2005 F150 5.4 Cuts off when driving at constant speed and show "Engine Fail Safe Mode" on display. It will crank back up and run for several hundred miles before doing it again. P2112 Throttle Air Control System Stuck Closed - P2104 Throttle Air Control System Force Idle - P0506 Idle Control System RPM Lower Than Expected & P0420 Catalyst Effeciency Below Threshold Bank 1 are the codes that I get. Is there a simple fix? Thanks

2004 cts ????? Cadillac cts ?
The body control system consists of the following 2 modules:
• The Dash Integration Module (DIM)
• The Rear Integration Module (RIM)
Each of the 2 body control modules integrate a number of functional systems. Each module is connected to the class 2 serial data circuit, many of the control signals are implemented by class 2 messages.
Dash Integration Module (DIM)
The various DIM input and output circuits are described in the corresponding functional areas as indicated on the DIM electrical schematics.
The DIM functions include the following:
• cigar lighter relay control
• class 2 communication requiring DIM interaction
• exterior lighting control
• headlamp washer control
• hood ajar switch input w/export
• horn relay control
• interior lighting control
• load management
• low side temperature for HVAC compressor
• park key lock output
• power moding control over Class 2 serial data circuit
• reverse lockout solenoid control
• steering wheel controls input
• storage of the clock settings and, sending a message out on the class 2 serial data circuit in response to requests from other modules
• storage of vehicle options and configuration
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 DIM. The PMM receives 2 signals from the ignition switch.
To determine the correct power mode the PMM uses the following circuits:

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 DIM. The PMM receives 2 signals from the ignition switch.
To determine the correct power mode the PMM uses the following circuits:
• Accessory voltage
• Run/Crank voltage
2-Wire Ignition Switch Table Ignition Switch Position
Accessory (Ignition Accessory/Run)
IGN 1 (Ignition Run/Crank)
Power Mode Transmitted
Off
0
0
OFF/Awake or RAP
Start
0
1
Crank
Accessory
1
0
Accessory
Run
1
1
Run
Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the PMM fail to send a power mode message. The fail-safe plan covers those modules using exclusively serial data control of power mode as well as those modules with discrete ignition signal inputs.
Serial Data Messages
The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid PMM message until they can check for the engine run flag status on the serial data circuits. If the PMM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to RUN. In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
Discrete Ignition Signals
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, battery positive voltage, the modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
Replacing either one of these module requires programming .
Program the module. Refer to Body Control Module (BCM) Programming/RPO Configuration
Are you sure you want to mess with these .

Could be ignition switch problem or a stuck closed relay . Gm has had ignition switch problems . Your best bet , if you don't know how to test automotive electrical systems , mite be to take it to a qualified repair shop. With the electronic's on your vehicle ,really ,it could anything .The BCM - body control module controls most of the vehicle .
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 BCM uses 3 signals from the ignition switch. These are the Ignition 0, Ignition 1, and Accessory.
To determine the correct power mode the BCM uses:
• The state of these signals
• The sequence of switch closures received by the BCM
• The status of the engine run flag

Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the body control module (BCM) fail to send a power mode message. The fail-safe plan covers modules with discrete ignition signal inputs as well as those modules using exclusively serial data control of power mode.
Serial Data Messages
The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid BCM message until they receive the engine status from the powertrain control module (PCM). If the BCM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is true, indicating that the engine is running, the modules fail-safe to Run. In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is false, indicating that the engine is not running, the modules fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
Discrete Ignition Signals
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid BCM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.

Have the ignition switch checked. First ck

What do you mean no sound when turning key ? Does the car start an run ? Or the car doesn't crank ? Ignition switch's do not work the same way they did in the old days , especially on GM vehicles . The ignition switch is an input to the BCM - body control module , the BCM processes these inputs an then energizes relays to turn things on . Also sends messages to other modules for them to turn on or energize relays .
The power mode signal may be as simple as a B+ input wired to a particular ignition switch contact. If this is also the B+ supply to the module/device, the module/device will only operate with the ignition contact closed to B+. An example of this is the starter relay when it is wired directly to the CRANK/START contact of the ignition switch. When the CRANK/START contacts are closed, the starter relay is energized and provides a current source to the starter and starter solenoid. When the ignition switch leaves the CRANK/START position, the switch contacts open and the starter relay is de-energized. This removes the current source from the starter and solenoid and the starter operation stops.
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 BCM receives 4 signals/circuits from the ignition switch. These are the Ignition 0, Ignition 1, Crank and Accessory 1 ignition switch signals/circuits.
To determine the correct power mode the BCM uses:
?€¢
The state of these signals/circuits, either switch closed (B+ = 1) or switch open (open = 0)

?€¢
The sequence of switch closures received by the BCM

?€¢
The status of the engine run flag.

Important: Any ignition switch states not covered in this table indicates a DTC setting situation.
The chart indicates the modes detected and transmitted by the BCM:
Power Mode Selected/Expected
Engine Run Flag Serial Data
Sampled Ignition Signal State
Power Mode State
Accessory
Ignition 0
Ignition 1
Crank
OFF-LOCK
0
0
0
0
0
OFF
Accessory
0
1
0
0
0
ACCESSORY
RAP
0
1 to 0
0
0
0
RAP
OFF-UNLOCK
0
0
1
0
0
UNLOCK
RAP
0
1 to 0
1
0
0
RAP-UNLOCK
Run
0
1
1
1
0
RUN
Crank
0
0
1
1
1
CRANK
Crank
1
0
1
1
1
CRANK
Run
1
1
1
1
0
RUN
Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the BCM fail to send a power mode message. The fail-safe plan covers modules with discrete ignition signal inputs as well as those modules using exclusively serial data control of power mode.
Serial Data Messages The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid BCM message until they can check for the engine run flag status on the serial data circuits. If the BCM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to "RUN". In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
Discrete Ignition Signals Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid BCM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the "RUN" power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to "OFF-AWAKE". In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
You probably won't understand any of this info. your best but would be to take it to a qualified repair shop that has proper diagnostic test equipment !

Ford Five Hundred idle speed adjustment Questions ... - Fixya

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Ford Five Hundred cars & trucks idle speed adjustment questions and answers. ... 2005 Ford 500 engine speed problem ... Question about 2006 Five Hundred.

Ford Electronic Throttle Body Failures - YouTube

? 3:26
www.youtube.com/watch?v=FDpUo3UPmto
Jan 10, 2014 - Uploaded by FordTechMakuloco Just to say I had a 2006 five hundred and cleaned that throttle at 98k, and worked ... I'm having to replace the throttle body in my 2005 Ford Freestyle - apparently a .... How to clean a throttle body and Idle air control valve (iac) ...

On GM vehicles starting back in mid 2000's , maybe even before that. They started using inputs to the body control module from the ignition switch, from there the BCM controls all vehicle systems .
Power Mode Description and Operation
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 BCM uses 3 signals from the ignition switch. These are the Ignition 0, Ignition 1, and Accessory.
To determine the correct power mode the BCM uses:
?€¢
The state of these signals

?€¢
The sequence of switch closures received by the BCM

?€¢
The status of the engine run flag

The chart indicates the power modes detected and transmitted by the BCM:

Correct Ignition Switch Inputs
Ignition Key Position

Power Mode Parameter

Engine Running

Sampled Ignition Signal State

Accessory

Ignition 1

Ignition 0
OFF
Off-Awake or RAP
No
Inactive
Off
Off
UNLOCK
Unlock or RAP Unlock
No
Inactive
Off
On
ACC
Accessory
No
Active
Off
On
ON
Run
No
Active
On
On
START
Crank
No
Inactive
On
On
ON
Run
Yes
Active
On
On
Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the body control module (BCM) fail to send a power mode message. The fail-safe plan covers modules with discrete ignition signal inputs as well as those modules using exclusively serial data control of power mode.
Serial Data Messages The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid BCM message until they receive the engine status from the powertrain control module (PCM). If the BCM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is true, indicating that the engine is running, the modules fail-safe to Run. In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is false, indicating that the engine is not running, the modules fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
Discrete Ignition Signals Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid BCM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, B+, the modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
You would need a scan tool that can read data from the BCM . What may be the problem is a lose connector , these pin's at connectors are tiny and doesn't take much for one to become lose.

You need to take it to a qualified repair shop that has the diagnostic tool to check DTC'S - diagnostic trouble codes . You have no idea of the complexity of the electronic's . All computer controlled . Do you know what serial data communications netwoking is ?
003 Communications Diagnostics
Moving the ignition switch to the START position sends a 12-volt signal to the engine control module (ECM) to command starting. Battery voltage also travels through the switch side of the Run/Crank relay then through the clutch switch, if equipped with manual transmission, and on through the coil side of the Starter relay and then to the ECM. The ECM receives class 2 information from the vehicle theft deterrent (VTD) and transmission control module (TCM) to verify that all parameters are met for starting. When all parameters are met the ECM grounds the control circuit of the Starter relay closing the switch providing battery voltage to the starter solenoid through a 30 A Maxi-Fuse.
012 GM Class II Communications
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 dash integration module (DIM). The PMM receives 2 signals from the ignition switch.
To determine the correct power mode the PMM uses the following circuits:
• Accessory voltage
• Run/Crank voltage
Fail-safe Operation
Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the power mode master (PMM) fail to send a power mode message. The fail-safe plan covers those modules using exclusively serial data control of power mode as well as those modules with discrete ignition signal inputs.
Serial Data Messages
The modules that depend exclusively on serial data messages for power modes stay in the state dictated by the last valid PMM message until they can check for the engine run flag status on the serial data circuits. If the PMM fails, the modules monitor the serial data circuit for the engine run flag serial data. If the engine run flag serial data is True, indicating that the engine is running, the modules fail-safe to RUN. In this state the modules and their subsystems can support all operator requirements. If the engine run flag serial data is False, indicating that the engine is not running, the modules fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.
Discrete Ignition Signals
Those modules that have discrete ignition signal inputs also remain in the state dictated by the last valid PMM message received on the serial data circuits. They then check the state of their discrete ignition input to determine the current valid state. If the discrete ignition input is active, battery positive voltage, the modules will fail-safe to the RUN power mode. If the discrete ignition input is not active, open or 0 voltage, the modules will fail-safe to OFF-AWAKE. In this state the modules are constantly checking for a change status message on the serial data circuits and can respond to both local inputs and serial data inputs from other modules on the vehicle.

2005 explorer showing engine fail safe mode and wrench

Fail safe is TPS sensor. When you go in fail safe the vehicle give a set amount of RPM and no throttle response the rule of thumb in fail safe is APP1 and APP2 does not agree the goal is to protect the catalytic convertor. So if the transmission was at fault you dont over rev to end up burning the Cat. Or over rev to break the engine It all boils down to a throttle body assembly as the solution

I do not know about a Jag. But the "fail safe engine mode " on my GMC means the Engine Controll Computer has quit working.