Volvo 850. Instruction - page 62
Fig. 9: Identifying Duct Temperature Sensor Terminals
Courtesy of Volvo Cars of North America.
DTC 1-3-2 & 1-3-4 DRIVER’S OR PASSENGER’S SIDE DUCT
TEMP. SENSOR CIRCUIT OPEN OR SHORTED TO POWER
1) If DTC 1-3-2 and 1-3-4 are both present, check for open
circuit in duct temperature sensor common ground (Brown wire). If DTC
1-3-2 and 1-3-4 are not both present, there is an open or short
circuit in wiring between ECC control module and duct temperature
sensor. Go to next step.
2) Ensure ignition is off. Connect test unit between ECC
control module and A/C system connector. Check ground circuit and
repair as necessary. See DTC 1-2-1, OUTSIDE TEMP. SENSOR CIRCUIT
SHORTED TO GROUND. If ground circuits are okay, go to next step.
3) Turn ignition on. Check driver’s side duct temperature
sensor wiring by checking voltage between test unit pins No. 56 and
47. Check passenger’s side duct temperature sensor wiring by checking
voltage between test unit pins No. 56 and 48. Voltage will vary with
duct temperature, but generally should be in 0-3 volt range.
4) If voltmeter indicates 5 volts, check duct temperature
sensor wiring for an open circuit. Go to next step. If voltmeter
indicates 12 volts, check wiring for short to voltage between
connector terminal No. 2 (Green or Yellow wire) and ECC control module
terminal C1 (driver’s side) or C2 (passenger’s side). See Figs. 8 and
10.
5) Ensure ignition is off. Disconnect ECC control module, but
leave test unit connected to control module connector. Disconnect
connector from each duct temperature sensor. Connect jumper wire
between duct temperature sensor connector terminals.
6) Check driver’s side duct temperature sensor wiring by
measuring resistance between test unit pins No. 56 and 47. Check
passenger’s side duct temperature sensor wiring by measuring
resistance between test unit pins No. 56 and 48.
7) If continuity is present, wiring is okay but duct
temperature sensor has an open circuit. Replace duct temperature
sensor. If continuity is not present, duct temperature sensor is okay
but an open circuit is present in wiring. Repair wiring for an open
circuit.
Fig. 10: Identifying ECC Control Module Terminals
Courtesy of Volvo Cars of North America.
DTC 1-3-5 NO ENGINE TEMPERATURE FREQUENCY SIGNAL
1) Run engine and check whether temperature gauge in
instrument cluster works. If temperature gauge works, engine
temperature signal is reaching instrument panel, but Green/Gray wire
between ECC control module terminal A23 and instrument cluster has an
open circuit. See Fig. 10.
2) If temperature gauge does not work, temperature sensor
wiring may be shorted or engine temperature signal may be absent from
engine management system.
3) To check wiring, turn ignition off. Check Green/Gray wire
between ECC control module terminal A23 and instrument cluster for a
short to ground or voltage. If no fault is found, problem may be in
engine management system. See the G - TESTS W/CODES article in the
ENGINE PERFORMANCE section.
DTC 1-4-1 & 1-4-3 DRIVER’S OR PASSENGER’S SIDE TEMP.
SWITCH FAULTY CONTROL SIGNAL
These codes may be caused by an internal fault in ECC control
module, temperature switch, or internal wiring. Erase DTCs. Turn
ignition off, then on. Test ECC system. See TEST MODE 1 through 4
under TROUBLE SHOOTING. Check if DTCs return. If DTCs return, replace
ECC control module. Perform self-adjustment of damper motor limit
positions under TEST MODE 4.
DTC 1-4-5 AIR DISTRIBUTION SWITCH FAULTY CONTROL SIGNAL
Code may be caused by an internal fault in ECC control
module, air distribution switch, or internal wiring. Erase DTCs. Turn
ignition off, then on. Test ECC system. See TEST MODE 1 through 4
under TROUBLE SHOOTING. Check if DTCs return. If DTCs return, replace
ECC control module. Perform self-adjustment of damper motor limit
positions under TEST MODE 4.
DTC 1-5-1 & 1-5-2 FAN SPEED SENSOR CONTROL SIGNAL MISSING,
SIGNAL TOO HIGH OR SIGNAL SHORTED TO GROUND
Codes may be caused by an internal fault in ECC control
module, fan speed switch, or internal wiring. Erase DTCs. Turn
ignition off, then on. Test ECC system. See TEST MODE 1 through 4
under TROUBLE SHOOTING. Check if DTCs return. If DTCs return, replace
ECC control module. Perform self-adjustment of damper motor limit
positions under TEST MODE 4.
DTC 2-1-1, 2-2-1, 2-3-1, 2-3-3 & 2-3-5 DRIVER’S OR
PASSENGER’S SIDE DAMPER MOTOR POSITION SENSOR CIRCUIT
OPEN OR SHORTED TO POWER
1) Check if DTCs 1-2-2, 1-2-4, 1-2-6, 2-1-1, 2-2-1, 2-3-1, 2-
3-3 and2-3-5 are present. If all DTCs are not present, there is an
open or short circuit in a wire between ECC control unit and damper
motor which applies to DTC. See AUTOMATIC A/C-HEATER SYSTEM DIAGNOSTIC
TROUBLE CODES table, then go to next step. If all DTCs are present, an
open circuit is present in common ground at ECC terminals A9 and A10.
See Fig. 10.
2) Ensure ignition is off. Connect test unit between ECC
control unit and control unit connector. Check ECC grounds. See DTC 1-
2-1, OUTSIDE TEMP. SENSOR CIRCUIT SHORTED TO GROUND. Also check power
supply to damper motor position sensor. See TEST MODE 2 under TROUBLE
SHOOTING. If ECC grounds and power supply to damper motor position
sensor are okay, go to next step.
3) Turn ignition on. Connect voltmeter between test unit pins
No. 10 and No. 17 (driver’s side damper motor), No. 18 (passenger’s
side damper motor), No. 20 (ventilation damper motor), No. 19
(floor/defrost damper motor), or No. 21 (recirculation damper motor).
4) If voltmeter indicates 12 volts, check wiring and ECC
control unit terminals for a short to voltage. See PIN VOLTAGE TESTS
under TESTING. If voltmeter indicates 5 volts, an open circuit is
present in wire. Go to next step.
5) Ensure ignition is off. Disconnect ECC control module, but
leave test unit connected to ECC connector. Disconnect 6-pin damper
motor connector and install a jumper wire between connector terminals
No. 1 and 2. See Figs. 11-13. Connect an ohmmeter between test unit
pins No. 10 and 8. If ohmmeter indicates continuity, go to next step.
If ohmmeter indicates no continuity, check for open circuit in Brown
ground wire.
6) Connect jumper wire between damper motor connector
terminals No. 2 and 3. Connect ohmmeter between test unit pins to test
respective damper motor. See DAMPER MOTOR TEST UNIT PIN NUMBERS
(RESISTANCE CHECK) table.
DAMPER MOTOR TEST UNIT PIN NUMBERS (RESISTANCE CHECK)
Pin No. Damper Motor
8 & 17 ..................................... Driver’s Side
8 & 18 .................................. Passenger’s Side
8 & 20 ....................................... Ventilation
8 & 19 ..................................... Floor/Defrost
8 & 21 ..................................... Recirculation
7) If ohmmeter indicates continuity, wiring to damper motor
terminal No. 3 is okay, but an open circuit is present in damper motor
position sensor. Go to next step. If ohmmeter indicates no continuity,
damper motor position sensor is okay, but open circuit is present in
wire between damper motor connector terminal No. 3 and ECC control
module connector "A".
8) Ensure ignition is off. Disconnect damper motor connector.
Connect ohmmeter between terminals No. 1 and 3. See Fig. 11. Turn
damper motor output shaft. Ohmmeter should vary between 0-12,000 ohms.
If resistance is to specification, go to next step. If resistance is
not to specification, there is an open circuit in damper motor
position sensor.
9) Connect ohmmeter between damper motor terminals No. 2 and
3. Turn damper motor output shaft. Ohmmeter should vary between 0-12,
000 ohms. See Fig. 11. If ohmmeter indicates no continuity, there is
an open circuit in damper motor position sensor. Replace damper motor.
Fig. 11: Identifying Damper Motor Connector & Component Terminals
Courtesy of Volvo Cars of North America.
