My daughter is home from college for the holidays. She and a friend set out in the driving rain for a town two hours away in Bertha, and Bertha let them know she wasn’t too pleased with that.
Actually, Bertha (our 2007 Mercedes S550) ran just fine, but the check engine light came on and stayed on. My daughter called me from the road, but I told her if it was running OK, then it should be fine to keep going.
The next day, I started the car and the light stayed on. So, I got out my trusty Bosch code reader and took some pictures to share with you all.
Many of you I am sure have such a reader, but if you don’t they are well worth the price. They have come down in cost significantly. This one was about $70 on eBay, new in the box. It is a universal type, so it reads the basic codes that are universal to all cars built after 1996.
If it recognizes your car, it will read additional codes specific to that make and model. It recognized Bertha, here.
It first looks for codes. I would assume the check engine light would not come on without a code, but it’s also possible the light would eventually reset with a code still being “stored” in the system.
Using the keys on the reader, we highlight the code and ask to read it out. I don’t recall getting this code before. Google tells me that “PO432” can be caused by many things, but most likely is a failing catalytic converter that results in the converter not working as well as it should. With 11 years and 204,000 miles under her belt, Bertha’s converters may well be checking out on us.
If there was a second code for an oxygen sensor, then that would be the likely culprit. But without an oxygen sensor code, there’s probably no reason to start throwing parts at her.
I also wasn’t too concerned as she just passed the State emissions test the weekend prior to the check engine light coming on. I doubt there has been some catastrophic failure of the catalyst since last Saturday. It may not be working perfectly, but it’s apparently working well enough to pass emissions.
Our tag renewal sticker has already been issued, so we are legal until Jan. 15, 2019 regardless.
I reset the light, and it has stayed off since.
After this screen, I usually unplug it. I continued to play around with the reader, which I haven’t really done before.
This is apparently what the State emissions computer sees when it is plugged into your car, as this same information is printed on the paper inspection receipt you get.
Freeze frame data is all the information about what is going on in the vehicle’s monitored systems, when an emissions fault occurs. It is stored when the fault occurs for two consecutive trips. Either it didn’t occur twice here, or, I erased the freeze frame data when I cleared the code.
There’s quite a menu of things you can do and read. This is just one of several screens.
All kinds of information is monitored and stored by the car. It’s amazing to me all these sensors and computers even work reliably after 11 years, given the harsh environment of a motor vehicle.
Even something as simple as the gas gauge is involved!
I guess the “gauge” is really nothing more than an analog readout of the computer data, for us dumb humans.
I have only had 2 instances of the “check engine” light coming on….sort of. After the mileage on my 94 Ranger passed the 100,000 mark, the light would come on very briefly and then go off. I never bothered to have it checked out as I figured the code probably was not being stored and that year of truck has an OBD I type of system so it wasn’t checked during yearly emissions inspections. Either it would pass or not pass.
My Crown Victoria is a 09 and I am trying to take better care of it. So when the “check engine” light came on, and stayed on, I took it to my mechanic at the earliest opportunity. The engine had over 100,000 miles on it, so I had a full tune up done on it.
I guess I should have started my comment by saying this write-up was extremely informative. If an investment of LESS than $100 would save me several times that, I will be heavily inclined to consider this tool.
If you have a Ford I highly recommend getting an OBDLink dongle, I use the MX which is bluetooth and will access all the communication buses on modern Fords. There is also a wifi unit too. The App that comes with the device will work on all cars, but what you want to get in addition is FORScan, both the App for your phone and the windows version to run on a tablet. It will basically do every thing that the factory Ford tool will do. So you can turn off dark mode, ie make the dome light work with the doors and change a number of other settings depending on the vehicle. For example on pickups you can use it to pick between the half a dozen or so different OE tire sizes, just by picking from a list.
As a driver of an Audi B4, I don’t even trust the CEL. It comes on, but goes off every time I tap the brake pedal
My 1990 Honda Civic would have the CEL come on and stay on in very humid conditions (quite common here in South Florida) when the engine was first started. If the car was restarted when warmed up, there was no CEL. I had a mechanic check it – he said it had something to do with an oxygen sensor. I lived with the light for over ten years of daily driving with no apparent ill effect.
I recently bought WIFI OBDII adapter from ebay for less than $20. It is just slightly larger than the OBD plug itself and is powered off of the car itself. You download an OBD app for your phone for ~$2 and then connect your phone to the adapter. You then use your phone to read codes, reset and even monitor engine sensors in real time while driving. Pretty cool technology. I have used it on a Miata, Tacoma and an E46 BMW and it worked great on each one. Interesting to be able to monitor actual engine measurements like temperature and oil pressure that most vehicles don’t offer a gage for anymore.
Call me cheap but the local Auto Zone has a higher quality reader than I have and will read more finite codes and they’ll give a print out to take home, by the way I took my last used car test drive straight to AZ… it passed!!
I’ve had that P0432 code before.
A mechanic friend, who does everything I don’t, recommended replacing the downstream O2 sensor first…just in case. He’d seen the code disappear and besides, chances are if you need to replace the converter, you’ll want to replace at least that oxygen sensor anyway.
When I replaced the cat in my 2011 Equinox, it also took replacing both O2 sensors to get the codes to completely go away. Turns out that after I replaced it, Chevrolet issued a recall. Fortunately I hadn’t yet thrown the old one away, and the dealer cut me a check to honor the recall.
My check engine light came on once. I immediately pulled over and checked the engine. It was still there running. Must have been a defective light.
My paternal grandmother’s second husband (she lost the first to cancer when I was still a kindergarten student) had a late 80s Celebrity V6 that had an intermittent check engine light. It only came on when on the interstate at roughly 65 plus miles per hour, and would go away if you slowed down.
He always said: “How can get out and check the engine when the car is moving?”
If you drive a Skoda, does the Czech Engine light stay on constantly?
Sorry. I’ll see myself out.
Hehhehe! Love it! Of course this is someone whose favorite comic was The Far Side.
Hah! That’s exactly what I did when I first encountered the CEL. Here are some other ways to deal with the CEL: https://youtu.be/1W5PCYFXLJ4
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We have surely come a long way from the days of counting the number and rhythms of sweeps of the needle on the analog meter, a skill I learned in the era of the Ford EEC IV system.
I resolve that 2018 will be the year of diagnosing and clearing the CEL that has been glowing on the Miata since I bought it. I would have gotten on this sooner if the car displayed a single real-world symptom of something being amiss.
A year ago I got my first OBD2 CEL ever, on our ’01 Beetle, and got a code reader, replaced the coolant temp sensor, cleared the CEL and moved on. Six months later we gave the car to our daughter and a few weeks ago it came on again. Autozone got the same coolant sensor code … I guess our “lifetime warranty” Autozone sensor had a pretty short life. But we’re 600 miles apart and I couldn’t find the receipt, so she bought a new sensor and installed it. But the parts stores won’t clear the code, and I didn’t want her to disconnect the battery and risk messing up the radio (yeah, I know there are workarounds). We’re meeting this week for Christmas and I brought my code reader.
BTW, we decided to meet up in Ashland, Oregon, about half-way between our homes, since neither our daughter nor my wife had much time off. Not quite Eugene, but still a CC delight. 30 seconds off the freeway on our arrival and I’ve already seen two Alero’s and a Previa, not much later I’ve seen a third Alero and an original Toyota van.
The CEL on my 2012 Mazda 3 just went on last week accompanied by the TSC light. No codes, took the gas cap off and put it back on, CEL light went off about 40 miles later, passed smog, no lights since. No idea how multiple lights invovled
Call me a luddite, but after dealing with computer controlled stuff for so long, I choose to drive non digital stuff. Beautifully simple and functional. It just works. I cringe whenever I hear stories of friends with mid 2000’s Mopar stuff with failed ecm’s. No factory support and the aftermarket rebuilds are spotty at best. Nothing like being forced to replace an otherwise usable vehicle at considerable expense.
Yes, I have come to appreciate the simplicity of ‘analog‘ system in my 1971 Alfa Romeo, but there were times when I would appreciate the onboard diagnostic system.
My late father‘s Mercedes-Benz was one of the easiest cars to work on thanks to the feature of pressing certain buttons in sequences to call up the error codes and fix them accordingly. When his air conditioning system flaked out on us, it would cost thousands of euros at the official Mercedes-Benz service centre. I was able to fix the issue for less than €20, using the parts from OBI and Conrad Electronics (German equivalent of Home Depot and Fry Electronics) and heaping help of YouTube videos.
My 1986 Chevrolt Celebrity was the hardest because it was often difficult to figure out at a glance or by the seat of pants what went wrong without going on a major expedition in hunting down the gremlins and dealing with them. When the car failed the state emission inspection (almost annually), it meant spending $50-$200 to remedy. Sometimes, I had a nagging feeling that the state inspection was rigged to fail older cars more often: without onboard diagnostic system to refer, I would never know…
The fuel level is a critical emissions control system PID. The Evap monitor won’t run unless the fuel level is in a specified range. It does vary from mfg to mfg but typically it needs to be in the 25-75% range for it to run and complete that test.
Does your unit support Mode$06? If so that is the next step in diagnosing that P0432. You want to monitor the individual cylinder missfire counts for the bank that cat is on. A miss sends a bunch of unconsumed oxygen into the exhaust where it messes with the O2 sensors and can affect just how well the cat can do its job. So if you have a number of misses but that number is below the threshold of setting a specific cyl code or a random miss code that can be the root of the problem.
The algorithm for determining if a specific cyl code does of course vary from mfg to mfg but they all have a count over time component. So a nice long drive is the way to go. You might find a 100 or more counts and no code because enough of them did not occur in that specified rolling time period.
A periodic check will find that coil that is getting iffy well before it turns on the light and hopefully well before it turns to a flashing light.
IMPORTANTLY you don’t want to drive your car if the light is flashing. That means that the problem is more serious and continuing to drive can cause more damage to the engine and/or cat.
Couple months ago the ECL on my 02 Nissan Altima came on and the mechanic told me it was a leaking exhaust. He fixed the problem (flexible joint) for 120 bucks and the the light went off and my car was running a lot more quiet, not too bad I must say.
During a trip to Kenora, suddenly the car was making the kind of noise when you have a blown muffler. I took it back to the shop thinking the repair they had done somehow went bad.
The problem was: one of the O2 sensor popped out of its place and was hanging by its cord. I drove the car like this for over 100 Km and no ECL came on. He check the light and it is OK…
Intriguing, isn’t it?
The cat efficiency check is only run under very specific operating conditions and that is the purpose of the rear O2 sensor. So if you didn’t drive it under the right conditions in that trip then that monitor won’t run and the car won’t care about the rear O2 sensor. There are also what are known as 2 trip monitors, that means the fault has to be detected in 2 consecutive trips before it will turn on the check engine light. Add the two together and yeah you can end up with it not turning on the check engine light, even though it did store a pending code.
I forgot to mention that yes you cleared the freeze frame data when you cleared the codes. I’m surprised that the code reader doesn’t mention that when it confirms that you want to clear the codes.
I sometimes take a cab home from work, and my driver has a late model VW minivan. In fine Volkswagen fashion, every warning light that could possibly be on is lit continuously. Why do people torture themselves with this European junk? Just buy a damn Ford or Chevy and be done with it. I’ve had Volvos, I’ve had Audi’s NEVER AGAIN
If you’re in the US, the only “late-model VW minivan” is the Routan, which is a rebadged Chrysler minivan.
I’d replace “in fine Volkswagen fashion” with “As is traditional with most American cabs,” as in:
As is traditional with most American cabs, every warning light that could possibly be on is lit continuously.
Many years ago I worked on a project gathering in use data for check engine lights. We gathered the data from cab fleets, as they were our happy hunting grounds for check engine lights, regardless of the vehicle manufacturer.
First CEL I ever had was on my beater 97 Civic. Found a mention on the net that pulling a particular fuse would erase the light. Done and done. Light never recurred in the remaining 6 months I had that car.
Next CEL was on my beater 02 Escort. No such luck on finding a magic fuse to pull. Scanner purchased on eBay failed to operate, sent back to seller. Picked up a scanner at Meijer. Code indicated a leaking idle air valve (apparently common on Escorts). Erased code, but it recurred several months later. Replacing the valve is about a $200 proposition, so ran the car for several more years, erasing the code once or twice a year when it tripped. (beats me how Jim could stand staring at that light in his Miata all these years)
One day my aunt called up “the check engine light came on in my Civic”. I said “do not take it to the dealer. I’ll bring my scanner next weekend”. Scanner said front O2 sensor heater failure.. Cleared the code, started the engine and the light immediately came on again. No time to deal with it that day, so I headed home. Few days later, my aunt called “took it to the dealer, they said same thing wrong (as I said), $300 to replace the sensor”. I’m groaning and rolling my eyes. until she said she had not had the work done. I went up to Belletire and got a quote to replace that sensor ($100). Fortunately Belletire has expanded to Kalamazoo, so next time I was over there, took my aunt and the offending Civic to the local store and had the sensor replaced. The CEL did not return. QED.
Driving my beater 06 Focus to the Henry Ford Museum a couple months ago, noticed as I turned into the parking lot that the temp gauge seemed to be reading lower than normal. On the way home, the CEL tripped. Scanner said coolant temp below thermostat temp. Articles on the net indicate thermostat stuck open is a common problem on Duratec engined Foci, and an expensive fix as the thermostat is a bear to get at, $389-$487 according to Repair Pal. Cleared the code and the thermostat decided to start working again as temp indication was back to it’s normal level.
That scanner has gone down in the Book of Steve as a cost effective expenditure.
” Replacing the valve is about a $200 proposition, so ran the car for several more years, erasing the code once or twice a year when it tripped. ”
Cleaning the valve is a $10 proposition and worthwhile because the odds are the problem is solved.
I agree a scanner is an asset to have.
Cleaning the valve is a $10 proposition and worthwhile because the odds are the problem is solved.
It crossed my mind to pull the valve, as it was in plain sight on top of the engine, and hose it down with carb cleaner. It only tripped the light if the car idled longer than a couple minutes when fully warm, so wasn’t worth the bother.
Our ’02 BMW 325it had just finished a basic Oil Stop type oil change. Then the Service Engine Light Soon came on and I just figured it was that Oil Stop didn’t re-set the light. For the heck of it, I asked our local, country mech to check it- after driving for about a month with it illuminated. PHEW! The local mech diagnosed it as a MAJOR brake line failure which was about to cause dire consequences (we live atop a steep hill). I got lucky. Don’t ignore these lights. They might be on for a real reason.
The timing of this post is quite ironic for me – on Dec. 23 I was taking my dad out on a few errands and the Check Engine light on my ’10 Odyssey came on. The van seemed to be running fine, but I pulled into a parking lot and checked the gas cap and made sure I had oil – all fine. We were planning a post-Christmas driving trip so I wanted to get this checked out. After dropping him off at home I went to the local Midas I use (booked solid, closed on 24th) and Honda dealer (booked solid, closed on 24th) and out of desperation went to the local Canadian Tire – my last choice for service due to the mixed quality of service/repairs.
A diagnostic said it as a misfire on my #4 cylinder, requiring a new ignition coil and plugs. By that point it was late in the day and they couldn’t get the coil till the 24th (fortunately it was open yesterday). I got the car back and everything is fine. It sure is dumb luck that it would fail just before Christmas.
You are right that the gauges on modern cars (and not-so modern now) are driven by the computer. My Ford ute is 20 years old and had a ‘diagnostic mode’ that would use the odometer display to show a variety of raw data from the ECU, including fuel usage (it does not have a trip computer), speed without the ‘correction’ applied for the speedometer and actual temperature, oil pressure etc.