Bren,
On the 232 code look for a vacuum line leak or leak in the intake area, spray a little WD40 or something around suspect areas and see if the idle changes. If not then look at the Mass Air Flow sensor in the filtered air inlet tube, use a multimeter to check the voltage there.

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) or MasterTech / Tech2 scantool, 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.

For the 4-1-4 code:

Code 4-1-4 (Charge Pressure Control)
1) Turn ignition on. Leave MAF sensor connected. Connect
voltmeter between MAF sensor connector terminals No. 2 and 4. If
voltmeter reads .1-.2 volt, go to step 3). If voltmeter does not read
.1-.2 volt, go to next step.

2) Turn ignition off. Ensure MAF sensor and ECM connector
terminals are clean and tight. Repair as necessary. Reconnect
connectors. Turn ignition on. Connect voltmeter between MAF sensor
connector terminals No. 2 and 4. If voltmeter reads .1-.2 volt, source
of code was poor contact in MAF or ECM connector terminals. If
voltmeter does not read .1-.2 volt, retest using new MAF sensor.

3) Turn ignition off. Connect breakout box and check grounds.
See COMPUTERIZED ENGINE CONTROLS in I - SYSTEM/COMPONENT TESTS
article. Disconnect ECM. Turn ignition on. Connect voltmeter between
breakout box pin No. 42 and ground. If battery voltage is present, go
to next step. If battery voltage is not present, check wiring between
ECM terminal B42 and Transmission Control Module (TCM) terminal B1 for
an intermittent fault.

4) Turn ignition off. Check Turbocharger (TC) control valve
and ECM connector for contact resistance or poor contact. Repair as
necessary. Reconnect TC control valve and ECM connectors. Turn
ignition on. Using Volvo scan tool in Diagnostic Test Mode (DTM) No.
3, check that TC control valve ticks. If TC control valve ticks, go to
next step. If TC control valve does not tick, retest using new TC
control valve.

5) Turn ignition off. Check hoses between TC and TC control
valve, and hose between TC control valve and pressure servo for
wastegate valve for obstruction or kinks. Also check that TC control
valve is not blocked between Red and Yellow connectors when valve is
activated. Valve should be open between Red and Yellow connectors when
not activated. If hoses and TC control valve are okay, go to next
step. If hoses and/or TC control valve are blocked, repair as
necessary.

6) Turn ignition off. Remove hose from pressure servo.
Connect Manometer (999-5230) and Pressure Tester (998-5496) to
pressure servo. Pump up pressure to about 46.6 psi. If pressure servo
fully opens, check pressure servo setting. See procedures in the
I - SYSTEM/COMPONENT TESTS article. Replace wastegate valve pressure
servo. If pressure servo is not okay, retest with a new pressure
servo. Replace wastegate valve pressure servo.


So it looks like either a bad vacuum line or the mass air flow sensor could be your culprit. I don't know what the whirring noise is you hear after resetting.

Let me know if you need more from the shop manual, but unless you have a great workshop garage you'll probably end up taking it to a Euro repair shop that has the MasterTech or Tech2 analyzer. Good luck.


Mike
'95 850T