Volvo 850. Instruction - page 61

DTC 1-2-2 OUTSIDE TEMP. SENSOR CIRCUIT OPEN OR SHORTED TO

POWER

1) Ensure DTCs 1-2-2, 1-2-4, 1-2-6, 2-1-1, 2-2-1, 2-3-1, 2-3-

3 or 2-3-5 are not present at the same time. If any of these codes are

present at the same time, check for an open circuit in the common

ground wire. If only DTC 1-2-2 is present, go to next step.

2) Turn ignition off. Install test unit and adapter between

ECC control module and harness connector. 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.

3) Turn ignition on. Connect voltmeter between test unit pins

No. 10 and 14. Check voltage to outside temperature sensor. Voltage

should be about 2.6 volts at 68

F (20

C). If voltage reading is 5

volts, check for open in circuit or in outside temperature sensor. If

voltage reading is 12 volts, check for open in circuit between sensor

harness terminal No. 1 and ECC control module.

4) Turn ignition off. Disconnect Adapter (981 3194) from ECC

control module. Disconnect outside temperature sensor connector

(located on right rear of engine compartment). See Figs. 4 and 5.

Install jumper wire between sensor harness terminals. Connect ohmmeter

between test unit pins No. 10 and 14. If ohmmeter reads zero ohms,

wire is okay. Check for faulty sensor. If ohmmeter reads infinity,

sensor is okay. Check for open circuit.

DTC 1-2-3 & 1-2-5 DRIVER’S OR PASSENGER’S SIDE TEMP.

SENSOR CIRCUIT SHORTED TO GROUND

1) Turn ignition off. Install test unit and adapter between

ECC control module and harness connector. 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 from ECC control module. Disconnect

appropriate side temperature sensor connector. See Figs. 6 and 7.

Connect ohmmeter to test unit pins No. 10 and 12 to check driver’s

side temperature sensor and terminals No. 10 and 13 to check

passenger’s side temperature sensor.

3) If ohmmeter reads zero ohms, check for short circuit

between driver’s or passenger’s side temperature sensor and ECC

control module. See WIRING DIAGRAMS.

4) To check driver’s or passenger’s side temperature sensor,

ensure harness connector from sensor is disconnected. Connect ohmmeter

between temperature sensor terminal No. 3 (Brown wire) and terminal

No. 5 (Green or Yellow wire). Resistance should be 8000-12,000 ohms.

If resistance is not as specified, replace faulty temperature sensor.

Fig. 6: Identifying Passenger Compartment Temperature Sensor

Connector & Component Terminals

Courtesy of Volvo Cars of North America.

Fig. 7: Locating Passenger’s Side Temperature Sensor

Courtesy of Volvo Cars of North America.

DTC 1-2-4 & 1-2-6 DRIVER’S OR PASSENGER’S SIDE TEMP.

SENSOR CIRCUIT OPEN OR SHORTED TO POWER

1) Ensure DTCs 1-2-2, 1-2-4, 1-2-6, 2-1-1, 2-2-1, 2-3-1, 2-3-

3 or 2-3-5 are not present at the same time. If any of these codes are

present at the same time, check for an open circuit in the common

ground wire. If only DTC 1-2-4 or 1-2-6 is present, go to next step.

2) Turn ignition off. Install test unit and adapter between

ECC control module and wiring harness. Turn ignition on. Connect

voltmeter to test unit pins No. 10 and 12 to check driver’s side

temperature sensor and terminals No. 10 and 13 to check right side

temperature sensor.

3) Voltage should be about 2.6 volts at 68

F (20

C). If

voltage reading is 5 volts, check for open circuit in passenger’s side

temperature sensor then go to next step. If voltage reading is 12

volts, repair short circuit between sensor harness terminal No. 5

(Green or Yellow wire) and ECC control module.

4) Turn ignition off. Disconnect Adapter (981 3194) from ECC

control module. Disconnect temperature sensor connector. Install

jumper wire between sensor harness terminals No. 3 (Brown wire) and

No. 5 (Green or Yellow wire).

5) Connect ohmmeter between test unit pins No. 10 and 12 for

driver’s side temperature sensor or pins No. 10 and 13 for passenger’s

side temperature sensor. If ohmmeter reads zero ohms, wire is okay.

Check for faulty sensor. If ohmmeter reads infinity, sensor is okay.

Check for open circuit.

6) To check sensor resistance, disconnect sensor harness

connector. Connect ohmmeter between sensor terminals No. 3 (Brown

wire) and No. 5 (Green or Yellow wire). Resistance should be 8000-12,

000 ohms. If resistance is not as specified, replace faulty sensor.

Clear and recheck for DTC.

DTC 1-3-1 & 1-3-3 DRIVER’S OR PASSENGER’S SIDE DUCT

TEMP. SENSOR CIRCUIT SHORTED TO GROUND

1) Ensure ignition is off. Connect test unit to ECC control

module. Check ground circuits 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.

2) Ensure ignition is off. Disconnect A/C control unit, but

leave test unit connected to A/C control unit connector. Disconnect

driver’s and passenger’s side duct temperature sensor connectors. See

Fig. 8.

3) Check wiring resistance for driver’s side duct temperature

sensor by measuring between test unit pins No. 56 and 47. Check wiring

resistance for passenger’s side duct temperature sensor by measuring

between test unit pins No. 56 and 48. If ohmmeter indicates no

continuity, go to next step. If ohmmeter indicates continuity, check

wiring for short to ground.

4) Ensure ignition is off. Ensure driver’s and passenger’s

side duct temperature sensors are still disconnected. Measure

resistance directly between duct temperature sensor terminals. See

Fig. 9. Resistance should be about 8000-12,000 ohms. If resistance is

not 8000-12,000 ohms, replace duct temperature sensor(s).

Fig. 8: Locating Duct Temperature Sensor

Courtesy of Volvo Cars of North America.