Volvo 850. Manual - part 64

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.

Fig. 15:  Locating Power Stage & A/C Relay

Courtesy of Volvo Cars of North America.

         DTC 4-1-9 ECC POWER STAGE EMITTING FAULTY DIAGNOSTIC SIGNAL

         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. Connect voltmeter between test unit pins

No. 6 and 27. Voltmeter should indicate 3 volts. If voltmeter

indicates one volt, there is no control signal to power stage. See DTC

4-1-8, NO CONTROL SIGNAL TO ECC POWER STAGE. If voltmeter indicates 4

volts, there is excessive voltage from power stage. See DTC 4-1-1,

PASSENGER COMPARTMENT FAN OVERCURRENT OR SEIZED FAN.

         3) If voltmeter indicates 12 volts, check wire at ECC control

module terminal A27 (Violet/White wire) for a short to voltage. See

Fig. 10. If voltmeter indicates zero volts, wire has an open circuit

or is shorted to ground. Go to next step.

         4) Ensure ignition is off. Disconnect power stage 4-pin

connector. See Figs. 14 and 15. Check Violet/White wire between power

stage connector terminal 2A and ECC control module terminal A27 for a

short to ground or open circuit. If wire is okay, go to next step.

         5) Reconnect power stage 4-pin connector. Turn ignition on.

Connect voltmeter between test unit pins No. 6 and 5. If battery

voltage is present, go to next step. If zero volts are present, wire

is shorted to ground.

         6) Ensure ignition is off. Disconnect power stage 4-pin

connector. Connect ohmmeter between test unit pin No. 5 and power

stage connector terminal 3A. If ohmmeter indicates continuity, replace

power stage. If ohmmeter indicates no continuity, check wiring for an

open circuit and repair as necessary.

         DTC 4-2-0 ECC CONTROL MODULE FAULT, PROGRAM MEMORY

         Erase DTC. Start and run engine. Turn engine off, leaving

ignition on. Check if DTC returns. If DTC returns, replace ECC control

module. Perform damper motor limit self-adjustment under  TEST MODE 4.

         DTC 5-1-1 SELF-ADJUSTMENT OF DAMPER MOTOR

         LIMIT POSITIONS NOT CARRIED OUT

         Erase DTC. ECC control module is programmed to carry out

self-adjustment of damper motor limit positions. Drive vehicle over 20

MPH for a few minutes. ECC control module will carry out self-

adjustment while driving. Stop vehicle and leave ignition on at least

2 minutes to enable ECC control module to store all values.

         TESTING

WARNING: To avoid injury from accidental air bag deployment, read and

         carefully follow all SERVICE PRECAUTIONS and DISABLING &

         ACTIVATING AIR BAG SYSTEM procedures in the AIR BAG RESTRAINT

         SYSTEM article in the ACCESSORIES/SAFETY EQUIPMENT section.

         A/C SYSTEM PERFORMANCE

         1) Ensure compressor drive belt is okay, fan motor runs at

all speeds, and that temperature vents shut completely with

temperature switch in full cooling position.

         2) Ensure that all air comes from panel vents with mode

control on vent position, recirculation motor is working, and

condenser fan and cooling fan are working.

         3) Start and warm engine to normal operating temperature.

Ensure compressor clutch engages when A/C is turned on. Set

temperature switch to full cold position, place mode control to vent

position, turn on recirculate air switch and blower fan switch high

speed.

         4) Close engine hood, doors and windows. Run engine at 1500-

1600 RPM. Place thermometer in one of the center panel vents. Allow

system to stabilize for at least 8 minutes. Check temperature in

center panel vent. See A/C SYSTEM PERFORMANCE SPECIFICATIONS table.

A/C SYSTEM PERFORMANCE SPECIFICATIONS (1)

Ambient Temp. 



F (



C)     Outlet Air Temp. 



F (



C)

68 (20)  ............................  41-48 (5-8)

86 (30)  ............................  41-48 (5-8)

104 (40)  ..........................  46-54 (8-12)

(1) - Based on a relative humidity of 40-60%.

         A/C RELAY CHECK

         Remove relay. Connect battery positive lead to relay terminal

No. 1 and negative lead to relay terminal No. 3. Continuity should be

present between relay terminals No. 2 and 4. See  Figs. 12 and 15. If

continuity is not present, replace relay.

         ON-BOARD DIAGNOSTIC UNIT CHECK

         1) Turn ignition on. Press button on diagnostic unit "A". See

Fig. 2. LED should illuminate. If LED does not illuminate, go to next

step. If LED illuminates, but no code(s) is present, go to step 4).

         2) Turn ignition off. Remove connector from underside of

diagnostic unit "A". Connect voltmeter between terminal No. 4 of

diagnostic unit "A" and ground. Turn ignition on. Battery voltage

should be present. If battery voltage is present, go to next step. If

battery voltage is not present, check for blown fuse No. 33 or for

open circuit between fuse block and terminal No. 4.

         3) Turn ignition off. Connect ohmmeter between terminal No. 8

of diagnostic unit "A" and ground. Continuity should exist. If

continuity exists, replace diagnostic unit and retest. If continuity

does not exist, check ground connection.

         4) Turn ignition off. Disconnect selector cable from

diagnostic unit "B". Turn ignition on. Connect voltmeter between

terminal No. 1 of diagnostic unit "B" and ground. Voltage should be

about 10 volts. If voltage is as specified, replace diagnostic unit.

If voltage is not as specified, check for open or shorted circuit

between ECC control module and terminal No. 1 of diagnostic unit "B".

         PIN VOLTAGE TESTS

NOTE:    Perform all voltage tests using Digital Volt-Ohmmeter (DVOM)

         with a minimum 10-megohm input impedance.

         Pin voltage chart is supplied to reduce diagnostic time.

Checking pin voltage at ECC control module determines whether it is

receiving or transmitting proper voltage signals. Charts may also help

determine if control unit wiring harness has short or open circuit.

ECC CONTROL MODULE PIN ASSIGNMENTS CONNECTOR "A"









































































 (1)    



         Function/Description           



  Voltage Value   





Pin No. 



                                        



                  







   1    



 Power Supply To ECC Control Module     



 Battery Voltage