If the ignition control module is bad on a 05 impala should the check engine light come on and show a code?

P0171 and P0174 are lean codes. There is likely a large vacuum leak or the MAF is bad.

Try starting the car and wiggling the connector for the MAF sensor. Also try tapping the MAF sensor. If the idle changes or the car stalls replace the MAF sensor.

The second shop should recognize that these codes don't have anything to do with the ignition module.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

To confirm the exact fault,the error code stored in engine computer module has to be retrieved.
But as why check engine light came up,for that issue there are few help link with solutions to correct the issue.========
Click the link below:---
After getting car washed, check engine light is ON and key less entry not working, tried reprogramming. Also car shows fuel pressure? http://schematicsdiagram.blogspot.com/2011/12/after-getting-car-washedcheck-engine.html
------------How to Read Codes from Check Engine Light? http://schematicsdiagram.blogspot.com/2011/12/how-to-read-codes-from-check-engine.html
------------Check Engine Light Reset Procedure? http://whoisbyme.blogspot.in/2012/06/check-engine-light-reset-procedure.html
------------- Check Engine Light ON? http://whoisbyme.blogspot.in/2012/06/check-engine-light-on.html
----------- Intermittent Check Engine Light? http://whoisbyme.blogspot.in/2012/06/intermittent-check-engine-light.html
---------- Service engine soon Light Turned OFF after Jump Start? http://whatisbyme.blogspot.in/2012/06/service-engine-soon-light-turned-off.html
---------- 2005 Chevy Impala: Service Vehicle Soon Warning Light? http://whoisbyme.blogspot.in/2012/06/2005-chevy-impala-service-vehicle-soon.html
--------- Malfunction Indicator Light ON http://whoisbyme.blogspot.in/2012/06/malfunction-indicator-light-on.html
--------- Car jerks while going uphill and Check engine light is ON?

http://schematicsdiagram.blogspot.com/2011/12/car-jerks-while-going-uphill-and-check.html

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Toyota Camry Check engine light flashes while driving? http://schematicsdiagram.blogspot.in/2012/02/toyota-camry-check-engine-light-flashes.html
----------1999 Toyota Tacoma: Check Engine Light Read Code P0171?

http://whatisbyme.blogspot.in/2012/05/1999-toyota-tacoma-check-engine-light.html
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2007 Toyota Highlander Hybrid: Yellow Check Engine Light ON dash? http://whatisbyme.blogspot.in/2012/05/2007-toyota-highlander-hybrid-yellow.html

--------Check engine light with codes P2195 and P2197? http://howtobyme.blogspot.in/2012/01/check-engine-light-with-codes-p2195-and.html
---------Car Runs Fine But Check Engine light is ON? http://whatisbyme.blogspot.in/2012/05/car-runs-fine-but-check-engine-light-is.html
----------After replacing throttle body the Check engine light starts blinking? http://technoanswers.blogspot.com/2012/01/after-replacing-throttle-body-check.html
---------OBD Code is cleared but check engine light will not RESET? http://schematicsdiagram.blogspot.in/2012/02/obd-code-is-cleared-but-check-engine.html
--------These will help.Thanks.

Hello
When the service engine soon light (Also called the check engine light or engine management light) is turned on this is to alert you to the fact that Powertrain Control Module (computer) has detected a failure somewhere in the systems it controls you may not feel any difference in the way the engine runs, this can be the transmission or the engine or emission system, there are fault codes set in the modules memory for these faults. What needs to happen now is to have the powertrain control module scanned with a special tool called an OBD2 electronic engine control scanner or a OBD2 code reader. Once the code(s) are read then you must perform the diagnostics for each code and make the appropriate repairs based on the findings of the diagnosis that was performed, this is called doing "Pinpoint" testing.

You'll have to figure out if it is a fuel or ignition problem.
Is the check engine light on ? Have you checked for trouble codes ?
It could be a relay, the ignition module, coil, fuel pump, or a list of other things.
Could even be a problem with the security system.

when turning the key to start and all the lights go off indicates a battery problem
could be dirty terminals and battery posts ( have to be shiny clean) and tight, bad ground wire to engine or bad cells in battery
it needs 12 volts to run the lights but when the starter is engaged the volts drop to below 6 volts , the lights go out

anybody else seen this happen ????? their are no magical fixes for automotive electrical problems . You buy yourself a DVOM - digital volt ohm meter an test all the electrical coming into the ignition switch an going out . Do you know how to do automotive elcetrical an electronic testing ? Do you know what voltage drop is ?
Electric Testing Techniques You Need to Know Do you know what a wiring diagram is ? You can find free ones here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model and engine size ! Under system click on electrical distribution , under subsystem click on power distribuition ! Click the search button then the blue link. Find the ignition switch , check power in an out when trying to start the vehicle , voltage drop ! ignition switch could be bad . Do a voltage drop test on the starting circuit , bad positive or ground cable .
Starter Voltage Drop
Relay Controlled Power Mode
The body control module (BCM) uses the discrete ignition switch inputs ignition 1, ignition 3 and crank to distinguish the correct power mode. Once the BCM has determined the power mode selected by the vehicle operator it will energize the Ignition relay, Run relay and retained accessory power (RAP) relay, depending on which power mode is selected.
Your getting into thing's you have no clue about , probably ! Do you know about computer controlled thing's

Ignition 1 Relay
The relay uses a Hot At All Times B+ power source derived from the underhood electrical center. The ignition 1 relay supplies a power signal to the following circuits when the Run or Crank power mode is selected:
• AC clutch relay
• ABS STG angle sensor
• Antilock brake system (ABS) yaw sensor
• Auxiliary power drop connector
• Crank relay
• Cruse control switch
• Electronic brake control module (EBCM)
• Engine control module (ECM)
• HVAC module
• Ignition control module (ICM)
• Instrument panel cluster (IPC)
• Sensing and diagnostic module (SDM)
• Transmission solenoid circuit
Power to many of this vehicle's circuits are controlled by the module that is designated the Power Mode Master (PMM). This vehicle's PMM is the Body Control Module (BCM). The PMM controls which power mode (Run, Accessory, Crank, Retained Accessory Power, or Off) is active.
Serial Data Power Mode
On vehicles that have several control modules connected by serial data circuits, one module is the power mode master (PMM). On this vehicle, the PMM is the body control module (BCM). The PMM receives 3 discrete ignition switch signals to differentiate which power mode will be sent over the Serial Data circuits. The table below illustrates the state of these inputs in correspondence to the ignition switch position:

The airbag light has absolutely noting to do with the engine starting unless it is because the airbag module is losing power at the same time that some engine component is losing power due to a defective ignition, battery, or ground circuit.

The best thing to do is to scan your computer network for possible fault codes that may lead you to the cause. Please note that I said "computer network", NOT engine control module. Most generic OBD code readers (like those used at many parts stores as a sales tool to sell you a bunch of stuff you don't need) cannot access anything but the continuous memory in the engine control module....you need to scan ALL modules.

try this install the new key in the ignition switch. turn on the ignition switch to the on position for 10 minutes.when the system led lock light disappear.turn off the ignition switch for 5 seconds.then start the engine.still dont start.try this procedure few more times.if car still dont crank and you see the pad lock symbols.the dealership will have to reprogram the new key and body control module.

COULD BE THE ACCELERATOR PEDAL POSITION SYSTEM CONTROL MODULE PERFORMANCE.OR PROBLEM IN THE POWER TRAIN OR TRANSMISSION CONTROL MODULE.HAVE CAR SCANNED AT AUTO ZONE THEY WILL DO IT FREE.TELL WILL TELL YOU YOUR CHECK ENGINE LIGHT CODE.

check intake for vaccum leaks,the gasket also and egr valve, thats alot of parts to have replaced without diagnosing first, if there are no fuel leaks and you said all injectors were replaced then you have a defective fuel pump, also these engines had misfire problem because of dirty injector but you replaced them so count that out. good luck.