Hello Bricksters,

After fixing a vacuum leak last week, I drove the 94 850 to work today, and now the Check Engine light is on again. It is giving me a 232 and a 121 again. Last week was the same thing, and I found that a rubber elbow was broken on a vacuum line which I fixed, and put in a new vacuum line. The car seems to be running okay, but the light has come after i reset it twice today already. Have any of you seen this instance where you had a 121 and 232 at the same time. What am I dealing with here? In the meanwhile, I feel the gas mileage is not optimal either. Any suggestions? help!

Az.

94 850 124,000 miles

Well you need to make sure you have fixed all the rubber elbows. If this is not a turbo, there is a rubber elbow over by the flame trap housing that often also needs replacing. For the 122 maf code try re-seating the connector several times. Also once all the elbows are repaired, disconnect the battery for at least 10 minutes so the adaptives can re-set themselves.
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Rich K. http://www.volvospeed.com/bay13.htm bay13@cox.net

Its kind of long winded but here goes: I think both are related to the air intake system. Check for cracks or leaks in the intake inlet between the MAF and Throttle Body. Good luck.

Mike


Code 1-2-1 (MAF Signal)

1) If signal from MAF sensor is less than .2 volt or greater
than 2.2 volts at idle, or is considered incorrect according to RPM
and throttle angle, this is interpreted by ECM as a fault and code 1-
2-1 is set. If fault is permanent and signal is too low, go to step
8). If fault is permanent and signal is too high, go to step 3). If
fault is intermittent, go to next step.

2) If fault is intermittent and signal is too high, check all
wiring and connectors for loose contacts and open circuits. Also check
wiring between MAF sensor connector terminal No. 4 and ECM connector
terminal A4 for an intermittent short to voltage. If fault is
intermittent and signal is low, ensure all fresh air hoses, and upper
and lower charge air cooler pipes are correctly attached. Check wiring
between main relay connector terminal No. 3 and MAF sensor connector
terminal No. 3 for an intermittent open circuit. Also check wiring
between MAF sensor connector terminal No. 4 and ECM connector terminal
A4 for an intermittent open or short circuit to ground.

3) Turn ignition off. Wait about 90 seconds and disconnect
MAF sensor. Connect ohmmeter between MAF sensor connector terminal No.
1 and ground. If ohmmeter indicates about zero ohms, go to next step.
If ohmmeter does not indicate about zero ohms, check wiring between
MAF sensor connector terminal No. 1 and ECM terminal A3 for an open
circuit.

4) Ensure ignition is off and MAF sensor is disconnected.
Connect ohmmeter between MAF sensor connector terminal No. 2 and
ground. If ohmmeter indicates about zero ohms, go to step 6). If
ohmmeter does not indicate about zero ohms, go to next step.

5) Ensure ignition is off and MAF sensor is disconnected.
Ensure ECM connector terminals are not oxidized and make good contact.
Reconnect ECM. Connect ohmmeter between MAF sensor connector terminal
No. 2 and ground. If ohmmeter indicates about zero ohms, go to next
step. If ohmmeter does not indicate about zero ohms, check wiring
between MAF sensor connector terminal No. 2 and ECM terminal A5 for an
open circuit.

6) Ensure ignition is on and MAF sensor is disconnected.
Connect voltmeter between MAF sensor connector terminal No. 4 and
ground. If voltmeter indicates 0-1 volt, go to next step. If voltmeter
does not indicate 0-1 volt, check wiring between MAF sensor connector
terminal No. 4 and ECM connector terminal A4 for a short to voltage.
If voltage reading is still incorrect after repair, or short to
voltage is not found, replace MAF sensor.

7) Turn ignition off and reconnect MAF sensor. Turn ignition
on. Connect voltmeter between MAF sensor connector terminals No. 2 and
4. If voltmeter indicates about .1-.2 volt, code is setting because of
poor contact in MAF sensor connector and/or ECM connector. If
voltmeter does not indicate about .1-.2 volt, replace MAF sensor.

8) Ensure ignition is off. Ensure fresh air hoses and upper
and lower charge air pipes are undamaged and securely connected. If
hoses and pipes are okay, disconnect MAF sensor. Turn ignition on.
Connect voltmeter between MAF sensor connector terminal No. 3 and
ground. If battery voltage is present, go to next step. If battery
voltage is not present, check wiring between MAF sensor connector
terminal No. 3 and main relay connector terminal No. 3 for an open
circuit.

9) Ensure ignition is off. Wait 90 seconds, then disconnect
MAF sensor. Connect ohmmeter between MAF sensor connector terminal No.
4 and ground. If ohmmeter indicates 9000-11,000 ohms, go to next step.
If ohmmeter shows about zero ohms, check wiring between MAF sensor
connector terminal No. 4 and ECM connector terminal A4 for a short to
ground. If ohmmeter shows infinite resistance, check wiring between
MAF sensor connector terminal No. 4 and ECM connector terminal A4 for
an open circuit.

10) Turn ignition off. Reconnect MAF sensor connector. Turn
ignition on. Connect voltmeter between MAF sensor connector terminals
No. 4 and 2. If voltmeter shows .1-.2 volt, check for poor contact in
MAF sensor connector and/or ECM connector. If voltmeter does not show
.1-.2 volt, test system using a known good MAF sensor.
NOTE: Before beginning testing procedure, disconnect engine
cooling fan relay connector "A". Code 5-1-4 (engine cooling
fan half speed) signal will be set. After testing, reattach
connector.


Code 2-3-2 (Long Term Fuel Trim Idling)

1) Check for other codes. If Code 3-1-5 is stored, perform
testing on that code first. If Code 3-1-5 is not stored, go to next
step.

2) Check status message on Volvo Scan Tool (998-8686). If
status message reads LOWER LIMIT, go to step 8). If status message
reads UPPER LIMIT, go to next step.

3) Turn ignition on. Connect voltmeter between MAF sensor
connector terminals No. 2 and 4. If voltmeter reads .1-.2 volt, go to
next step. If voltmeter does not read .1-.2 volt, test using new MAF
sensor.

4) Check for air leakage in intake system. Repair as
necessary. If air leakage in intake system is not present, go to next
step.

5) Check for air leakage in exhaust system. If there is no
air leakage, go to next step. If there is air leakage, repair as
necessary.

6) Check fuel and residual pressure. If fuel and residual
pressure are okay, go to next step. If fuel and residual pressure are
not okay, repair as necessary.

7) Connect breakout box to ECM and check ground connections.
See COMPUTERIZED ENGINE CONTROLS in I - SYSTEM/COMPONENT TESTS
article. Reconnect ECM. Repair as necessary.

8) If status message reads LOWER LIMIT, turn ignition on.
Connect voltmeter between MAF sensor connectors terminals No. 2 and 4.
If voltmeter reads .1-.2 volt, go to next step. If voltmeter does not
read .1-.2 volt, test using new MAF sensor.

9) Check for air leakage in intake and exhaust system. Repair
as necessary. Check fuel and residual pressure. Repair as necessary.
If no air leakage and fuel and residual pressure are okay, go to next
step.

10) Remove hose leading to intake manifold from EVAP valve.
Connect vacuum pump to EVAP valve coupling. If vacuum gauge does not
show stable vacuum, repair as necessary. If vacuum gauge does show
stable vacuum, go to next step. Check engine oil and fill as
necessary.

11) Start engine and run at idle a few minutes. Using Volvo
Scan Tool (998-8686), read off value on SHORT TERM FUEL TRIM and note
value. Disconnect and plug crankcase ventilation. Read off value of
short term fuel trim once again. If value is more or less unchanged,
go to next step. If value rises, engine oil is diluted with fuel.
Repair as necessary.

12) Connect breakout box to ECM connector and check grounds.
Connect ECM. Check all signals to and from ECM. Repair as necessary.