Cooling System: Diagnosis Saab 9-5 I рестайлинг

Diagnostic trouble code table

DIAGNOSTIC TROUBLE CODE

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. Check the wiring

Jiggle 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.

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.

Table of fault symptoms

FAULT SYMPTOMS

Scheme 3

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.

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, see Diagnostic trouble code table under FAULT DIAGNOSIS for further information.

The DICE receives information on the coolant temperature from TRIONIC.

The radiator fan/fans are activated as follows

Scheme 4

1. Low speed Activated when the coolant temperature reaches 100°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 the A/C is requested, there are some conditions in DICE and in TRIONIC that must be fulfilled before the A/C compressor clutch is engaged. For further information about the A/C and its control see TECHNICAL DESCRIPTION , A/C system.

For further information about the engine coolant temperature sensor see TECHNICAL DESCRIPTION , ENGINE COOLANT TEMPERATURE SENSOR .

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 5

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.

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, see FAULT DIAGNOSIS for further information.

The DICE receives information on the coolant temperature from TRIONIC.

The radiator fan is activated as follows

Scheme 6

1. Low speed Activated when the coolant temperature reaches 97°C and stopped when the temperature drops to 93°C.
2. High speed Activated when the coolant temperature reaches 107°C and stopped when the temperature drops to 103°C.

When the A/C is requested, there are some conditions in DICE and in TRIONIC that must be fulfilled before the A/C compressor clutch is engaged. For further information about the A/C and its control see TECHNICAL DESCRIPTION , A/C system.

For further information about the engine coolant temperature sensor see TECHNICAL DESCRIPTION , " ENGINE COOLANT TEMPERATURE SENSOR ".

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 95°C, for instance, low speed will be activated if the temperature was previously 97° C or above and has now fallen to 95°C. However, if low speed had not been activated and the coolant temperature is 95°C, low speed will not be activated.

Scheme 7

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 ign