code ?????s

Are you sure you need the downstream O2 sensor??? The downstream sensor monitors catalytic converter efficiency..... To have both fail at the same time is truly coincidence. IIRC, the strategy is to compare upstream O2 activity to downstream activity - since the exhaust has been processed by the converter, we expect to see very little activity on the downstream sensor.... when the converter fails, the PCM will report "excess activity" on the downstream sensor. That simply means that the PCM has seen excess activity and not that the O2 sensor has failed.

"Phony" diagnostic procedures are the only way we can avoid replacing parts needlessly...... to me, it looks like your shop will be damned if they do and damned if they don't. One of the things the shop gets paid for is knowing which side is bank one and which side is bank two...

Nobody "tried" to charge you anything... I assume you were offered an estimate for repairs and that there are other items on the estimate bringing the total to $2200. In a freemarket system, you are allowed to get other estimates. Incidentally, when we replace a catalytic converter, it is important to determine the cause of failure to avoid a repeat performance... doing so would be the sign of a good shop and good shops aren't cheap......... however, if you feel you deserve second rate work, don't let me hold you back....

BTW, bank 2 is the drivers side... the O2 problem an be verified by swapping sensors (no, not just the leads) but you will have to drive enough for the catalyst monitor to complete (more uncommon knowledge that the shop charges for). Seems to me that some states might even flunk you for a P1000 - more driving required to complete monitors.

Jim Warman being a dick about it all snipped-for-privacy@telusplanet.net

You've helped me out before Jim and therefor I will not be upset at you for that scathing response and you also did help me out again this time though I'm not convinced you meant to. In my defence the reason I say they tried to overcharge me is how do you justify charging $533 in parts (not including labor) for 4 O2 sensors when at their most expensive they are $60 each? Not to mention, that codes show only one bad O2 sensor. And all these as you call them "phony" tests are after the parts are replaced therefor I don't see how they would determine which parts are bad as they have already been replaced. I'm not a complete fool and I know when I'm being taken for a ride and this last one has got me a bit queesy. I've had first rate work on on parts much more difficult (i.e. transmission) that came at a lower pricetag then this "first" rate work. I understand you must hear allot of people complaining being in the business you are in but you know as well as many others do out there that there are shops that make a living overcharging and gouging especially if they know they have you over a barrel. These shops ruin the reputation and credibility of honest shops and people should be warned of this. Having said all that, thank you for your help Jim, especially since I know very well you don't earn a penny for it. Armed with the information you gave me I can go get another estimate from another shop in this great freemarket system and have a finer tuned bullshit meter when I'm there.

thanks,

John

P.S. as for the more driving required to complete monitors part, I put on

36K a year I think I drive it enough.

"Jim Warman" wrote in message news:F6b0c.111039$Hy3.107927@edtnps89...

performance...

John, you should realize by now that I can be a real dork when I want.....

You didn't mention that they were flogging 4 O2s - now that rates as a problem, in my book. I can't be sure that climatic differences can have an affect on sensor life, but I know that I've changed less than a handful of sensors since the mid-80s. If they have totally gone south (silicon poisoning or what have you) and they still show good activity, I see no reason to change them. I can now see why your alarm bells are ringing.

So the toss up now is whether the downstream O2 is pooched or the converter...... and that's where you can swap O2s around. IIRC, all four of yours are the same (compare wire lengths and hardshell colours to be sure - at the very least, the two downstreams will interchange). They come out easier when the exhaust is hot - sometimes a 7/8ths line wrench works better than the special socket... If the problem follows the sensor, change the sensor... if the problems stays put, change the converter...

BTW, even shops should use this, when needed, as a low cost diagnostic procedure...

Jim Warman snipped-for-privacy@telusplanet.net

No harm no foul Jim. I'll have a go at what you mentioned. The print-out I got from the EPA station cites codes P0153 and P0430. Maybe you can make odds and ends of it.

Thanks again,

John

FWIW, factory OBD-II manual says

PO153 - Upstream Heated Oxygen Sensor HO2S 21 (passenger side upstream sensor) circuit slow response.

P0430 - Catalyst system efficiency below threshold Bank #2

I had a P0153 >No harm no foul Jim. I'll have a go at what you mentioned. The print-out I

Chances are you don't have a bad cat. If you can get the front O2 sensor for $60 it's probably worth changing it out...or even both front O2s. If you clear the fault codes by disconnecting the battery make sure you check that the readiness codes are set so that the vehicle can get throught smog check. If you take the vehicle in immediately after a code clear (battery disconnect) you will fail the test.

Tom

'> ... The print-out I '> got from the EPA station cites codes P0153 and P0430. Maybe you can make '> odds and ends of it. ' 'Chances are you don't have a bad cat. If you can get the front O2 'sensor for $60 it's probably worth changing it out...or even both 'front O2s. If you clear the fault codes by disconnecting the battery 'make sure you check that the readiness codes are set so that the 'vehicle can get throught smog check. If you take the vehicle in 'immediately after a code clear (battery disconnect) you will fail the 'test. ' 'Tom ================================================

Thanks Tom, a couple of quick questions in this context.

How to make sure the readiness codes are set?

How long does it take after battery disconnect and code clearance for the readiness codes to set and what to do to have this happen?

Thanks again

Matt

You need a scan tool to check readiness status. You may be able to get the smog check station to verify readiness is set with a scan tool before they put the truck on the dyno and run the smog test procedure. It only takes a minute. Else, I hear Autozone offers free scan tool hookups at their stores. You just need to make sure the person who checks for readiness status knows what to look for.

The time required to set readiness codes after a battery disconnect could be one day or one month; it all depends on how you drive the truck. The most difficult readiness bit to set will be the EVAP monitor. That's the monitor that checks for leaks in the fuel tank. The EVAP monitor will usually require a cold start followed by a steady cruise. Each model/make is different but the generic advice for setting readiness is "by driving the vehicle for several days under a variety of normal conditions."

The good news is that you can still get by the smog check program with

2 or less unset readiness bits - that is if you live in California...I'm not sure what other states are requiring for readiness bits. So if you can verify with a scan tool that all OBD II monitors have run with exception of 2, 1, or 0, then your truck is ready to be taken in for testing; providing the Check Engine Light isn't on or pending codes are not present.

Hope this helps,

tom

'You need a scan tool to check readiness status. You may be able to 'get the smog check station to verify readiness is set with a scan tool 'before they put the truck on the dyno and run the smog test procedure. ' It only takes a minute. Else, I hear Autozone offers free scan tool 'hookups at their stores. You just need to make sure the person who 'checks for readiness status knows what to look for. ' 'The time required to set readiness codes after a battery disconnect 'could be one day or one month; it all depends on how you drive the 'truck. The most difficult readiness bit to set will be the EVAP 'monitor. That's the monitor that checks for leaks in the fuel tank. 'The EVAP monitor will usually require a cold start followed by a 'steady cruise. Each model/make is different but the generic advice 'for setting readiness is "by driving the vehicle for several days 'under a variety of normal conditions." ' 'The good news is that you can still get by the smog check program with '2 or less unset readiness bits - that is if you live in 'California...I'm not sure what other states are requiring for 'readiness bits. So if you can verify with a scan tool that all OBD II 'monitors have run with exception of 2, 1, or 0, then your truck is 'ready to be taken in for testing; providing the Check Engine Light 'isn't on or pending codes are not present. ' 'Hope this helps, ' 'tom

Thanks, Tom, for the detailed explanation.

Yes, Autozone does check the codes for free, I have seen them check for codes on my Explorer 2000 several times (trying to diagnose rough idle). As I stood there watching, once the scan tool establishes communication, it displays 'no codes'. I never saw it display anything else (my check engine light has never been on).

Does 'no codes' means readiness codes are set, OR scan tool has to be in a different mode to check for readiness codes? (how could I help the Autozone guy if he does not know how to look for readiness codes ?)

I am in PA, the new emissions check system introduced this year is publicized as consisting of 'OBD Check' and 'Gas Cap Check' there is NO dyno involved. I do not know technically what could they get out from OBD if the check engine light has never been on, on a vehicle?

Could you kindly educate us as to the above noted issues.

As always, Thanks in advance.

Matt

==========================================

Depending on the scanner that AutoZone uses, it will likely display a brief message during the initial scan. I believe AutoZone uses the AutoXray scanner (I have the same one). If they do then during the initial scan it will display whether or not the readiness checks have ben completed or not just before it starts scanning. Just watch the display when they press "scan".

To complete the Ford OBD-II readiness checks on my '97 here is what my manual has to say: "If the vehicle's powertrain system or its battery has just been serviced, the OBD-II system is reset to a "not ready for I/M test" condition. To ready the OBD-II system for I/M testing, a minimum of 30 minutes of city and highway driving is necessary as described below:

1) First, at least ten minutes of driving on an expressway or highway. 2) Next, at least twenty minutes driving in stop and go, city type traffic with at least four idle periods.

Allow the vehicle to sit for at least 8 hours without starting the engine. Then, start the engine and complete the above driving cycle. The engine must warm up to it's normal operating temperature. Once started, do not turn off the engine until the above driving cycle is complete."

You hit the nail on the head here. To check readiness you need to put the scan tool in a different mode than when checking for fault codes. Some scan tools do not give the option to check for readiness status. These are usually the ones that cost $70 or less. I have never seen the scan tools that Autozone uses so I'm not sure if they can check readiness status.

According to PA DEP website

to pass smogcheck in the state of PA: no more than 2 "unready" monitors areallowed for model years 2000 or older; and no more than 1 "unready"monitor is allowed for model years 2001 and newer. The reasoning behind readiness status is as follows: Let's say someone has a malfunction on their vehicle that turned on the MIL; this vehicle would fail an OBD II based smog check program. By disconnecting the battery or using a scan tool you can erase all OBD II fault information in the vehicle's computer and turn off the MIL. So if someone did not want to fix their vehicle they could simply clear codes just before a smog check and pass the OBD II portion of the inspection. Here's where readiness status comes in. The readiness status is also checked during a smog checked to catch (fail) vehicles that have recently had their fault memory cleared. When the fault memory is erased, the readiness status is also set to "not ready". If your vehicle has more than two monitors that are "not ready", the vehicle will fail smog check.

The readiness status will change from "not ready" to "ready" after a given monitor has run and passed. As stated earlier, this could take one day or up to one month. Readiness status is attched to most of the critical monitors: i.e., EVAP, CAT, O2, AIR, EGR...

For the gas cap check the inspector will remove the gas cap from the vehicle and screw it to the analyzer to pressure test the integrity of the gas cap seal.

hope this helps,

tom