Retarder control RS (RET) diagnosis, troubleshooting

AD43.30-W-5000A

Retarder control RS (RET) diagnosis, troubleshooting

9.7.97

Retarder control RS (RET) diagnosis, previous knowledge

AD43.30-W-2000A



Hydraulic retarder function description contents

Model 375.4, 944, 950, 952, 953, 954

GF43.30-W-0999A

Model 930, 932, 933, 934

GF43.30-W-0999MP



 Fuses OK

 Battery voltage 18,0 to 32,0 volts

 Reservoir pressure for compressed-air system more than 9 bar

Troubleshooting

Complaint

Possible cause

Note

Remedy

No retarder braking effect

Retarder control (RS) control unit (A20) defective

Model 930, 932, 933, 934

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder control unit (A20) defective

Model 375.4, 944, 950, 952, 953, 954

Fault memory (fault code list) see STAR DIAGNOSIS

Oil leaks at retarder

Visual inspection

Oil level not OK

Retarder - checking, correcting oil level

AP43.30-W-4310A

Compressed air supply to retarder interrupted

Check supply compressed air

Engine control/permanent brake operating lever defective

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder proportioning valve (Y44) or temperature limiting defective

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Limiting of braking torque by incorrect values of retarder oil temperature sensor (B66) or coolant temperature sensor (B65)

Model 930, 932, 933, 934

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Limiting of braking torque by incorrect values of oil temperature sensor (B66) or of coolant temperature sensor (B65)

Model 375.4, 944, 950, 952, 953, 954

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Retarder braking effect too low

Oil level not OK

Retarder - checking, correcting oil level

AP43.30-W-4310A

Damping plate leaky

Check damping plate for cracks and replace if necessary

AR43.30-W-0001A

Limiting of braking torque by incorrect values of retarder oil temperature sensor (B66) or coolant temperature sensor (B65)

Model 930, 932, 933, 934

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Limiting of braking torque by incorrect values of oil temperature sensor (B66) or of coolant temperature sensor (B65)

Model 375.4, 944, 950, 952, 953, 954

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Temperature limiting defective

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Retarder proportioning valve (Y44) defective

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Voith retarder system test R115 using STAR DIAGNOSIS

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder braking efficiency is uneven.

Coolant in retarder due to defective heat exchanger

Check heat exchanger

AR43.30-W-0007A

Retarder proportioning valve (Y44) defective

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Retarder oil temperature sensor (B66) or coolant temperature sensor (B65) has loose contact

Model 930, 932, 933, 934

Fault memory (fault code list) see STAR DIAGNOSIS

Oil temperature sensor (B66) or coolant temperature sensor (B65) has loose contact

Model 375.4, 944, 950, 952, 953, 954

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder does not switch off after braking

Shaped breather does not open after brake application

Inspect shaped breather

AR43.30-W-0004A

Retarder proportioning valve (Y44) defective

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Retarder switch-off delay after brake application

Silencer (breather) severely soiled

Muffler

Remove/install

AR43.30-W-0005A

Shaped breather does not open after brake application

Inspect shaped breather

AR43.30-W-0004A

Oil loss through muffler (vent)

Profile ventilation does not close

Inspect shaped breather

AR43.30-W-0004A

Transmission oil level not OK

Inspect transmission oil level

Correct transmission oil level

Oil level not OK

Retarder - checking, correcting oil level

AP43.30-W-4310A

Coolant in retarder due to defective heat exchanger

Check heat exchanger

AR43.30-W-0007A

Temperature limiting sets in too soon

Coolant temperature too high due to defective cooling system components

Check cooling system complete

Repair or replace defective components

Coolant temperature too high due to an oil fouled or calcified cooling system

Remove grease and scale in cooling system

Model 950, 952, 953, 954 with ENGINE 906.9

AR20.00-W-1030A

Model 950, 952, 953, 954 with ENGINE 541.9

Models 950, 952, 954 with engine 542.9

AR20.00-W-1030B

Model 375.4, 944 with engine 457.9

AR20.00-W-1030C

Model 930, 932, 933, 934 with ENGINE 541.9

Models 930, 932, 934 with engine 542.9

AR20.00-W-1030G

Model 950, 952, 953, 954 with ENGINE 926.9

AR20.00-W-1030J

Temperature limiting defective

Retarder oil temperature sensor (B66) or coolant temperature sensor (B65)

Model 930, 932, 933, 934

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Oil temperature sensor (B66) or coolant temperature sensor (B65) defective

Model 375.4, 944, 950, 952, 953, 954

Retarder control RS (RET), testing of electrical system

AD43.30-W-6000A

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder control (RS) control unit (A20) defective

Model 930, 932, 933, 934

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder control unit (A20) defective

Model 375.4, 944, 950, 952, 953, 954

Actuation of all retarder brake stages not possible

Engine control/permanent brake operating lever defective

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder control (RS) control unit (A20) defective

Model 930, 932, 933, 934

Fault memory (fault code list) see STAR DIAGNOSIS

Retarder control unit (A20) defective

Model 375.4, 944, 950, 952, 953, 954

Fault memory (fault code list) see STAR DIAGNOSIS

"RS (RET)" without fault code is shown in the display matrix

Communication error between retarder control (RS) control unit (A20) and base module (GM) (A7)

As of approx. manufacture year 1999 a fault is displayed in the driver information system

Fault memory (fault code list) see STAR DIAGNOSIS