bank 1, sensor 1) Sticking/plugged or failed fuel injector Low fuel pressure (possible plugged/dirty fuel filter!) Exhaust leak between engine and first oxygen sensor Possible Solutions A lot of times, cleaning the MAF sensor and finding/fixing vacuum leaks fix the problem. If you're on a tight budget, start there, but that may not be the fix for certain. So, possible solutions include: Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling Inspect all vacuum and PCV hoses, replace/repair as required Inspect all hoses and connections in the air intake system Inspect and/or test the intake manifold gaskets for leakage Check for a dirty fuel filter and proper fuel pressure Ideally you'll want to monitor short and long term fuel trims using an advanced scan tool If you have access, you may want to run a smoke test
*
**P0171 System Too Lean Bank 1 Technical Description System Too Lean (Bank 1) What does that mean? *

This diagnostic trouble code (DTC) is a generic powertrain code. It is considered generic because it applies to all makes and models of vehicles (1996-newer), although specific repair steps may be slightly different depending on the model. So this engine code article applies to Toyota, Chevrolet, Ford, Nissan, Honda, GMC, Dodge, etc. Basically this means that an oxygen sensor in bank 1 has detected a lean condition (too much oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1. The P0171 is one of the more common trouble codes. This code is triggered by the first downstream (front) O2 sensor. The sensor provides a reading of the air:fuel ratio leaving the engine's cylinders, and the vehicles powertrain/engine control module (PCM/ECM) uses that reading and adjusts to keep the engine running at that optimum ratio of 14.7:1. If something is not right and the PCM cannot maintain the 14.7:1 ratio, but rather there is too much air, it triggers this code. You'll want to also read our article on short and long term fuel trims to help understand the operation of the engine. Note: This DTC is very similar to P0174, and in fact your vehicle may show both codes at the same time. Symptoms You will more than likely not notice any drivability problems, although there may be symptoms such as: a lack of power detonation (spark knock) rough idle hesitation/surge on acceleration. Causes A code P0171 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. There could be a vacuum leak downstream of the MAF sensor Possible cracked vacuum or PCV line/connection Faulty or stuck open PCV valve Failed or faulty oxygen sensor (bank 1, sensor 1) Sticking/plugged or failed fuel injector Low fuel pressure (possible plugged/dirty fuel filter!) Exhaust leak between engine and first oxygen sensor Possible Solutions A lot of times, cleaning the MAF sensor and finding/fixing vacuum leaks fix the problem. If you're on a tight budget, start there, but that may not be the fix for certain. So, possible solutions include: Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling Inspect all vacuum and PCV hoses, replace/repair as required Inspect all hoses and connections in the air intake system Inspect and/or test the intake manifold gaskets for leakage Check for a dirty fuel filter and proper fuel pressure Ideally you'll want to monitor short and long term fuel trims using an advanced scan tool If you have access, you may want to run a smoke test


*P0106 - MAP/Barometric Pressure Circuit Range/Performance Problem*

OBD-II Trouble Code Technical Description Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem What does that mean? This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles. Although generic, the specific repair steps may vary depending on make/model. The Powertrain Control Module (PCM) uses the Manifold Absolute Pressure Sensor (MAP) to monitor engine load. (NOTE: Some vehicles have a Barometric Pressure (BARO) sensor that is integral to the Mass Air Flow (MAF) sensor and do not have a MAP sensor. Other vehicles have a MAF/BARO and a redundant MAP sensor where the MAP sensor functions as a backup input in case of MAF failure. The PCM supplies a 5 Volt reference signal to the MAP sensor. Usually the PCM also supplies a ground circuit to the MAP sensor as well. As the manifold pressure changes with load, the MAP sensor input informs the PCM. At idle the voltage should be 1 to 1.5 Volts and approximately 4.5 Volts at Wide Open Throttle (WOT). The PCM looks for any change in manifold pressure to be preceded by a change in engine load in the form of changes in throttle angle, engine speed, or Exhaust Gas Recirculation (EGR) flow. If the PCM doesn't see any of these factors change while detecting a rapid change in MAP value, it will set a P0106. A typical MAP sensor Potential Symptoms 

The following could be symptomatic of a *P0106:* 
Engine runs rough Black smoke at tailpipe 
Engine will not idle Poor fuel economy 
Engine misses at speed Causes 

A P0106 could be caused by: 

Bad MAP sensor, 
Water/dirt intrusion affecting MAP sensor connector, 
Intermittent open in the reference, ground, or signal wire for the MAP sensor 
Intermittent short in the reference, ground, or signal wire for the MAP sensor 
Ground problem due to corrosion causing intermittent signal problem 
A break in the flexible air intake duct between the MAF and the intake manifold 
Bad PCM (do not assume the PCM is bad until you've exhausted all other possibilities) 

Possible Solutions Using a scan tool, watch the MAP sensor value with the key on, engine off. 

Compare the BARO reading with the MAP reading. They should be roughly equal. The voltage for the MAP sensor should read approx. 4.5 volts. Now start the engine and look for a significant drop in the MAP sensor voltage indicating the MAP sensor is working. If the MAP reading doesn't change perform the following: With the Key on, engine off, disconnect the vacuum hose from the MAP sensor. Using a vacuum pump, pull 20 in. of vacuum on the MAP sensor. Does the voltage drop? It should. If it doesn't inspect the MAP sensor vacuum port and vacuum hose to manifold for a restriction of some kind. Repair or replace as necessary. If there are no restrictions, and the value doesn't change with vacuum, then perform the following: with the Key on and engine off and the MAP sensor unplugged, check for 5 Volts at the reference wire to the MAP sensor connector with a Digital Voltmeter. If there is none, check for reference voltage at the PCM connector. If the reference voltage is present at the PCM connector but not the MAP connector, check for open or short in the reference wire between MAP and PCM and retest. If reference voltage is present, then check for existing ground at the MAP sensor connector. If it isn't present then repair open/short in the ground circuit. If ground is present, then replace MAP sensor. Other MAP sensor trouble codes include P0105, P0107, P0108 and P0109.

*P015B* O2 Sensor Delayed Response - 
Lean to Rich (Bank 1 Sensor 1) Lean to Rich (Bank 1 Sensor 1) What does that mean?

This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles (GMC, Chevrolet, Ford, Dodge, Chrysler, VW, Toyota, Honda, etc.). Although generic, the specific repair steps may vary depending on make/model. When an OBD-II equipped vehicle has a stored P015B code, it means that the powertrain control module (PCM) has detected a delayed response time from the upstream (first one after the exhaust leaves the engine, in front of catalytic converter) oxygen (O2) sensor or circuit for engine bank one. Bank 1 specifies the bank of the engine which contains the number one cylinder. Automotive O2 / oxygen sensors are constructed using a zirconium dioxide sensing element which is protected by a specially designed, vented, steel housing. Platinum electrodes are used to attach the sensing element to wire leads in the O2 sensor wiring harness which is connected to the PCM through the controller area network (CAN). The PCM is supplied with an electrical signal according to the percentage of oxygen particles in the engine exhaust compared to the oxygen content of ambient air. Exhaust gases are pushed into the exhaust manifold(s) and down pipe(s) where they flow over/through the upstream O2 sensor. Exhaust flows through the O2 sensor vent holes (in the steel housing) and across the sensing element and ambient air is drawn through the wire lead cavities where it is trapped in a small chamber in the center of the sensor. The trapped ambient air (in the chamber) is heated by the exhaust, forcing the oxygen ions to produce (energy) voltage. Deviations between the concentration of oxygen molecules in ambient air (drawn into the center cavity of the O2 sensor) and the concentration of oxygen ions in the spent exhaust gases, cause the heated oxygen ions inside the O2 sensor to jump between platinum layers very rapidly and repetitiously. Fluctuations in voltage occur as the rushing oxygen ions jump between the layers of the platinum electrodes. These variations in voltage are identified by the PCM as changes in exhaust oxygen concentration which indicate that the engine is either running lean (too little fuel) or rich (too much fuel). When more oxygen is present in the exhaust (lean condition), the voltage signal from the O2 sensor is low and is higher when less oxygen is present in the exhaust (rich condition). This data is used by the PCM primarily to calculate fuel delivery and ignition timing strategy but also to monitor catalytic converter efficiency. If the O2 sensor in question fails to cycle as rapidly and/or regularly as expected, over a set period of time and under certain predetermined circumstances, a P015B code will be stored and a malfunction indicator lamp may be illuminated. 

Other oxygen sensor delayed response trouble codes include: P013E O2 Sensor Delayed Response - Rich to Lean (Bank 1 Sensor 2) P013F O2 Sensor Delayed Response - Lean to Rich (Bank 1 Sensor 2) P014A O2 Sensor Delayed Response - Rich to Lean (Bank 2 Sensor 2) P014B O2 Sensor Delayed Response - Lean to Rich (Bank 2 Sensor 2) P015A O2 Sensor Delayed Response - Rich to Lean (Bank 1 Sensor 1) P015C O2 Sensor Delayed Response - Rich to Lean (Bank 2 Sensor 1) P015D O2 Sensor Delayed Response - Lean to Rich (Bank 2 Sensor 1) Code Severity & Symptoms Since a P015B code means that an O2 sensor has remained slow or unresponsive for an extended period of time, it should be categorized as severe. 

Symptoms of this code may include: Lowered fuel efficiency A general lack engine performance Other related diagnostic trouble codes may also be stored Service engine soon lamp illumination Causes Potential causes for this code to set are: Defective O2 sensor(s) Burnt, broken, or disconnected wiring and/or connectors Defective catalytic converter Engine exhaust leaks Diagnostic and Repair Procedures Some of the main tools that I would require to diagnose a code P015B are a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a reliable vehicle information source (All Data DIY). Before trying to diagnose a code P015B, all engine misfire codes, throttle position sensor codes, manifold air pressure codes, and mass air flow sensor codes must be diagnosed and repaired. An engine that is not running efficiently will cause all sorts of codes to be stored (and rightly so). Professional technicians typically start with a visual inspection of system wiring harnesses and connectors. We focus on harnesses that are routed near hot exhaust pipes and manifolds, as well as those that are routed near sharp edges like the ones found on exhaust shields. Search technical service bulletins (TSB) in your vehicle information source. If you find one that matches the symptoms and code/s presented by the vehicle in question, it will very likely aid you in your diagnosis. TSB listings are compiled from thousands of successful repairs. Next, I like to connect the scanner to the vehicle diagnostic port and retrieve all stored trouble codes and freeze frame data. This information may be helpful if the P015B proves to be intermittent so write it down for later. Now, clear the codes and see if the P015B is reset. If the code is reset, start the engine, allow it to reach normal operating temperature, and then let it idle (with the transmission in neutral or park). Use the scanner data stream to observe O2 sensor input data. Narrow the data stream display to include only pertinent data and you will see a faster and more accurate data response. If the engine is running efficiently, upstream O2 sensor data should fluctuate regularly between 1-millivolt (.100-volts) and 9-millivolts (.900-olts). If voltage fluctuations are slower than expected, a P015B will be stored. You can connect the DVOM test leads to the sensor ground and signal wires in order to monitor live data from the O2 sensor. You may also use it to check resistance of the O2 sensor in question, as well as voltage and ground signals. To prevent control module damage, disconnect related controllers prior to testing system circuit resistance with the DVOM. Additional diagnostic notes: Once the PCM has entered closed loop operation, downstream O2 sensors should not cycle as regularly as upstream sensors Low grade replacement (or remanufactured) catalytic converters are susceptible to repeated failure and should be avoided


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## snowwy66 (Nov 5, 2017)

Wondering how they got 4 injectors out of that printout. 

In the future. Buy yourself a bluetooth obd2 connector. There are cheap ones out there for $10. I don't recommend elm though. There's a really good one for $20. I'd have to go outside and look at the brand. It was highly recommended over the elm on a lot of forums. 

Torque App is free. And installs on your phone. You can use your phone as a code reader, and read some of the sensors and clear the codes.


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## memarciniak (Jun 29, 2018)

snowwy66 said:


> Wondering how they got 4 injectors out of that printout.
> 
> In the future. Buy yourself a bluetooth obd2 connector. There are cheap ones out there for $10. I don't recommend elm though. There's a really good one for $20. I'd have to go outside and look at the brand. It was highly recommended over the elm on a lot of forums.
> 
> Torque App is free. And installs on your phone. You can use your phone as a code reader, and read some of the sensors and clear the codes.


me TOO???? I don't see any injectors??? Thanks for the tip. I'll buy that tomorrow. hmy:


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## blackbird (Nov 6, 2017)

I'd second the idea that it sounds likely to be electrical related. If you have MAF, MAP/BARO and the O2 sensor all throwing codes there may be a problem somewhere in the wiring harness, a bad ground, or other electrical problem like a bad battery, alternator, or the common negative battery cable problem causing the voltage to drop and the computer sets a bunch of codes.

If it was a couple codes related to one sensor and it wasn't too expensive it might be worth swapping, but throwing a ton of different sensors and parts at the car may be a waste of money.


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## Robby (Mar 1, 2013)

To the OP........four fuel injectors do not fail at the same time. You have the title as the first member of this forum to replace one or more injectors. 
What I'm getting at is you are throwing money away.

This is what can happen by having your computer codes scanned and recommendations given by a outfit (auto zone in this case) that is in the business to sell......parts.

Now, back to your car......Currently you are describing a classic burst valve failure and the P0171 and the other fuel delivery codes are supporting this thought.
So, remove the upper cam cover (over the plugs/coil unit) and locate a circular(ish) cover cast into the cam cover. Start the engine. If the burst valve has failed you likely will hear a loud vacuum leak or hissing sound. There is a small hole cast into the disc housing. Put your finger over the hole......the hissing should now be gone and the engine will smooth out.
If this is the case, you at least will require the cam cover since the disc is not serviceable.

There is a strong possibility that if the disc failed the cause is a check valve failure that is part of the intake manifold. There is a inspection process.....search this site for it if your burst disc has failed.

Keep in touch.......stop throwing parts at it.

Rob


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## memarciniak (Jun 29, 2018)

Robby said:


> To the OP........four fuel injectors do not fail at the same time. You have the title as the first member of this forum to replace one or more injectors.
> What I'm getting at is you are throwing money away.
> 
> This is what can happen by having your computer codes scanned and recommendations given by an outfit (auto zone in this case) that is in the business to sell......parts.
> ...


I second that, it definitely could be vacuum related as Rob described. I also second the fact that nobody changes all the fuel injectors at one time. If an injector fails, it's usually just one. That's a lot of money and parts thrown at the problem.


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## Lazer (Feb 14, 2016)

You really trust any advice from someone at autozone?


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