2000 gran Marquis speedometer drops to 0 and check engine light is on. Will replacing speed sensor get it to pass emissions?

SOURCE: 2002 pontiac grand am 4 cylinder sedan cant pass emissions

not enough information so i will cover many possibilities:

new spark plugs would be a good place to start .. then replace the ignition wires, clean the coil insulator .. clean or replace the distributor cap .. when you replaced the O2 sensor that should have eliminated the "heater circuit" problem (the O2 sensor has a built in heater that gets it up to working temprature faster at warm up) .. .. if the wiring and connectors to the O2 sensor are ok then that fault code should go away .. multiple misfires will keep the trouble light on .. that could also be caused by a sticking or dirty injector or dirty throttle body.. you can use a good injector cleaner for that .also look for a cracked vacuum hose ... it would be good to know the present fault code since it should have changed once you installed the new O2 sensor .. there may be two O2 sensors (one later in the exhaust system) ..it sounds like you got the right one but make sure ..it may take some time for the computer to adjust to the new O2 sensor and for the injector cleaner to work .. make sure new plugs are gapped properly and use an "antiseize" compound on the threads .. that reduces the probability of the plugs sticking in their sockets .. on aluminum heads the plugs want to seize (or weld) in place after a long time. .. that makes them really hard to get out later .. just a tiny amount of antiseize compound on the theads helps a lot .. be careful not to overrtighten plugs in aluminum heads ..
if your engine is badly missing on one cylinder (you should easily detect that) then a sticking injector would be suspect .. there are some simple ways to get it working again if thats the case ..

SOURCE: speedometer intermittently stops working

your ABS module (board) is crack and a good fixman could check that to fix or change it

PAUL MC G

• 1280 Answers
• Posted on Oct 18, 2009

SOURCE: Having the same problem the other guy described.

First of all, these codes are what are called "Powertrain Trouble Codes' (that's what the "P" means P=Powertrain). TCM Request (Transmission Control Module = TCM). The request was to turn on the 'Check Engine" light.
P0720 - output speed sensor circuit malfunction
P0715 - Input speed sensor (turbin speed) circuit malfunction
P0442 - Evaporative Emission System Leak (Small Leak)
P0455 - Evaporative Emission System Leak (Large Leak)
Check fuel filler cap problems - for Evap Emiss leaks
Replace the pulse generators & have the trans fluid replaced/flushed.
The Main Catalyst System Efficiency Bank 1 Is P0420, not P0442
If you had P0420 code, the catalytic converter is shot... and that's an expensive component.

SOURCE: 2001 Honda - New Catalytics & O2 sensors -- new 0420/1739/1456

I would send the car for a smoke test for the emissions leak...Find out where the leak is comming from..Repair it..Reset the codes, then do a drive cycle and see what happens...

Jeffrey Turcotte

• 8991 Answers
• Posted on Dec 13, 2010

SOURCE: 2000 dodge durango speedometer stoped

The below test is generic, but gives you a general idea how to test the sensor. Most shops skip to the resistance test (at the bottom), if they do any test at all. A new sensor is $17 at autozone. Let me know if you have any questions.

A defective vehicle speed sensor may cause different problems depending on the computer output control functions. A defective vehicle speed sensor (VSS) may cause improper converter clutch lockup, improper cruise control operation, and inaccurate speedometer operation.

• Prior to VSS diagnosis, the vehicle should be lifted on a hoist so the drive wheels are free to rotate.
• Backprobe the vss output wire and connect the voltmeter leads from this wire to ground.
• Select the 20-volt AC scale on the voltmeter.
• Then start the engine.
• Place the transaxle in drive and allow the drive wheels to rotate. If the VSS voltage signal is not 0.5 volt, or more, replace the sensor.
• When the VSS provides the specified voltage signal, backprobe the VSS terminal at the PCM and repeat the voltage signal test with the drive wheels rotating.
• If 0.5 volt is available at this terminal, the trouble may be in the PCM (powertrain control module).
• When 0.5 volt is not available at this terminal, turn the ignition switch off and disconnect the wire from the VSS to the PCM.
• Connect the ohmmeter leads across the wire. the meter should read zero ohm.
• Repeat the test with the ohmmeter leads connected to the VSS ground terminal and the PCM ground terminal.
• This wire should also have zero ohm resistance. If the resistance in these wires is more than specified, repair the wires.
• The condition of a speed sensor can be checked by going through the diagnostic routines for the system.
• If this test indicates that a sensor is faulty, the sensor should be replaced.
• Speed sensors can also be checked with an ohmmeter. Most manufacturers list a resistance specification.
• The resistance of the sensor is measured across the sensor's terminals.
• The typical range for a good sensor is 800 to 1400 ohms of resistance