All,

Just got back from a nice long cruise in the wagon, and it all went well.

Noticed that I've been getting Code 232 lately at position 2 using the OBD1 code reader in the driver side front fender, though I have no Check Engine Light (CEL).

So can I use the FAQ even though that is for LH 2.4 and mine is LH 3.1?

If so, why do I not get a Check Engine Light (CEL) like the FAQ says I should?

How or what should I further diagnosis to eliminate this code?

The car appears to be running fine, but I'd like to run this to ground if I can.

Any thoughts, and thanks in advance.

Matt

"If so, why do I not get a Check Engine Light (CEL) like the FAQ says I should?"

Maybe you should take your reading of the Frequently Asked Questions with a grain of sodium chloride. Keep in mind FAQ is not FACT, but point out the error to Steve if there is one.

232 is not a CEL-setter. It can be a head-scratcher. I've solved them in many ways, most of them dealing with leaks in the intake or exhaust. My approach is stethoscope, but I'd think smoke would be more effective.

Fuse 6 resets everything instantly. I don't ever bother with the push-button code reset. Clears adaptive trim memory like right now. Takes about 10 miles or so to restore that.
--
Art Benstein near Baltimore

Dear Walter,

I hope you can help me here. The other day, I set off for work leaving my husband in the house watching the TV as usual. I hadn't driven more than a mile down the road when the engine conked out and the car shuddered to a halt. I walked back home to get my husband's help. When I got home I couldn't believe my eyes. He was in our bedroom with the neighbor girl.

I am 32, my husband is 34, and the neighbor girl is 22. We have been married for ten years. When I confronted him, he broke down and admitted that they had been having an affair for the past six months. I told him to stop or I would leave him. He was let go from his job six months ago and he says he has been feeling increasingly depressed and worthless. I love him very much, but ever since I gave him the ultimatum he has become increasingly distant. He won't go to counseling and I'm afraid I can't get through to him anymore. Can you please help?

Sincerely,
Sheila

Dear Sheila:

A car stalling after being driven a short distance can be caused by a variety of faults with the engine. Start by checking that there is no debris in the fuel line. If it is clear, check the vacuum pipes and hoses on the intake manifold and also check all grounding wires. If none of these approaches solves the problem, it could be that the fuel pump itself is faulty, causing low delivery pressure to the carburetor float chamber. I hope this helps.

Walter

From my experience I suggest being very careful with your LH3.1 AMM. A $450+ part new, and hard to find used.

Do not unplug the AMM until the battery neg(-) has been disconnected and no power is in the car's electrical system.

I killed a LH3.1 AMM by cleaning it with AMM spray. A mystery...??

I've never used that stuff... I think they call it MAF sensor cleaner. Sure have read a lot of "used it and the thing was dead" stories, but nothing scientific. Maybe we shouldn't use MAF cleaner on our Bosch AMMs. ;)


--
Art Benstein near Baltimore

I went to a seafood disco last week...and pulled a mussel.

Well that is interesting.

So your saying I couldn't use my limp home mode then if need be?

I'll have to remember that from now on.

Matt

I suggest clearing the code, running the car and double checking the OBD code again, both reset the OBD reader and pop out fuse #6 and reinstall.

Does the code 2-3-2 return?

How old is the O2 sensor? Does it need to be replaced?

Is your CEL light working? Bulb OK?

A code could show if you have an intermittent fault in the wiring or a part is just starting to fail and throwing the code once in awhile.

I run LH3.1 and find most LH2 codes applicable, but there is a separate LH3.1 code diagram in the Bentely manual... Which I don't have handy.

Bert

Bert,

Thanks for your response.

I've cleared the code several times, though I have not popped out fuse #6. What does fuse #6 do?

When I do clear it, it does not return right away, but will eventually.

The O2 sensor is at least 4 years old. It may be older as I have not replaced it since I bought the car in 2013, though this past fall I did replace the Catalytic converter and reused the O2 sensor as they are not cheap! Is there a test I can perform on the O2 sensor to see if it is failing?

The CEL light is working as it comes on every time I go to start up the car.

Thanks in advance,

Matt

Th info in the FAQ you're referencing is meant for Volvo 740 / 940 equipped with LH-Jet 2.4 / EZK116.

https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm

Bosch Motronic 1.8 and newer in the Volvo 960/90 (1996+ 940) and is a single Bosch brand name for a combined fuel control / emissions & ignition control / emissions ECU (or engine control module [ECM]). Some early Motronic versions may have had a fuel ECM and a separate ignition ECM.

LH-3.1 / EZK116 is a 240-only affair. The same EZK116 controller without EGR (apparently the same used with the -561 non-EGR LH-Jetronic 2.4 ECU), AFAIK. Well, certainly EZK116 with no EGR / Pulsair on LH3.1 240 autos. Though you have at least two or three LH-3.1 ECUs beginning with a maroon label 0 280 000-572 ECU in 1989.

That table you see on the page is sort of awful, combing LH-Jet 2.4 (we can imply 3.1) with the listed Motronic 1.8. The two right-most columns in bold are for Motronic 1.8, used on 1992-1995 (1996?) 960.

https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm#LH24FuelInjectionFault

Code 2-3-2 for LH-Jetronic 2.4/3.1 is lean or rich condition in the exhaust at idle, as the oxygen sensor (lambda) encounters it as a comparison to air mass inducted and fuel metered into the engine, and ignition (spark) figures in there someplace. LH-Jetronic / EZK fault tolerance is forgiving before setting an OBD code, certainly when sensors are tired, so, you'd be best to test the AMM / MAF and the Oxygen sensor using a known good multimeter. Not the crappy digital multimeters like I got for 4$ from Harbor Freight.

Also, verify no air intake induction (vacuum) leaks after the air filter and up to the air intake port gasket. And no exhaust leaks before the oxygen sensor.

Oxygen sensor heater works?

And you keep up with the air filter box thermostat replacement, or have blocked off the exhaust heat shield preheat air inlet into your air filter box?

So, the aforementioned imbalance between engine air / fuel induction, proper spark can cause the error code. A small air intake leak can cause this. A larger air intake leak causes the 2-3-1 and 2-2-1 code when driving at speed. Same for exhaust. Or weak spark.

No more codes at all. You repeat the button press to see if it blinks outs any other codes in sockets 2 (fuel) and 6 (ignition)? You sometimes have to repeat it the code check for other codes unless 1-1-1 or the same fault codes display with each code check attempt.

Or low voltages or poor ground connection can cause fuel to air imbalance.

Though Art B. can provide better insight than I can. (My disclaimer.)

Heh, you also live near Baltimore!

Hope that helps.

Wednesday's MacDuff.
--
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KGV,

I've now driven the car over a 1000 miles and have not had the code 2-3-2 re-appear.

The fix (I Believe):

The exhaust pipe out of the cat had come loose to the point that it rattled every time I would start the car up and accelerate.

At first I thought that the CAT was loose, but upon further inspection I found the pipe loose and sliding very freely from the back of the CAT.

I've tightened it up a few weeks ago and since then I've taken several trips of well over a 100 miles at a shot and have had zero recurrence of the code.

The the two good things out of this are:
1. the bothersome noise is now gone, and
2. gas mileage has improved.

Any ways, there you have it for those who are interested.

Matt

Hiya TheBrickTank,

Hope your Burgundy (?) wagon is all fixed up and and in fine fettle. The image you have as your account image.

So, you had an exhaust leak downstream of the catalytic converter? It was leaking at the union? Did the clamp come loose on you? Ooops!

Where the long output pipe that is part of the catalytic converter that secures to the front resonator (muffler) input?

I guess the run would be short enough to allow exhaust gasses to exit rather freely. Reducing back pressure such that the 02 sensor at the front of the catalytic converter would encounter a reduce mass of gas (D'oh!), moving a bit faster, so the engine control system may rate that as an imbalance.

Though I could not guess whether what the 02 sensor would encounter would be too much or too little oxygen (020 in the exhaust). I guess more if your 1991 Volvo 240 fuel economy suffered.

Welp, glad you got it fixed. I'd usually make the presumption, unless mentioned, the exhaust is secure and all union tight. Like that bracket connection hanger at the end of the header pipe. (I tend to major on the minor too much here, perhaps? My myopia.)

Welp, glad it's all fixed!

Happy Volvo-ing 240-ing and such!

Season's Greetings! Happy Holidays!!!!

Thank you,

Duffed and Mac.
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KittyGreyVolvo,

Thanks for the response.

More questions than answers this time around.

Is there a write up on here somewhere about how to test the AMM/MAF and the O2 sensor?

How do I know if the O2 heater is working? What/where can I check?

I can smoke the car to see if I have a air leak on the intake side, though I do not think so at this time. Not sure about the exhaust side, though I did just put a new exhaust header gasket on as I removed the header to fix broken off bolts when I removed the down pipe. I also replaced the cat at the same time all with a new gasket, so I don't think the exhaust is leaking from the header to before the cat. It may be slightly leaky after the cat, but not before.

The air box thermostat may be in there and it will need to be checked, however the pre-heat hose has been off as long as I've owned the car. In fact, it was one of the first things I removed. Now I just need to go and plug up the hole and remove the flapper.

As far as codes are concerned, I only checked #2 and then cleared it. I checked #6 last night and all I got was 1-1-1. Not sure if clearing #2 clears #6, so I may have to wait until it sets again before I can verify no codes on #6.

That's all for now. Now back to getting my "new to me" 1990 on the road worthy.

Later,

Matt

Hi Matt TheBrickTank,

Happy Thursday to you all day long.

On the OBD code check box, when you clear codes, you clear codes for the engine control unit (ECU or engine control module [ECM]) that is connected to the tester probe. So clearing the OBD socket 2 clears fautl codes contained in the LH-Jetronic 3.1 fault code memory space. No effect on the EZK116 control unit module (there are so many phrases you can refer to the computer thingy ...). Though removing the #6 fuse depowers the entire engine control system, and codes clear. I forget how long.

I'll back track just a bit. The socket 2 code 2-3-2 mean an imbalance (fuel, air inducted, proper spark, at idle, v. exhaust gas oxygen content). So the fault code is to a degree.

When you encounter the other two aforementioned socket two fault codes, 2-2-1 & 2-3-1, it is to a degree of severity. Meaning a more severe imbalance as, at cruise, engine consumption and exhaust over comes the minor imbalance. Yet a steady foot to maintain an even speed means less variance between enrichment during acceleration as with getting up to th cruise speed, with more atmosphere and fuel inducted (eaten?) into the engine.

I don't keep notes on testing the mounted and operating AMM other than a back probe of the orange (?) wire to verify proper power to it. Using another combination you can test the output, and I recall it, in one of Art's post, to be rated at millivolts or a voltage below that of B+. Also, I check the potential to ground for the AMM (the black or brown wire). You can test the outputs (green / yellow & red / white striped wires), yet I dunno where to find such info for the LH-Jetronic 3.1 AMM. I've looked, inspite of four model years equipped with LH-Jet 3.1 89-93. Somewhere are articles here on your brickboard.com/RWD/ that may contain values of an AMM at rest (dash lights are on yet engine OFF, ambient temp is 60-75 F°) B+ power is nearly the same or same as B+ battery post, and potential to ground is good. I don't know how to test the the green / yellow & red / white striped wires to know a good AMM at rest. I can test my LH-3.1 AMM / MAF, yet want to duplicate how Art does it with the five wire LH-2.4 AMM / MAF.

I'll see what I can find. It would also be swell to have a half dozen or so 3.l LH-Jet MAFs / AMMs as I do for the two LH-2.4 equipped 240 I have. And all AMMs are good.

The oxygen sensor is easy to test. Disconnect the single wire protected in the rubber boot. Start the engine. Proper oxygen sensor heater function quickly heats the oxygen sensor. Your multimeter, set to no less than, say, 2 volts, or if DMM, scales to the voltage input, should display a wildly varying range of DC volts between .1 and .9 Volts DC. As an oxygen sensor begins to fail, the responsive slows and the voltage range narrows. I forget what a failed oxygen sensor display on a connected multimeter.

When I get one of these cars, the most recent in August 2007, I run my fingers along the power and engine control wire harness. Loosening and securing grounds, disconnecting and reconnecting each connector. Applying some DeoxIT (when I had some) to the connector. making certain the connector does not lose the little silicon seal that can sometimes fall out (like the AMM / MAF connector, or a fuel injector connector [yet found each, again, later, or had a spare]), and the power stage connector (up there, next to the battery, encountering the ambient environment no matter how nasty, like the ->1990 25 AMP engine control ATC fuse, and the B+ junction block on the inner fender behind the battery) that I dunno what corrosion does to give it the corrosion gremlins.

How many miles? Yet it idles smoothly?

Is this your maroon or Burgundy 1991 wagon you have the image of with the front end collision damage? (Very sorry that happened.)

You replaced the exhaust manifold output to header pipe output? Some detergent water (enough dish detergent to make bubbles) in a spray bottle on the exhaust manifold gaskets at the head, again at the flange where you replaced the gasket, and again at the header pipe output to catalytic converter input (the triangle or spin gasket) can reveal exhaust leaks. Soak the unions, have a remote start or assistant start the engine, soak the unions and see if anything bubble. Any warmth in the head and exhaust pipe prevent bubble formation, though you may have to really soak it.

As for the intake, with all the turbulence of the water pump fan, using smoke stick seemed sort of futile. Though many other here have found intake leaks when visual inspection, and an inspection of vacuum lines, the air intake between the air filter box out (how's that preheat flappy valve, new thermostat or cold air inlet only or?) to the throttle body in?

Injector seals where the o-ring seals seals against the injector end and the bore for them at the end or the air intake port. Some would use carb cleaner, a little bit, in the recess, on a cold engine, to see if the carb cleaner gets consumed and effects the engine idle. Though a smoke stick would work, I guess? Though I've not encounter failure of these on LH-jet equipped, just on K-jet.

The EVAP piping from the cannister under the fender in front of the left front wheel all snug and secure (I had to replace the cannister to air intake vapor hose on my 1991, and clean the EVAP valve atop the 1990 cannister).

I've also found holes in the accordion hose between the AMM / MAF and the throttle body. Degrease the thing inside and hot in hot water, though don't flex it too much. Scour with scrubby nylon pad around the holes. Final wipe with isopropyl rubbing alcohol, dry, and (I use) Goop UV resist adhesive sealant like the RV you find in Walmart between the auto and camping sections in two-four thin coats to seal the holes.

I've also found my job at aligning and re-clamping the air induction piping between the air filter box to the throttle body poor. You have to be careful, yet let the years or the natural placement be your guide. Please try to avoid anything in any way touch the accordion hose. I also add soft adhesive padding on the inner fender where the accordion hose may contact the inner fender should engine vibration get it to make contact.

I use sunlight or strong over head light while looking inside and turning the accordion hose, or a bright flash light inside the accordion hose in a darkened room, to look for holes there. Gently turn and flex the hose to expose it to light so you can see where the light / air leaks through if so.

Also, I've jarred the brake master cylinder vacuum with the valve so it was not seated.

You then have a the small host of vacuum lines and their terminations. At nearly each end of a vacuum line, I use a UV-resist black plastic zip tie strap to snug it up at the end. One the ends of the vapor lines, at the end of the set of large vapor lines forming the stack of PCV piping that sets atop the PCV oil separator breather box and poke out between intake port runner #3 & #4. Then, again where the hose secures to the top of that PCV flame trap and flame arrestor sieve assembly and the end of the accordion hose where it secure to the flame trap.

Though a test of PCV "breathing" and seal is where you are sure of a seal between the PCV connection at the accordion hose, with the small vacuum line, secured to the flame arrestor sieve housing, to the air intake port between #2 and #3 runner, removed from the port and pinch closed, is to disconnect the PCV pipe from the accordion hose and blow through the hose (yes, is nasty) with oil fill cap off. Should be easy to exhale forcefully, with some resistance, yet displace air should come out through the fill cap. Restore and secure the oil fill cap. Blow again. Should about impossible to blow through it. Though listen for leaks. Though if the o-ring beneath the PCV oil separator breather box has lost seal, you'd see oil stain around the PCV oil separator breather box on the engine block surface around and below it.

One last check is the air intake port to cylinder head gasket securing hardware. Whether factory original or replaced, the gasket compliance can mean the securing hardware stack compression is lost, and may form vacuum leak. For a lark, on my 1970s 240s, all with k-jet, I'd check the intake port manifold securing hardware. I found, with hex socket at the end, on a stack of extensions, I always could loosen one to three of the nuts. I'd then tighten them to torque using a 3/8" dial in torque wrench. Though very old gaskets by years and high miles can crush or crack with little effort. I'd been lucky to date. The overhead cam air intake securing nuts, all eight of them, are easy to get to with 13 (12?) mm socket at the end of a long extension. My mechanic's touch has sort of failed me with 3/8" craftsman ratchet (and the made in China ratchets hive a different feel). Yet tight to snug, and a little bit more, if loose.

Sorry to go on so. I wish I could say this or that, yet I treat thing thing preventively all at once when I get it. Yet in order for your socket #2 code 2-3-2:
- Vacuum / air intake leaks.
- Exhaust leaks. (You can leak exhaust slightly yet won't hear it)
- Disconnect battery and unseat, reseat engine control wire harness connections. DeoxIT is extra insurance, the spray or the salve grease. Loosen & tighten grounds (though ground ending in ring terms that secure the fuel rail to the air intake port - a Volvo TSB with them ring term crimps, more urgent if your engine bay shows corrosion on surfaces, the power stage ground, and so forth, though them Volvo wiring diagram show you a ground, yet not where) in the engine bay and under the dash. Both ECUs have a black wire that secure to a self tapping metal screw. (The boxes are Faraday cages, yeah? So the PC boards inside do or do not ground through the ECU metal box? I forget.)
- Test the 02 sensor, yet at four years since you replaced it (how many miles), it probably works okay or better. I'll see if I can find values for testing the LH-3.1 AMM /MAF. (Just be sure the preheat flappy valve in your air filter box works or is not stuck to hot air only and let the cold air in, only. You choice for the $$ you spend.)

Sorry to go on so. I wish I could point to a single cause. Though some length here, doing these checks take very little time, if you have the time to do it.

Questions?

Hope that helps you.

Happy Thursday, all day long.

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