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I have a 1995 model 960. The engine light comes due to a failure in the Engine Control Module. This does not effect the car performance or running, just everytime I have to take the car to the service to get it off... The service claims ECM needs to be replaced but they also state that many people use their 960s w/o changing the ECM. Any opinion? The module costs around $1.000. Should I have it replaced or continue? Anyone having the same problem?
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You can sometimes find these ECM's on eBay.
What code(s) are you getting? As stated by someone else, you can pull them yourself very easily.
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1998 S90 062,700 1995 964 142,100
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That light almost surely does not indicate a fault in your ECM but rather indicates an engine fault elswhere that the ECM is detecting. It could be something simple and most likely is. It sounds as if the ECM is doing exactly what it is supposed to. Did the tech read and record the stored fault code or just do reset? If he did not read the code and discuss with you what it meant then find a new tech fast.
I am sure some techs would love to sell you a new ECM and at the same time fix some simple problem. He then has a spare ECM. I know this happens.
Auto Zone will read the OBDII code at no charge.
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David Hunter
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we looked on the code in the PC... everytime it is the same (I do not recall the coding)...
on the manual, let's say in the computer, it is written that the ECM needs to be replaced... but by the same time the tech says no problem you can continue like this as many people do...
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Why don't you state the code? If you do not know, you can pull it. Is there really a code that says replace the ECU? Not sure if your car has the LH2.4 system diagnostics or the newer OBDII system. Either way it is important to know the code and either way the code is easily obtained. Sorry to seem a bit anal about this but I do not think you want to install a new computer without being sure, they do not often fail you know.
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David Hunter
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A couple things. Your 1995 960 does not require a computer to read the codes. Nor does it need a computer to clear the codes. Their is a little light and test wire under the hood to read and reset the codes. Check the FAQs.
Do you have any drivability problems? Low mileage? You may be able to drive your car with a failing ECM but, you fuel use, emissions and performance will not be optimized.
You can purchase a new ECM from a volvo junkyard for about $500. Again check the FAQs for parts sources. I use a dismantler in Sacremento, CA. Phone no. 916 635-9970.
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thanks for your interest. I had no idea if I could retrieve the codes by myself, I will try. by the way, I called the tech and asked what was the last code we read and he replied 5-1-1. I looked at the table FAQ but could not find the code, the codes stop at 4-x-x. I think something is wrong or I am in the wrong direction. The car is Swiss made. Do you have any idea about this code... thanks in advance...
Kemal
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The 700/900 FAQ section basically just has the OBD-I codes for late 80's/ early 90's cars. You can find the additional OBD-II Volvo codes here
You'll see that a Volvo OBD-II code of 5-1-1 means there is some kind of failure in the "Adaptive oxygen sensor control, provides leaner mixture at idle".
That sounds to me like the ECU is attempting to lean out the mix at idle, but the feedback from the O2 sensor does not indicate that a leaner mix was achieved. This does not sound fatal, but means your fuel consumption may be higher during engine idling. Apart from fuel consumption, the only other aspect I can think of might be failing a vehicle emissions test especially if that test happens to measure emissions output at idle (many only measure under load at higher revs).
I'm not sure what exact component might be causing this problem, but if anything I would be suspicious of the O2 sensor itself, possibly not burning deposits off adequately. Deposits on the O2 sensor itself may be a problem leading to slow reponse and an incorrect reading. Now if your mechanic is intimately familiar with this problem and says otherwise then maybe the ECU, otherwise I'd just take it as an educated guess. In any case, a new O2 sensor is a heck of a lot cheaper if you're going to throw parts at the problem. Is there any evidence that an aftermarket O2 sensor has been installed? Personally, I would doubt the ECU is at fault unless there is a poor contact at the main ECU connector or at the O2 sensor connector. If there is corrosion or a connector has been previously opened for some reason then that might be a possibility, otherwise wiring and contacts probably aren't an issue.
Here's some other things I'd want to consider. Engine deposits are both a major source and a significant indicator of marginal running problems and that would mean incomplete combustion and that would mean a perpetually high O2 sensor reading. There are many factors that might contribute to that. I can easily imagine an ECU attempting to fine tune the mix to the lean side in a dirty engine having problems. City driven cars are especially prone to engine deposits. What grade and quality of fuel are you using? Try at least a 92 octane [(R+M)/2 rating]. Try switching to another quality brand (additives do vary). Give your engine a long highway run at higher revs to help burn off accumulated deposits. How good are your spark plugs? Worn, fouled or incorrectly gapped plugs lead to incomplete combustion. How clean is your throttle body? A dirty throttle body (always important to check and clean) might inhibit idle air flow or be an indication of other problems. Could a stuck EGR valve be involved? Could an injector be leaking? Could the AMM be involved? Even something simple like has the air filter been changed in living memory? Then there's always the Swiss factor. Any chocolate stuck on the O2 sensor?
Hope that helps. Others may have a more definitive answer.
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There are only OBD-I codes for 200/700/900's, only the 850's got OBD-II. Change all OBD-II references to OBD-I [stupid system won't let me edit my own post]. The 700/900 FAQ primarily covers diagnostic codes for the LH 2.4 system. Other systems and later LH systems will have additional codes.
From what I can tell from AllData, the proper Volvo description is
5-1-1 "Idle Long Term Fuel Trim Lower Limit". The statement "Adaptive oxygen sensor control, provides leaner mixture at idle" more or less says the same thing, but fails to indicate it's a long term (as opposed to momentary) problem.
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-Dave (not to be confused with a real expert, just goofing around at this)
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Odd. I thought all 96+ model year cars were required to have OBD-II?
Did the later 960s/90 series stick with OBD-I even tho the Motronic system got an upgrade?
- alex
'85 244 Turbo
'84 245 Turbo
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You may be quite right about OBD-II in '96. The ad hoc information sources I was using for 960's could easily have extrapolated '94 and '95 information into '96.
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-Dave (not to be confused with a real expert, just goofing around at this)
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My Chiltons book lists the codes a bit differently than the last posters site.
Code: 5-1-1 Long-term idle air trim, idle
Code: 5-1-2 Short-term fuel trim.
The previous posters codes were listed as OBD II codes. A 1995 960 is not OBD II.
As far as the cause of code 5-1-1, it could be your idle air motor as mentioned in the code. However, it also could be a leaky intake manifold gasket. In order to check the intake manifold gasket, spray carb cleaner around the gasket with the engine idling. If the engine stumbles you have a leak.
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thanks for the explanations dave... I think I will have an hot conversation this weekend with the tech...
but I do not understand what u mean by main ECU connector... you mean that the ECU might be opened before and not fixed as it should be...
kemal
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Sorry, I forgot to answer your last question. When I mentioned the main ECU connector I was just referring to the massive plug on the ECU box (there is only one). If that connector has been subject to excessive moisture then there could conceivably be a little corrosion especially if the original connection has been disturbed. A bigger concern if that connector has been off and re-installed is the possibility of wire damage, pin damage or pin fatigue, either due to forcing a misaligned connector or probing with a test lead from the front rather than the side. Hopefully your friendly mechanic would never cause such things nor open the ECU box just for a peek or worse to poke around (have to admit I have).
And try not to get hot under the collar with your mechanic unless your BS meter hits the upper stop. One incident can ruin a relationship with an otherwise good mechanic.
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-Dave (not to be confused with a real expert, just goofing around at this)
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Please note Win960's (Shawn?) reply.
First off, he's quite right, only the FWD Volvo's had OBD-II. The B6304F's used in the 960's had the Bosch Motronic system and in 1995 I believe it was the M1.8 system which was OBD-I. The fact there are codes beyond what's shown in the FAQ would be due to newer engine management systems and EPA requirements. I've edited my post accordingly.
The 5-1-1 code description he found in Chilton does indeed seem a bit different from what I saw. I'm curious, so I did a bit more digging, including the 5-1-2 code for comparison.
What he found in Chilton:
Code: 5-1-1 Long-term idle air trim, idle
Code: 5-1-2 Short-term fuel trim
[although Chilton usually shows codes specific to a fuel system, they have been known to use their own interpretation of other Volvo specs for things like torque and clearances, so I don't consider them gospel]
What I originally found on the referenced ECU web-site, a generic list for Volvo's up to 1997 from a commercial ECU site:
Code: 5-1-1 Adaptive oxygen sensor control, provides leaner mixture at idle
Code: 5-1-2 Oxygen intergrator at maximum lean running limit
What I found on the web for Motronic M4.3, an OBD-II system used in 1995 Volvo 850's and which appears to be direct from Bosch:
Code: 5-1-1 Long term fuel mixture too rich at idle
Code: 5-1-2 Short term fuel mixture too rich
What I found from AllData for Motronic M1.8, an OBD-I system used with the B6304F in the Volvo 960's (including 1995, I believe) and which appears to be a photocopy of the Volvo literature:
Code: 5-1-1 Idle Long Term Fuel Trim Lower Limit
Code: 5-1-2 Short Term Fuel Trim Lower Limit
Now near as I can tell, for the 5-1-2 code (that you don't have) the descriptions are consistent (although it's interesting to note how they say it). For your 5-1-1 code, I think the last three are all in agreement, you're running too rich at idle. A stuck IAC valve or air leak (unmeasured intake) shouldn't affect any of this. So I'll still stand by my earlier comments and my opinion of Chiltons.
-Dave (not to be confused with a real expert, just goofing around at this)
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I knew that as soon as I mentioned Chilton no one would let my post lie. Just to clarify, the title of the fault code chart in chiltons says; "1992-95 960 Series with Bosch Motronic 1.8 Trouble Codes." The book does not list any other possible ignition system for the 960 series cars for the 1992-95 model years.
One other note. Recently Token Ring Man discussed his frustration at finding the solution to a P0172 trouble code. In the end he concluded that it was an intake manifold gasket leak. The description for code P0172 in Chilton's is "Long-term fuel trim, part load Long-term fuel trim, idling."
One last thing, I was wondering how Dave thought my name was Shawn, then I remembered about my email address. My name is Winston. My email address is winshawn@aol.com. The Shawn is my wife.
People seem to get sensitive on these forums. I am not trying to pick any fights. Just putting information out there to help everyone fix their cars.
I too am no expert.
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Yes, many people (most people?) won't let any references to the Chilton or Haynes manuals die. They tend to be fairly incomplete and inaccurate for the Volvos at least.
If you're at all interested in the codes, I highly recommend you find a Volvo sanctioned list of codes. I suspect that the Motronic Fault tracing, Repair, and Maintenance manual from Volvo would have such codes (TP2305201), if that didn't perhaps the Volvo Scan Tool Fault tracing, Repair, and Maintenance manual would (TP2310201). These manuals are available at www.volvotechinfo.com for about $35 each. At the very least you may want to contact volvo and see what they say as far as a list of codes.
- alex
'85 244 Turbo
'84 245 Turbo
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Hi Winston. Yes, I got a little curious about your win960 handle (sounded like some Microsoft module) and even more curious when I saw Shawn (normally a female, but sometimes a male spelling) in your e-mail addy. Anyway, I really appreciate your information and input. There's no argument going on, just a conversation. What got me started on this thread was the mechanic's suggestion to replace an otherwise working ECU without a good explanation. As for Chilton's, there's absolutely nothing to be ashamed of as there's precious little in the way of DIY manuals for the later RWD cars. My Volvo library includes Chilton's and I often have to use it for my 940's. :)
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-Dave (not to be confused with a real expert, just goofing around at this)
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I have a list of codes from the Chilton manual that lists those 5-x-x codes. I do not have it with me today but maybe this evening I will post them. The list of codes in the FAQs is not complete. I have a feeling that some people will tell me that the Chilton manual sucks, etc. I know. I know. Anyway, I will try and post the codes this evening.
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Do you think he gave you the wrong code? Why not ask him what that code means and what source he used.
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David Hunter
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