Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Motronic ECMs: Common Failures?

Status
Not open for further replies.

multiLayer

New Member
Greetings.

I have a Motronic 1.8 module (OBD-I) with a 1-1-2 failure (cannot be cleared -- even with a battery disconnect). Spark, FI, etc. all up; vehicle drivable with some roughness recently setting in.

Not being the average "grease monkey" type, and, having some "real" electronics experience, I would like to simply affect any repairs which might typically be indicated.

However, before digging the module out of the car, I wanted to know what I might be up against. Specifically, it seems as though there are many outlets offering "remanufactured" Motronic 1.8 modules at the usual scalper's rates; so, I'm betting there are a few simple, common failures which take these units out of service from time-to-time.

Any ideas? Would the usual dried cap, SJ, and/or interconnect refit generally address Motronic issues of this ilk? As long as it's not a deliberately malicious codeblock, most common rework would be well within my grasp...

Thanks so much --
 
Hi Multilayer

Welcome to ETO .. .

I presume the vehicle is a Volvo ? .. .. .

Why are you convinced the module has failed ? The 1-1-2 failure code is a fuel injection problem which your given your evidence about 'drivable with some roughness recently' would support that.

The error code would not necessarily be cleared by battery disconnect - especially if the error is still present - they normally have to be reset manually with an OBD scanner or will reset themselves after the self check process if the error is no longer present, ie problem been fixed.

I would have a close look at the fuel injectors and also (if there is one ) the fuel rail pressure control valve .. .. before working on the module.

I had a lengthy, expensive and fruitless experience with such an article a few years ago and the problem turned out to be a sensor costing only a few pounds

S
 
@ Musicmanager:

Thank you for weighing in.

Actually, the code thrown is "Fuel Injection Module Fault". The ECM itself is the only active component (module) in this chain, bearing all apparent FI control on-board. Hence the concern...

I understand about the potential for a wild goose chase: Indeed, one can't even rule out programmatic EOL "enhancement" by the OEM to ensure future revenue! You also do bring up some quite valid points about peripheral issues; but the timing of this run problem is just too close. Again, 1-1-2 is evidently related to an internal module fault condition. The code did initially clear following the manufacturer's procedure, but has now reasserted; and will not clear by any common approach. The diagnostic protocol is OBD-I.

I'll be doing some additional checks along the way to be sure; but the controller seems to have passed a unique internal error code which continuously manifests/reemerges without live interaction (engine off condition). My OP was just to see if there are inherent "weak spots" in this maker's controller systems which might hint towards this particular failure issue.

Thanks again --
 
Hi Multilayer

OK, I could be completely wrong, however please bear in mind a couple of thoughts .. .. .

OBD-I terminology was always a little vague and the expression 'Fuel Injection Module' may indeed include the injection system

I've seen the inside of one of these modules - I hope you've got a good pair of tweezers :)

S
 
Welcome to ETO, MultiLayer!

Did you check to see if other codes were also being thrown? The old OBD1 Motronic (and others) ECUs would not allow code erasures until ALL codes had been displayed at least once.

Any 20+ yo car can develop simple connection problems all over the place.

(Don't do this without first disconnecting the neg. battery terminal.) What my old Volvos (240s, 245s, diesels - irrelevant in this case) seemed to like (I'm in a salt water mist everywhere zone) was periodically having the main (actually only) Motronic connector "exercised", i.e., disconnected and reconnected a few times to clear corrosion, dirt, whatever from the contacts and re-establish good connections. Spraying a little contact cleaner around didn't hurt, either.

Have you checked your fuel gallery pressure? Also, maybe exercise the injector connectors as well.
 
Thank you, folks, for the input here. Sorry to have been away so long, but "Life Happens" ;)

@ Musicmanager:
Good to hear you were able to wrap this type of issue up with a relatively simple plug-in. If you are disposed, what was the nature of your particular failure?

@ cowboybob:
I suspect interconnects could be operative at some level here, too. I'll be trying the simple "pull and wiggle" presently; and, if that affords no ground, I'll dig in behind the module shell and see what might be lurking in those parts (board interconnects, maybe?). Can't hurt in any event.

Ran a vacuum test on the engine, and all is strikingly sound. No reciprocating mechanicals seem to be behind the issue. Fuel supply apparatus/ignition testing will be in the queue.

OT but relevant nonetheless, does anyone have a favorite (non-US) source for Volvo parts? Been having quite an unpleasant time locating NOS for this car on American soil; and would be most enriched by a fuller resource call upon...

Thanks again so much, and have a great weekend!
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top