Repair 7

The dash pad on a 2004 Chevrolet Silverado is also called the upper instrument trim panel. This panel runs the entire length of the passenger cabin and must be removed in order to access the gauge cluster and the interior ventilation ducts. This panel also contains the passenger-side assist handle and covers the upper portion of the passenger air bag unit. All 2004 model year Silverados contain this panel, despite their seating or cab configuration.

Instructions

Removal

1

Set the parking brake and turn the air flow control to the vent position. Move the gear selector lever, if equipped with an automatic transmission, to first gear to allow more space between the shift lever and the trim panel. Depress the tilt lever on the steering wheel and tilt the wheel as far down as it will go.

2

Pry off the end panel between the drivers door and the dashboard with a flat-head screwdriver. Pry off the end panel between the passenger door and the dashboard with a flat-head screwdriver. Pry off the instrument panel cluster trim plate bezel with a flat-head screwdriver.

3

Pry the right-side air vents out of the dashboard with a flat-head screwdriver. Insert a flat-head screwdriver through the duct outlet holes and depress the release tabs for the assist handle, then remove the assist handle.

4

Pry the windshield A-pillar moldings away from the pillars until they pop loose with a flat-head screwdriver. Remove the A-pillar moldings. Remove the bolts holding the trim panel to the supporting skeleton underneath the dashboard with a metric socket and a ratchet.

5

Lift up on the trim panel with both hands until the self-contained locking clips pop loose. Disconnect the ambient light sensors electrical connector and then completely remove the upper instrument trim panel from the vehicle.

Installation

6

Reconnect the ambient light sensors electrical connector to the underside of the instrument panel and set it into position. Press down on the panel to seat the panels integrated locking clips.

7

Reinstall the screws holding the trim panel to the dashboard skeleton with a ratchet and a metric socket. Torque the screws to 18 inch-pounds with a torque wrench.

8

Set the A-Pillar moldings into place and press them down until they snap into position on top of the A-pillar skeletons

9

Set the assist handle into position in front of the dash panel and press down on it until it locks into place. Pull on the handle to confirm that it is securely locked into place.

10

Place the vents into position in the air ducts and press down on them until they click into position. Snap the dashboard end panels into position.

11

Snap the instrument panel trim plate bezel into position. Tilt the wheel back to a normal position and shift the gear selector lever, if equipped, back into park.

Oxygen sensors have two basic functions: upstream sensors close to the manifold meter the amount of oxygen and burned fuel mixture in the exhaust; downstream sensors located near the catalytic converter monitor the catalyst efficiency. If too much fuel or too much oxygen is read by the sensor, it transmits the information via radio signal to the PCM, which then makes adjustments in the engine to correct the problem. Oxygen sensors wear out after a while and need to be replaced during regular maintenance schedule intervals.

Finding the Right Sensor

The hardest part of replacing an oxygen sensor is locating the correct one. Vehicles nowadays have at least two, but some can have up to four sensors. When the sensor fails to transmit or a noticeable problem in the fuel mixture is detected, the PCM will trigger the "check engine" light to alert the car owner that there is a problem. All vehicles built after 1996 have universal PCM plug-in sources called "DLCs," or "data link connectors." A scan tool or code reader will allow you to find out the problem or narrow it down by plugging it in to the DLC and then reading the code. But what if it says something like, "circuit failure sensor 1 bank 2?" Banks and sensor numbers are used to help identify the location of them in the exhaust system. "Sensor 1" indicates a forward or upstream sensor towards the manifold; "banks" indicate the split in the exhaust system, such as a Y-pipe coming off the engine or a genuine dual exhaust system. Bank 1 is most often located on the same side of the vehicle--left or right--as the number one cylinder. So sensor 1 bank 2 would be located upstream near the manifold on the opposite side of the number one cylinder.

Access

Access to some of the sensors nowadays is somewhat challenging. Most vehicle manufacturers place the oxygen sensors in conspicuous places that can easily be accessed. Others may make you wonder what they were thinking when they designed the exhaust system. There are tools to help make it easier for you and a trick or two that might work. Once youve located the correct sensor or sensors, unplug the sensor from the wire harness.

Tools

Oxygen sensor wrenches or sockets are available in most parts stores nowadays. Although they make the job a whole lot easier, theyre not magic wands. Limited access is still going to challenge you, and corrosion on the old sensor and exhaust pipe may be another obstacle. Remove the sensor once youve gotten the tool onto it by turning the tool counterclockwise. A degree of force will be required, but if it doesnt feel like its going to budge, heating up the portion of the exhaust pipe that surrounds the threads of the oxygen sensor might help. This can be done with a portable propane torch. Dont heat the sensor as well. Youre goal is to expand the exhaust pipe and not the sensor. Being careful not to burn yourself, retry removing the sensor with the wrench or socket until youre successful. If you dont have a torch, try running the car long enough to heat the exhaust system up for a while and then liberally spray lubrication oil on the sensor.

Replacement Sensors

Replacement sensors range in price from $50 to $120 a piece. Bosch makes a decent direct-fit aftermarket sensor made specifically for most vehicles at an affordable price. The dealership will sell direct-fit original equipment sensors, but will be on the high end of the price range. You may discover in your hunt for the best price that a universal sensor is available for many cars. This means the sensor can be wired in and used in more than one application non-specifically. Although its cheaper and sounds like a good deal, keep in mind that in addition to removing and replacing the oxygen sensor, youre going to have to cut and splice wires--that most likely will not color-code the same way on both ends. For a few dollars more, your money will be well spent for a name-brand direct-fit oxygen sensor made specifically for your vehicle.

In 1953, Ford slightly redesigned its F-series pickups and in the process revamped the names of the F-series trucks; the F-1, F-2 and F-3 became the F-100, F-250 and F-350, respectively. The 2006 Ford F-250 had three engines available, but it came standard with a 300-horsepower, 5.4-liter V-8 engine. This engine, as with all modern automotive engines in the U.S., came fitted with a catalytic converter, which converts harmful gases in the exhaust to harmless ones. Replacing the catalytic converter on the base level 2006 F-250 is a straightforward task

Instructions

Removal

1

Allow the vehicle to sit until the engine is cool to the touch, then allow it to sit for an additional hour to allow the catalytic converter to cool, as the converter typically is significantly hotter than the rest of the exhaust and retains heat more effectively.

2

Kick wheel chocks behind the rear wheels and raise the front of the F-250 with a floor jack. Slide jack stands under the frame rails and lower the vehicle onto the jack stands.

3

Crawl under the middle of the truck until you have a clear view of the catalytic converter.

4

Remove the four catalytic converter-to-Y-pipe nuts, using a ratchet and socket. If the nuts are seized, spray penetrating oil onto them and wait for the amount of time the oils instructions prescribe.

5

Loosen the clamp securing the intermediate pipe to the catalytic converter pipe using a ratchet and socket.

6

Trace the wiring for the catalyst monitor, the oxygen sensor on the catalytic converter, upward until you reach where its harness connects to the F-250s harness. Unplug the sensors harness from the F-250s harness.

7

Press the rubber catalytic converter hanger from the catalytic converters bracket. Press the converter rearward until the converter-to-Y-pipe studs are free from the Y-pipe, and lower the front part of the catalytic converter. Slide the catalytic converters pipe from the intermediate pipe and remove the converter from the truck.

8

Remove the catalyst monitor, the oxygen sensor on the catalytic converter, using a ratchet and oxygen sensor socket.

Installation

9

Apply a thin coating of an anti-seize compound to the catalyst monitors threads and hand-tighten the monitor into the new catalytic converter. Tighten the catalyst monitor to 34 foot-pounds using a torque wrench and oxygen sensor socket.

10

Scrub the mating surface on the Y-pipe with a wire brush. Guide a new catalytic converter-to-Y-pipe gasket onto the mating surface on the catalytic converter. Clean the mating surface on the inside of the intermediate pipe with emery cloth.

11

Lift the catalytic converter into place and press its bracket through the hole in the converters rubber hanger. Guide the convertor-to-Y-pipe studs through the bolt holes in the Y-pipe. Hand-tighten the four converter-to-Y-pipe nuts onto the studs.

12

Guide the rearmost pipe on the catalytic converter into the intermediate pipe. Move the intermediate pipe-to-catalytic converter pipe clamp so its within 0.15 inches of the end of the intermediate pipe and the bolt is at a 90-degree angle relative to the slots cut in the end of the pipe.

13

Tighten the convertor-to-Y-pipe nuts to 30 foot-pounds using a ratchet and socket, and tighten the intermediate pipe-to-catalytic converter pipe clamp to 41 foot-pounds.