850 1997 ecu re- programming required?

[mercuric]

Yes, the ECUs are some tough cookies.. I find it amazing they last decades under the hood, even with that ventilated box.. Ever pull one out after heat-soaking in the engine bay ~30 minutes after shutting down the engine? You can't even hold that puppy!

Check for fuel pressure at the rail, spark at the coil while cranking, and positive voltage to one side of the injectors with key on (the last verifies main relay operation, which in turn verifies a bunch of other stuff).

In terms of which ECU to use... There is a Bosch part number, 0 261 20x xxx that is important, but is not all-telling. 0261 203 072, for example, the 850 T5 ECU, came in multiple flavors. EGR, SAS, automatic/manual, and immobilizer/non-immo are the main differences. There should be a sticker with 4 numbers/barcodes on it. There should be a P0xxxxxxx number, like P0915576, etc.. Uusally the upper left of the barcode/number combinations. That's the software variant, and that's what you want to match up to be sure it's going to work.

Other ECUs with the same Bosch (026120xxxx) number will likely start the car, but may be set up for different features -- For example, a -072 ECU out of a 95, which had SAS/EGR, will throw codes for those components as they didn't come on 97 cars, although the car will start and drive.

[senior]

history: drove to store one morning,was in for 2 hrs approx:, came out to a no start situation. never had any problems before other than an abs module had to be replaced a year ago.the ECU made no change in status of car. I replaced crank sensor and still no start.I will re post the exact results of my tests asap but for now I have 12 volts on red lead of coil with key on,voltage on green wires at injector plugs w/key on.no spark at plugs or at distributor coil cable. with a noid light installed on #1 injector I get a flash at first part of cranking but nothing after until I let off the key and crank it over again. one flash only. honestly don't think that the cam pos. sensor has been checked .

[abscate]

There was another thread where this was diagnosed as interfering signals on the CPS, recently

[senior]

well as promised this is what we got so far. battery voltage while cranking,11.41 long crank too.compression: lowest 175, highest 180. no spark at plugs or coil. voltage present on green injector wires w/key on. 12 plus volts on red wire at coil w/key on.but no signal from test light on blue wire at coil when cranking over. coil power stage 0 ohms @ #1 terminal,#3 term. key on has 12.68 volts, #4 term. while cranking .21 but not for sure the test was done correctly. conducting tests solo. camshaft positioning sensor ,three wires not marked, so right to left or l to r ? #1 o ohms, #2 5.03 while cranking, and #3 think I screwed that up as well ( 11.43 ) w/key on. one code found: P0120 TPS/PEDAL POSITION SENSOR A CIRCUIT MALFUNCTION. I do smell fuel/alcohol odor from exhaust after cranking over. don't have exact fuel psi pressure but I do have pressure at rail. two of three, comp., fuel, but no spark. I'am known as the guy that will die trying because if it takes until the tires fall off it will start and run again. my wife said it ran when we got out of it. bless her heart. we thank you all very much

[17yearsofboost]

I am having the identical issue on my 94 850 turbo. I got the same TPS code which is weird because it only happened after plugging in the ICM with the key on. But a bad TPS shouldn't matter, I drove with a bad 1 for years.

[senior]

I worked on it last night hoping to make some progress but all i got was worn out. I checked ecu pin position A21 to cam positioning sensor #2 on the connector using an ideal multi-meter with a continuity setting , when I put the probes to those two places it made the alarm or whatever kind of sound it makes. so with that being said does that mean it is ok or not?. nothing was hooked to either end of that wire unless there's a branching point of that particular wire inside the housing that the wires go through. if that test result is a good one then maybe the cps is faulty.

[17yearsofboost]

the beep sound from your Ohm tester means the wire is closed or good. no sound would mean open or bad. Did you check continuity on the crank sensor? Should be right next to cam sensor clip. You should get <500/>300 ohms.
Replacing my CamPos sensor fixed mine. She started first crank. The ECM needs the reference from the cam & crank to tell the coil to fire.
It is weird that it throws a TPS code and no Cam code during this no spark condition though.

[senior]

I changed the crank sensor already because it wasn't testing out . I've done many test's on this thing and even tested the test's that I find myself retesting tested test's. you know what I mean. thanks for the input and I'll post the good news soon as I get it.

[senior]

OH HAPPY DAYS, cam sensor installed and 2nd time I turned it over I was smiling ear to ear. thank's every one here for being here. where else can one find a forum that compares to you guy's ?? the repair manual that talk's to you step by step. good luck to all