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Unable to Reset Diagnostic Codes 850 1993

posted by Thumbs on Tue Apr 25 14:14 CST 2017
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last visit: Sat Oct 11 12:06 CST 2014

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Hello again lads,

This time I'm in a jam. I've been trying to fix this stalling/clunky running engine for a while. I've been all over the net looking for resolutions, and found a lot of guys buying parts only to discover they haven't repaired anything at all. I want to be sure of things to the extent I can before investing in repairs.

One bit of new information I want to pass along... Occasionally, the engine bucks real hard, almost like a brief stomp on the brakes... usually during acceleration after the engine has warmed up. The amber CEL flashes momentarily during this engine bucking. I can still smell the exhaust, like the motor is running too rich. I swapped out an extra MAF sensor I had with no change in performance. I used up a lot of MAF Sensor Cleaner on both of them...

Today I decided get the diagnostic codes, reset them and start over with my troubleshooting. I got some strange numbers I've never seen before. Socket B-6 yields no flashes at all. After reviewing all the codes twice, I could not get them to clear. I held the button down for 8-10 seconds and there was no response. I removed the negative battery terminal for 15 minutes, ran through the codes and was still unable to clear the them.

I was able to clear the codes about ten days ago after getting a CEL while doing some testing on the MAF sensor.

Now it seems to be hung up. Here are the codes I can't clear:

A-Module
1 1-1-1
2 1-1-1
3 1-1-1
6 2-1-4
7 1-1-1

B-Module
1 3-2-5
4-1-4
4-1-7
2 1-2-2
5 2-3-2
2-1-2
6 No response

Help!

Thanks in advance,

- thumbs

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Unable to Reset Diagnostic Codes 850 1993

posted by KlausC on Thu Apr 27 10:19 CST 2017
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last visit: Fri Oct 24 10:15 CST 2014

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A6 2-1-4 is RPM speed sensor sporadic

Probably a loose wire or bad connection.

Your SRS light is on. The wiring to the steering wheel air bag is faulty. And the seat belt tensioner on the driver's side is faulty.

The blinking lights on your ECC are because the cabin sensors (both of them) are clogged with dust; and the recirc damper needs to be run a few times manually to speed up the flapper.

The B2 1-2-2 can never be cleared. That is the cruise control module and the code means nothing.

When the CEL flashes, that usually means multiple misfires! and could be related the to the speed sensor.
--
Keeping it running is better than buying new

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Unable to Reset Diagnostic Codes 850 1993

posted by Thumbs on Mon May 1 17:42 CST 2017
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last visit: Sat Oct 11 12:06 CST 2014

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I've been consulting my Haynes Manual. It lists fault codes for "Fenix 5.2 system," "Motronic 4.3 system," and "LH3.2-Jetronic system." Now what chart should I be referring to?

I was finally able to clear the codes in the A module. The A-6 2-1-4 reappeared so I cleaned up the connector which had that green build-up on the contacts.

I do not have an SRS light on as you suggested. I can live with the environmental snags, but the sudden stalling and engine "bucking" I want to solve. Do you think I should be concerned about the fuel pressure regulator? When I disconnect the vacuum line, there's no effect on the engine performance. No fuel in the vacuum line. BTW, that engine "bucking" usually happens when accelerating and in third gear. The other stalling scenario is when I'm stopped, I barely touch the gas pedal and she conks out.

Thanks for helping out.

- thumbs

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Unable to Reset Diagnostic Codes 850 1993

posted by KlausC on Mon May 8 19:51 CST 2017
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last visit: Fri Oct 24 10:15 CST 2014

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A failed fuel pressure regulator will cause hard cold starts and fouled spark plugs due to excessive fuel pressure.

The A6 2-1-4 code means that the computer doesn't know how fast you are going and won't know how much fuel you need to use.

The bucking could be due to dirty or badly work spark plugs. You have an EGR system which might not be closing completely due to dirt. Have you checked the rotor and cap?
--
Keeping it running is better than buying new

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Unable to Reset Diagnostic Codes 850 1993

posted by Thumbs on Mon May 8 22:27 CST 2017
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last visit: Sat Oct 11 12:06 CST 2014

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Klaus,

Again, I am profoundly thankful for your tireless concern...

I think I finally figured this out. After weeks of reading old posts from a variety of sources, I stumbled into a brief discussion where a person recalled reading a TSB, or Technical Service Bulletin regarding a 1993 Volvo 850. It seems that when the 850 engine was designed, the coil wire to the distributor passed too close to RPM sensor wiring. As a matter of fact, a while back I replaced the distributor cap, rotor and wires and probably messed things up.

At the time, I didn't pay any attention to the routing of the coil wire. Apparently my coil wire ended up too close to the RPM Sensor connector and started arcing across. Hence, the intermittent RPM sensor signal, and that horrific bucking I described.

As a test I used a piece of rope to maneuver the coil wire further away from the RPM Sensor connector. I haven't had a buck or misfire in days. Upon examination, I could see an area on the coil wire that had evidence of the spark escaping to ground.

If more 850 owners were aware of this TSB, they might save themselves money and a few headaches.

I'm still a little concerned about my mileage, but my big problem appears to be solved.

You're in more discussions than me, so maybe pass this info along.

Thanks again!

- thumbs

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Coil wire touching RPM sensor wire 850 1993

posted by KlausC on Tue May 9 09:14 CST 2017
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last visit: Fri Oct 24 10:15 CST 2014

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That takes me back. Yes, I knew about the TSB and have mentioned it before. It is a possible problem from 1993-1998 engines, and very difficult to diagnose. I am glad you found it!

Poor gas mileage could be an O2 sensor? They do get old and slow to respond, but not bad enough to trigger a code.
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Keeping it running is better than buying new

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Unable to Reset Diagnostic Codes 850 1993

posted by B.B. on Wed Apr 26 22:30 CST 2017
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last visit: Mon Oct 6 13:15 CST 2014

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You might have a toasted CPU.

You can try this at your own risk:
Try removing the Positive terminal for ten minutes then short that cable end to
to the Neg cable and or ground for a minute to insure that the microprocessors
are discharged. You might get lucky

WARNING Don't take a CPU connector off with the battery connected!

If above doesn't work try disconnecting the battery and reseat the CPU
connectors. Use a light spray of silicone on the pins when off.

The OBD is run directly from the CPU's. I had to reseat the ABS CPU connector
to resolve an OBD failure. The connecter went on tough until a little silicone
spray solved that issue.

Good luck, Bill

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