Volvo 850 Supplement Manual page 23

connector. Disconnect passenger compartment temperature sensor
connector. Connect jumper wire between temperature sensor connector
terminals No. 2 and 4.
3) Connect an ohmmeter between test unit pins No. 6 and 45
(driver's side), and between test unit pins No. 6 and 46 (passenger's
side). If ohmmeter indicates continuity, wiring is okay but intake fan
may have an open circuit. Go to next step. If ohmmeter indicates no
continuity, intake fan is okay but wiring has an open circuit. Repair
wiring as necessary.
4) Ensure ignition is off. Ensure connector from passenger
compartment temperature sensor is disconnected. Connect an ohmmeter
between temperature sensor terminals No. 2 and 4. See Fig. 6. Ohmmeter
should indicate 50,000 ohms. If ohmmeter indicates no continuity,
intake fan has an open circuit. Replace passenger compartment
temperature sensor.
DTC 4-1-4 & 4-1-7 DRIVER'S OR PASSENGER'S SIDE TEMP.
SENSOR INTAKE FAN SEIZED
Turn ignition off. Uncover passenger compartment temperature
sensor. Check if fan turns freely by hand. If fan does not turn
freely, replace fan. Check fan for anything that could cause blockage
and clear as necessary. If fan is okay, replace passenger compartment
temperature sensor.
DTC 4-1-8 NO CONTROL SIGNAL TO ECC POWER STAGE
1) Ensure ignition is off. Connect test unit to ECC control
module. Check ground circuits. See DTC 1-2-1, OUTSIDE TEMP. SENSOR
CIRCUIT SHORTED TO GROUND. If ground circuits are okay, go to next
step.
2) Turn ignition on. Place fan control lever to maximum
speed. Connect voltmeter between test unit pins No. 6 and 42. If 6-8
volts are present, go to next step. If voltmeter indicates zero volts,
wiring is shorted to ground. If voltmeter indicates 12 volts, wiring
is shorted to voltage. Repair wiring as necessary.
3) Ensure ignition is off. Disconnect power stage 4-pin
connector. See Figs. 14 and 15. Connect an ohmmeter between test unit
pin No. 42 and power stage connector terminal 1A. Ohmmeter should
indicate continuity. If no continuity is present, check wiring for an
open circuit.
Fig. 14: Identifying Power Stage Connector Terminals
Courtesy of Volvo Cars of North America.