What's causing a Catalyst code?
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Junior User
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From: Minneapolis
What's causing a Catalyst code?
On my '96 Aerostar 4.0L I'm not getting a trouble code but a yellow "warning" code that indicates the catalyst monitor. Is that indicating a problem with the catalytic converter or are there other items that might be associated?
Former ******
Joined: Nov 2004
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From: Salt Lake City, Utah
Catalyst failure indicates one or more of several possibilities. Either the catalyst has been damaged by excessive fuel, oil, antifreeze, sulpher, or other engine fluid entering th exhaust/ the catalst has been physically damaged/ there is a leak in the exhaust system somewhere upstream of the rear O2.
Most of the time, this does indicate the catalytic converter is somehow not working, but why it failed should always be identified. I would try some Seafoam, and decarbon the engine, that may help remove some contaminants enough to restore function. I would also replace the rear O2, since it is less expensive than a converter installed.
Most of the time, this does indicate the catalytic converter is somehow not working, but why it failed should always be identified. I would try some Seafoam, and decarbon the engine, that may help remove some contaminants enough to restore function. I would also replace the rear O2, since it is less expensive than a converter installed.
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Junior User
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From: Minneapolis
I did use Seafoam through the brake booster that same evening, but nothing changed regarding the code. Question- would a new rear O2 improve this situation or is a new catalytic converter on the horizon? I hope not because the exhaust is all in very good condition. Or so it seems...
Post Fiend
Joined: Oct 2005
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From: Kiev, Ukraine
May be, but to be sure, try a detailed emmision test.
And remove spark plugs and look at them.
Too much CO - reach mixture, too much CxHx - missfire, lean mixture ore bad plugs, NOx - bad cat. converter, but sometimes all this problems may be becouse of bad O2 sensor, bad MAF, IAC ore ECT.
Read atual values in OBD-II data ore use DAVOM if U have EEC-IV model and compare it with tabels on http://fordfuelinjection.com/?p=10. Read this data on idling engine and on 2000 rpm.
I have OBD-I aero with MAP sensor. Unfortunatly to learn what a MAP I have to use osciloscope..... But all other sensors may easily ne checked with DAVOM.
And remove spark plugs and look at them.
Too much CO - reach mixture, too much CxHx - missfire, lean mixture ore bad plugs, NOx - bad cat. converter, but sometimes all this problems may be becouse of bad O2 sensor, bad MAF, IAC ore ECT.
Read atual values in OBD-II data ore use DAVOM if U have EEC-IV model and compare it with tabels on http://fordfuelinjection.com/?p=10. Read this data on idling engine and on 2000 rpm.
I have OBD-I aero with MAP sensor. Unfortunatly to learn what a MAP I have to use osciloscope..... But all other sensors may easily ne checked with DAVOM.
Former ******
Joined: Nov 2004
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From: Salt Lake City, Utah
Since the Seafoam did not clear the problem, let me give you the standard procedure to clear up this issue and prevent repeated catalyst failures. Skip anything that you already did recently.
1: Replace both O2 sensors amd perform a tune up.
2: Replace catalyst. While it is out, inspect it to determine the cause of failure.
3: Replace any and all parts needed to clear any additional stored codes. Make certain that antifreeze, oil, or raw fuel is not entering the exhaust.
4: Decarbon the engine.
1: Replace both O2 sensors amd perform a tune up.
2: Replace catalyst. While it is out, inspect it to determine the cause of failure.
3: Replace any and all parts needed to clear any additional stored codes. Make certain that antifreeze, oil, or raw fuel is not entering the exhaust.
4: Decarbon the engine.
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From: Minneapolis
Finally a code
Well, the code finally went "red" and I got a P1443, which is either the Purge control valve or Purge control solenoid associated with the evaporative canister. How do you test the solenoid to determine if it's still good? Voltmeter? 
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Former ******
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From: Salt Lake City, Utah
I would test the solenoid by applying 12 volt power to it. If it doesn't work, then it needs to be replaced. If it does work, check the wiring and see if it has been damaged. Corrosion inside a connector could cause the solenoid to stop responding as well.
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If you test the solenoid by applying 12v directly, make sure you keep the polarity correct. Some of these solenoids have a reverse biased diode across the coil to absorb back EMF. The coil doesn't care for the polarity, but if you apply the voltage to the diode in th wrong direction (forward bias), it will blow up, and you will have to buy a new solenoid.
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