Cooling System: Diagnosis Saab 9-5 I рестайлинг 2

Diagnostics

If the coolant temperature lies outside the limits or if coolant temperature information is not given, the DICE starts low speed running after 5 seconds. This prevents engine overheating.

A diagnostic trouble code is generated in Trionic. For further information refer to "ENGINE MANAGEMENT SYSTEM, TRIONIC 4-CYL.", FAULT DIAGNOSIS .

The DICE receives information on the coolant temperature from TRIONIC.

The radiator fan/fans are activated as follows

Scheme 2

1. Low speed Activated when the coolant temperature reaches 99°C and stopped when the temperature drops to 96°C.
2. High speed Activated when the coolant temperature reaches 113°C and stopped when the temperature drops to 109°C.

When A/C is requested, some conditions must be fulfilled in the DICE as well as TRIONIC for the A/C compressor clutch to operate. For further information with regards to A/C and its control, see A/C SYSTEM (2006) or HEATING AND VENTILATION, A/C (2007) .

For further information on the coolant temperature sensor, refer to COOLANT TEMPERATURE SENSOR (2006) or TEMPERATURE SENSOR, ENGINE COOLANT (2007) .

When the A/C coupling is active, the radiator fans are activated according to the following conditions

1. Low speed Activated when the outside temperature exceeds 22°C and stopped when the outside temperature falls below 20°C.
2. Low speed Vehicle speed is below 38 km/h while A/C pressure is between 9 and 18 bar. Low speed running stops when vehicle speed rises above 40 km/h or A/C pressure drops below 7 bar.
3. High speed A/C pressure is above 18 bar. High speed running stops when A/C pressure is below 14 bar.

To understand the operation of the radiator fan, it is important to note that it can be activated differently at the same value (within certain preset limits), depending on whether the value is rising or falling.

If coolant temperature is 98°C, for instance, low speed will be activated if the temperature was previously 100°C or above and has now fallen to 98°C. However, if low speed had not been activated and the coolant temperature is 98°C, low speed will not be activated.

Scheme 3

The DICE receives information on the coolant temperature from TRIONIC with the ignition OFF, after 30 seconds and after 1 minute when the ignition switch is in the OFF position.

In order to receive this information, the DICE needs to keep the MIU active for one minute. From this information, the DICE can activate low speed running for a maximum of 3.5 minutes.

Note that only low speed running is activated with the ignition OFF.

Diagnostic trouble code table

DIAGNOSTIC TROUBLE CODE TABLE

Scheme 4

Fault symptoms

Vehicle with one radiator fan

1. Fan runs permanently at high speed (even with ignition OFF), which can cause excessive noise from the fan.
2. Radiator fan not working, can lead to engine overheating.

Vehicle with two radiator fans

1. Radiator fan runs continuously at low speed.
2. Radiator fan not working. On high speed, the left-hand fan does not work. This can cause engine overheating and reduced A/C performance.

Diagnostic help

The control module output can be activated with the tester.

Vehicle with one radiator fan

1. On high speed running, the fan runs at low speed which can cause engine overheating.
2. On low speed running, the fan runs at high speed which can lead to excessive noise from the radiator fan.

Vehicle with two radiator fans

1. On high speed running, only the right-hand radiator fan runs. Low speed running is OK. This can lead to engine overheating and reduced A/C performance.
2. On low speed running, the left-hand fan runs at high speed, which can lead to excessive noise from the radiator fan. High speed running is OK.

The control module output can be activated with the tester.

Vehicle with two radiator fans

1. The right-hand fan runs at high speed continuously (even with the ignition OFF), which can lead to excessive noise from the radiator fan.
2. Low speed running is OK but on high speed the right-hand fan is not working. This can lead to engine overheating and reduced A/C performance.

The control module output can be activated with the tester.

Radiator Fan Diagnostics

The Saab tester can be used to activate the relay outputs concerned as well as low speed and high speed operation. If no information on the coolant temperature is supplied, low speed operation will start. Check the wiring by jiggling the wiring harness at several points and in different directions to reveal intermittent breaks and short-circuits in the wiring harness. Observe the multimeter, test lamp or diagnostic instrument while doing this.

"Coolant level low" message on SID.

Diagnostic procedure

When rectifying a coolant leak, it is important that not only the hose clip is changed. Make also sure there are no defects in the hose and replace it if necessary.

Fault diagnosis procedure is not available.

Scheme 5

Radiator fan operation faulty

The tester can be used to activate the relay outputs concerned as well as low speed and high speed operation.

If no information on the coolant temperature is supplied, low speed operation will start.