On my wife's 1995 960 sedan, I am getting the following error codes, and check engine light is on. I am having trouble understanding which "table" to use when I searched online for meaning of the codes - i found something but it differentiates "LH-Jetronic 2.4+", Regina and EZK 116 no idea what that means...

There are two diagnostic connector units, labeled A and B. For unit A am getting code 221 on socket 2 and for unit B code 122 also on socket 2.

Note that the reference guide I used notes that on box A I should also read codes on socket 6 - but that socket is empty on the car. I do have a socket 6 on box B but no codes stored (am getting response 1-1-1).

SHe did have recently an issue where the car died while getting to a red light, but restarted fine. Mechanic could not find anything and ended up replacing fuel trap. Have switched to premium fuel since and no more incident like that in the last 2 weeks. THought I mention as perhaps this issue is related/unresolved now that the CES light came on.

Any help is appreciated. I have a feeling it may be either related to Mass Air Flow Sensor or Oxygen Sensor. THe former I think I could replace (or perhaps first clean) myself, seems easy to access. THe latter I am unsure whether that is a DIY or not.

 

Here is something I found on another site, brickboard.com.
It may seem you have a vacuum leak or a bad intake manifold gasket.

I would also check, clean and tighten all under hood electrical connectors, Volvo connectors are weather resistant at best, the can will corrode.

DanR '94 964 356,000 miles (122,000 on the new engine)


General Notes on On-Board Diagnostics in Volvo RWD Cars. Volvo started using self-diagnostics on its Bosch LH 2.4 engine management systems in 1988 on 700 series non-turbo cars and in Regina-equipped cars. Earlier Bosch LH 2.2 and Turbo cars until 1990 had very limited self-diagnostic capability using an LED tester. In LH 2.4 cars, If a system fault occurs, then the "check engine" lamp will illuminate, signifying the presence of a fault code. For every model year using LH2.4 up to and including the '95s (except 200 series DLs and GLs), you can flash out fault codes, as well as perform input and output testing, through the OBD-I diagnostic connector unit simply by inserting a little self-contained probe and pressing a button. You do not need a special scan tool to read codes. As electronic systems were added to more Volvo models, more socket options and even more diagnostic connectors were added.
Unfortunately, you cannot use a generic code reader on any of these OBD-I cars: you have to manually extract the codes from the systems as noted below. 1996+ cars have the entirely different OBD-II system which requires a computerized code scanner to read codes through a special data link.

The diagnostic connector units for OBD-I systems are small black rectangular boxes mounted in front of the left-side(driver-side in LHD countries) shock tower. Earlier cars have only one unit ("A"); later cars have two ("A" and "B"). Diagnostic connector "A" contains the test terminal probe (the wire mounted on the side of the box in the picture) used in both A and B along with the test button and the LED readout lamp. In diagnostic connector A, socket 1 is for the electronic transmission (if your 960 or 90-series car has the AW30/40), socket 2 for fuel injection or Motronic, socket 3 for ABS, socket 6 for ignition and socket 7 for the instrument cluster. If the 1992+ car is so equipped with connector B, socket 1 is for the climate control, socket 2 for cruise control, socket 5 for the SRS and socket 6 for the memory seats.
For later 1996+ OBD-II equipped cars, the diagnostic connector was changed to an electronic data link and moved from under the hood to in front of the shifter in the console. As a result, you need a computerized scan tool to do everything from checking for codes to resetting the maintenance light. Maintenance light resetting, by the way, was returned to a push-button method in the very late '90s.
Note that 200 series DLs and GLs have self-diagnostic capability only for fuel and ignition control. All other systems except 1990-93 SRS require a proprietary tool. For '90 to '93 models with air bags, just jump a terminal to ground to get codes out of the system.
Can't Obtain an OBD Code? Malfunctioning OBD Code Reader?
[Inquiry] I tried obtaining a fuel injection diagnostic code and can't even get 1-1-1.
[Response: Chris Herbst] I have run into a LOT of Volvo products with bad diagnostic readout units, usually caused by corrosion. While it is possible that there is no signal TO the diagnostic unit, it is just as likely that either the connection in the terminal, or the connection TO the unit from the ECU computer, is bad. You should try cleaning those connections, and if necessary you can jiggle the connections until you DO get proper readings. I've never had it where I wasn't able to at least read codes and reset the computer, although sometimes it was when I was squeezing the connections into the diagnostic readout unit, or jiggling them around. While your problem could be the ECU, more likely it is corrosion or a bad connection, especially if the engine is operable. [Chris Mullet] When I could not get the LED to illuminate, it turned out that the LED itself was burned out. I picked up another one off a wrecked car and it got me back into business.
If you have an ohm meter to test continuity, you can pop the unit open and check out the LED, resistor, button contact, etc. Be careful as there are a couple tiny springs that can go flying when you open it up. [Doug Bennett] Remove the unit from the fender wall. The there is a plastic cover that covers the button. There are two small tabs, facing inward. Depress these with a small screwdriver, and carefully swivel the plastic cover away. The button will now come out. BE CAREFUL NOT TO LOSE/DROP THE TWO SMALL SPRINGS ON EACH LEG OF THE BUTTON! Luckily, I had a magnet handy. On both the bottom of the button and down in the test unit itself, are the contacts. Mine were filthy. 15 seconds with a Dremel, reassemble, and all is well!
Does the OBD Code Pinpoint All Problems? [Editor] Absolutely not: the earlier OBD-I systems are quite crude and provide a hint only. Coolant temperature and knock sensors, for example, can fail without any OBD codes being set and the only real test is further diagnostics.

 

221 is- Heated Oxygen Sensor(Rich mixture/part throttle).
122 is- Air temp sensor signal.
I would suggest the MAF sensor is sending a bad signal and causing the o2 sensor reading to be off. First step would be to thoroughly clean the MAF with MAF sensor cleaner, also clean the terminals on the connector plugs.
Ignore the o2 sensor, it is merely reporting a fault in fuelling.

ALL the Bosch EFI systems are developments of the previous systems and are all very close in design and operation to those before them. So the codes generally apply all the way through on an EFI family. IE, codes from digital L jet are fundamentally the same as codes from Regina. And fixing them is fundamentally the same process.

 

thanks for the feedback. Typhoon confirmed what I thought I should do first, clean the MAF sensor. Hope it helps...

 

Update: Cleaned the MAF sensor and cleared the codes.

Also, what I noticed is that the air hose that the MAF connects to is cracked (on the end that connects I believe some ventilation system) That connector was completely off and when I tried to reconnect noticed that the rubber underneath the clamp was broken (not sure if it even requires a clamp, seems like prior mechanic tried to fix that way). I reconnected provisionally and ordered a new part PN 9142004 and will install once received. Perhaps this is what actually caused the error code, but cleaning never hurts and it got me look more closely....

Have driven car for a few days and CEL still off, so seems to have worked! THANKS AGAIN for the help!

Matt