Erasing Codes - Volvo 850 Supplement Manual

(10 seconds on, 10 seconds off), switch A/C compressor on and off, and
turn control panel A/C indicator on and off. If A/C relay does not
respond as indicated, check A/C relay. See A/C RELAY CHECK under
TESTING.
Self-Adjustment Of Damper Motor Limit Positions
1) Turn ignition on. Place fan (blower motor) lever in manual
mode. Turn function selector to AUT (automatic). Ensure system is in
TEST MODE 4.
2) Enter control code 9-9-9 by pressing button on diagnostic
unit 9 times in quick succession. Enter each of the 9 series 3 times,
with a short pause in-between to allow LED to come on again. ECC
control module is now ready to adjust damper motor limit positions
automatically.
3) Wait about 10 seconds for fan to start. Turn ignition off
to exit TEST MODE 4. Turn ignition on. AC OFF and REC indicator on A/C
control panel should flash. Drive car for a few minutes at speeds
greater than 20 MPH.
4) Stop car and turn engine off, but leave ignition on for at
least 2 minutes to enable ECC control module to store all values.
Start TEST MODE 1 and record DTCs. If DTC 1-1-1 appears, self-
adjustment is complete. If DTC 5-1-1 appears, self-adjustment is not
complete.
Changing Data Transmission Speed/Rate From ECC Control Module
To On-Board Diagnostic Unit
Enter desired control code (3-1-1 or 3-1-2) by pressing
button on diagnostic unit "A", with a short pause in-between to allow
LED to come on again. System always starts at normal speed unless
another option is selected. If another option was selected, system
will revert to normal speed each time ignition is turned off.

ERASING CODES

1) All codes must be displayed at least once before they can
be erased. To erase codes, ensure selector cable is connected to
terminal No. 1 of diagnostic unit "B". See Fig. 2. Press and hold
diagnostic button for at least 5 seconds. LED should illuminate 3
seconds after button is released.
2) Press and hold diagnostic button for a minimum of 5
seconds more. When button is released, LED should go out. Ensure codes
have been erased by pressing diagnostic button once. If display shows
1-1-1, codes have been erased/cleared. If a DTC will not erase/clear,
perform that particular code's diagnosis again.
DTC 1-2-1 OUTSIDE TEMP. SENSOR CIRCUIT SHORTED TO GROUND
1) Turn ignition off. Install Test Unit (981 3190) and
Adapter (981 3194) between ECC control module and harness connector.
See Fig. 3. Using ohmmeter, connect test leads between ground and test
unit pins No. 6, 9, 10 and 56. Ohmmeter should read zero ohms in each
terminal. If resistance is as specified, go to next step. If
resistance is not as specified, check for open circuit.
2) Disconnect Adapter (981 3194) from ECC control module.
Disconnect outside temperature sensor (located on right rear of engine
compartment). See Figs. 4 and 5. Connect ohmmeter leads between test
unit pins No. 10 and 14. Ohmmeter should read infinity. If reading is
as specified, go to next step. If reading is not as specified, check
for shorted circuit between sensor harness connector and ECC control
module.
3) Connect ohmmeter leads between outside temperature sensor
terminals. Resistance should be 8000-12,000 ohms. If resistance is not
as specified, replace outside temperature sensor. Clear and recheck