I disconnected my battery to replace the module for the directionals/wipers. When I re-connected the battery the "Limp Home" wrench light is on and the throttle does absolutely nothing. It's like it's not connected. Could there have been something in the steering column that I accidently disconnected?
'05 Town Car in Limp Home Mode
- Thread starter Joe in NY
- Start date
Anthony C
Registered
FYI ........Yes this is an old thread but here is the procedure ...
Ford throttle body relearn procedure
How to do a Ford throttle body relearn procedure
If you’ve replaced your Ford electronic throttle body or you’ve disconnected the battery, you must do a Ford throttle body relearn to establish a new baseline idle. Starting in early 2000’s, many car makers including Ford started installing fly by wire electronic throttle bodies. In those vehicles, the “gas” pedal isn’t connected to the throttle body by a cable. The pedal simply provides an electronic signal, telling the throttle body how much acceleration you’re requesting. A motor and gear reduction set inside the throttle body opens and closes the throttle plate to accomplish your request.
Over time, carbon buildup can accumulate around the throttle plate, changing it’s “home” position. If the buildup occurs gradually, the PCM “learns” the new home position. But when your battery goes dead or you disconnect it to work on your vehicle, the PCM “forgets” the adapted home position. If you don’t do a relearn procedure, the PCM will “hunt” for a new baseline idle. It will eventually learn it on its own, but it may take over a week of driving, during which time you will experience high and low idle speeds and possibly rough idle.
Here’s the throttle body relearn procedure
Clear the PCM adaptive memory
1) Disconnect the negative battery terminal.
2) Run a jumper wire from the positive battery cable to the now disconnected negative battery cable terminal. NOTE. Do this with the negative cable DISCONNECTED from the battery. The short circuit you’re creating here is designed to drain all power from the capacitors inside the PCM. Leave the jumper connected for about 2-mins.
3) Reconnect the negative battery cable to the battery.
Turn off all electrical accessories before proceeding. Turn off headlights, blower motor, radio, wipers, etc.
4) Turn the key to run and wait for all warning lights to turn off. During the period the PCM will command the throttle body plate to sweep from full open to full close to “learn” the new positions.
5) Start the engine and let it idle for a full 10-mins until it reaches full operating temperature. During this period the idle may be higher than normal. It should slowly drop as the engine heats up. Watch the engine temp gauge and note when it reaches operating temp. Then continue to let it idle for an additional 5 minutes. It will continue to adjust idle during this period.
6) Drive the vehicle at various speed so the PCM learns shift points.
Clean an electronic throttle body
How to perform an electronic throttle body cleaning
If you own a late model fuel injected vehicle, chances are it has an electronic throttle body. They can suffer from carbon buildup just like the older idle air control valve, so you may need to perform an electronic throttle body cleaning procedure. Over time, carbon buildup can accumulate around the throttle plate, changing it’s “home” position. Even though the PCM has learned new baseline home positions, the carbon interrupts the flow of air past the throttle plate. You’ll get a smoother idle if you perform a Ford electronic throttle body cleaning. Here’s how to do it.
WARNING: Do not do this while the throttle body is on the vehicle. An electronic throttle body is built with a powerful motor and a gear reduction set that’s strong enough to cut off your fingers. If you force the throttle plate open while the unit is on the vehicle, it will try to close and may cause injury.
1) Buy a new throttle body gasket, an aerosol can of throttle body cleaner, and a toothbrush. Do NOT use carburetor cleaner. The solvents in carb cleaner can damage
2) Find and label all small vacuum hoses going to the throttle body. If you don’t do that know, you may forget which ports they attach to. Use removable (blue) masking tape and number both the hose and the port using a sharpie marker.
2) Disconnect the air duct from the throttle body. Most air ducts are attached with worm drive clamps or plastic snap clamps. Undo the clamps first. Then check for any sensors in the air duct. If you find sensors, disconnect the electrical connectors and label them. If you can’t remove the clamps, leave this job to the professionals.
3) Disconnect the negative battery terminal to prevent accidental activation of the radiator fan.
4) Remove the electronic throttle body from the intake manifold and place it on shop rags on your workbench.
5) Wear rubber gloves for the following steps. Spray the underside of the Ford electronic throttle body throttle plate with cleaner
Remove carbon buildup from the bottom of the throttle plate
and let it soak. Don’t allow the solvent to seep into the electronics portion of the throttle body–it can damage the interior parts.
Then wipe off as much buildup as possible. Spray it again and use the toothbrush to scrub remaining buildup. Wipe again with a shop rag.
6) Spray the other side of the throttle plate and clean using the same technique.
7) Open the throttle plate and scrub the edge of the throttle plate.
Clean the edge of the throttle plate
8) Spray cleaner on a rag and wipe any carbon from the bore of the throttle body. Then spray both sides again and let it dry.
9) Re-install the Ford electronic throttle body with the new gasket. Torque the retaining nuts to spec.
Then perform the electronic throttle body relearn for your engine.
Ford throttle body relearn procedure
How to do a Ford throttle body relearn procedure
If you’ve replaced your Ford electronic throttle body or you’ve disconnected the battery, you must do a Ford throttle body relearn to establish a new baseline idle. Starting in early 2000’s, many car makers including Ford started installing fly by wire electronic throttle bodies. In those vehicles, the “gas” pedal isn’t connected to the throttle body by a cable. The pedal simply provides an electronic signal, telling the throttle body how much acceleration you’re requesting. A motor and gear reduction set inside the throttle body opens and closes the throttle plate to accomplish your request.
Over time, carbon buildup can accumulate around the throttle plate, changing it’s “home” position. If the buildup occurs gradually, the PCM “learns” the new home position. But when your battery goes dead or you disconnect it to work on your vehicle, the PCM “forgets” the adapted home position. If you don’t do a relearn procedure, the PCM will “hunt” for a new baseline idle. It will eventually learn it on its own, but it may take over a week of driving, during which time you will experience high and low idle speeds and possibly rough idle.
Here’s the throttle body relearn procedure
Clear the PCM adaptive memory
1) Disconnect the negative battery terminal.
2) Run a jumper wire from the positive battery cable to the now disconnected negative battery cable terminal. NOTE. Do this with the negative cable DISCONNECTED from the battery. The short circuit you’re creating here is designed to drain all power from the capacitors inside the PCM. Leave the jumper connected for about 2-mins.
3) Reconnect the negative battery cable to the battery.
Turn off all electrical accessories before proceeding. Turn off headlights, blower motor, radio, wipers, etc.
4) Turn the key to run and wait for all warning lights to turn off. During the period the PCM will command the throttle body plate to sweep from full open to full close to “learn” the new positions.
5) Start the engine and let it idle for a full 10-mins until it reaches full operating temperature. During this period the idle may be higher than normal. It should slowly drop as the engine heats up. Watch the engine temp gauge and note when it reaches operating temp. Then continue to let it idle for an additional 5 minutes. It will continue to adjust idle during this period.
6) Drive the vehicle at various speed so the PCM learns shift points.
Clean an electronic throttle body
How to perform an electronic throttle body cleaning
If you own a late model fuel injected vehicle, chances are it has an electronic throttle body. They can suffer from carbon buildup just like the older idle air control valve, so you may need to perform an electronic throttle body cleaning procedure. Over time, carbon buildup can accumulate around the throttle plate, changing it’s “home” position. Even though the PCM has learned new baseline home positions, the carbon interrupts the flow of air past the throttle plate. You’ll get a smoother idle if you perform a Ford electronic throttle body cleaning. Here’s how to do it.
WARNING: Do not do this while the throttle body is on the vehicle. An electronic throttle body is built with a powerful motor and a gear reduction set that’s strong enough to cut off your fingers. If you force the throttle plate open while the unit is on the vehicle, it will try to close and may cause injury.
1) Buy a new throttle body gasket, an aerosol can of throttle body cleaner, and a toothbrush. Do NOT use carburetor cleaner. The solvents in carb cleaner can damage
2) Find and label all small vacuum hoses going to the throttle body. If you don’t do that know, you may forget which ports they attach to. Use removable (blue) masking tape and number both the hose and the port using a sharpie marker.
2) Disconnect the air duct from the throttle body. Most air ducts are attached with worm drive clamps or plastic snap clamps. Undo the clamps first. Then check for any sensors in the air duct. If you find sensors, disconnect the electrical connectors and label them. If you can’t remove the clamps, leave this job to the professionals.
3) Disconnect the negative battery terminal to prevent accidental activation of the radiator fan.
4) Remove the electronic throttle body from the intake manifold and place it on shop rags on your workbench.
5) Wear rubber gloves for the following steps. Spray the underside of the Ford electronic throttle body throttle plate with cleaner
Remove carbon buildup from the bottom of the throttle plate
and let it soak. Don’t allow the solvent to seep into the electronics portion of the throttle body–it can damage the interior parts.
Then wipe off as much buildup as possible. Spray it again and use the toothbrush to scrub remaining buildup. Wipe again with a shop rag.
6) Spray the other side of the throttle plate and clean using the same technique.
7) Open the throttle plate and scrub the edge of the throttle plate.
Clean the edge of the throttle plate
8) Spray cleaner on a rag and wipe any carbon from the bore of the throttle body. Then spray both sides again and let it dry.
9) Re-install the Ford electronic throttle body with the new gasket. Torque the retaining nuts to spec.
Then perform the electronic throttle body relearn for your engine.
