93 Dodge Caravan Stalling Problems

I bet both computers (assuming that he gets the original back) work fine. The prior code - 77 - was read wrong, so it could have been part of the following code meaning the following code was bogus also. It could be that instead of a 77 and 53 that there's actually 3 separate codes in there.

The sad thing is that the original poster could probably have gone to one of many auto parts places (Autozone, etc.) and they would have a scanner behind the counter that they could have plugged into the vehicle and told him the exact codes.

Ted

I can't say that for sure. I'm saying that an unknown used computer is more likely to have trouble than a known computer that you had been using every day. Personally, I prefer the devil I know over the one that I don't.

Yes, I doubt your computer was ever the problem. It was trying to tell you the problem and you instead swapped it out.

Matt

I haven't checked my service manual lately. Does it identify which codes cause MIL illumination and which don't? I don't remember seeing that in the list when I've visited it in the past.

Matt

And the sad part is that it usually isn't the computer per se that is the problem, it is the I/O section. In my past life designing and installation industrial control systems, the I/O gear failed at least 10 times as often as the CPU, memory or other parts of the control computer. Good thing for us that the I/O was part of a subsystem and we could replace individual I/O cards. The integrated units in cars don't allow that flexibility as near as I can tell ... I've never tried to open one up. In my case, I'm about 80% sure that the failure is just the one I/O point that switches the rear washer pump to ground. The pump stays on constantly. I unplugged the connector from the computer and could short the appropriate pin with a paper clip and control the pump just fine, so it appears that pin is being held to ground constantly.

Given the interface between the AC control module and the BCM, there is come chance that the BCM is being constantly commanded to provide rear wash, but I think that is less likely than a shorted output on the BCM, however, it appears from the manual that the interface between these two modules is a bus, not discrete wires and I have no means to monitor the bus to read the commands being sent. However, I unplugged the module in the dash that contains the rear washer switch and the BCM still kept pin held to ground.

Matt

Isn't the output circuit integral with the computer?

Matt

Yes, it is. Read the whole post. In order.

That's part cost only. Replaced it myself.

I did. Your post wasn't clear that you understood that these were not separate components. You discussed computer in one paragraph and "output circuit" in another and though they were separate items.

Matt

Yes. Both my '87 and my '95 manuals say which does what.

Thanks for everybody's help. To sum things up: I should assume that the computer was not the problem?

The real problem is that the EGR Valve Assembly should be replaced?

Am I correct in this assumption.

I am going to have the thing looked at again tomorrow, and will post the results tomorrow night.

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Yeah, I was at CTC playing games with computer to find correct parts for my 1987 2.2L 'van, parts (some of them are there). For example coolant sensor (round 3 pin style), wasn't listed for 1987, had to try eariler years 86, 85 bingo, ditto to early distributor (1985 again), I guess chrysler was trying to clean out all the remaining stocks on the production floor. So on.

My 'van was a change-over year in engines, computer, emissions & fuel system.

BTW, get your 'puter back. In meantime, try the codes again and watch the light carefully. Blinks starts right away when finished toggling that key.

Computer ever rarely fail. Smack the young guy, this guy needs to do a troubleshooting steps carefully, with experience will only take moments. Buy your own real service manual not hayes or chiltons! The real thing will pay off in no time. These books has excellent diagnostic throubleshooting charts, texts. Ebay or dealer's. It is 3 book set, sometimes four.

Always get the real service manuals for vehicles first thing if you like to maintain them and here is good too.

Cheers,

Wizard

Assume nothing, please. Do the trouble shooting yourself with basic info you learned to confirm which is the faulty part and use their suggestions or find another decent mechanic and throubleshoot.

Cheers,

Wizard

It is *likely* the original computer was fine. The replacement computer is faulty.

That may be, but it is by no means clear. What is needed is proper

DS

It is "Computer memory power lost within last engine start events" *WHEN READ WITH A DRB OR OTHER DIAGNOSTIC COMPUTER*.

When it is read via the flash code method:

If any fault codes are stored, the flash sequence *will* start with 12.

If no fault codes are stored *and* the SMEC/SBEC has lost power feed within the last 50 to 70 (per spec) engine start events, the flash sequence *will* be "12, 55".

If no fault codes are stored *and* the SMEC/SBEC has *not* lost power feed within the last 50 to 70 (per spec) engine start events, the flash sequence *may* (per spec) consist only of "55".

See above.

That is not accurate thinking on your part.

DS

Well, I take it back -- just tried it by disconnecting the intake air temp sensor, and got a 12, 23, 55. But where is this documented? There may well be an EGR fault, but if the module reporting faults is

Documented? Dunno.

It's one of the things covered in Chrysler factory technician training.

I am bringing the van into another mechanic Thursday moring. Will give the final verdict then, hopefully! Funny but the van has run better the past few days as the weather has warmed up, but the popping or sputtering sound, and hesitation, are still there.

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DID YOU EVEN TRY TO DICONNECT THE VACUUM LINE TO THE EGR TO SEE IF THE ENGINE RAN SMOOTH.

Warren