Electronic power shift (EPS) diagnosis operational check without tester on display

AD26.20-W-3003B

Electronic power shift (EPS) diagnosis operational check without tester on display

7.11.97



The function check permits a limitation of the fault possibilities and should, as a basic principle, be carried out before operations on the EPS system. Faults are shown by the illumination of the display (1) and code numbers (2) in the display.



The connection of secondary electric consumers to the existing EPS fuses may, in the event of short-circuit or overloading, leave the EPS inoperative.

Electronic power shift (EPS), diagnosis previous knowledge

AD26.20-W-2001B

EPS diagnostic tools

AD26.20-W-2001-01A



On-Board voltage 24 V (Specific density 1.16, with undervoltage fault code 17).



Indicator lamp for secondary consumers must be out.



Compressed air at least 5.5 bar.

Function check

Test step / scope of test

Operation / requirement

Specified value

Possible cause / remedy

1

Display function

Ignition: ON

All figures / symbols illuminate

approx. 4 s.

Fuse F11 defective

AD26.20-W-6001-21B

AD26.20-W-6001-22A

AD26.20-W-6001-23B

2

Warning buzzer function and D+ actuation

Ignition: ON

Start engine

Charge indicator lamp goes out

AD26.20-W-6001-20A

AD26.20-W-6001-24B

3

Shift processes

Ignition: ON

Actuate clutch pedal

Shift through gears N, 1-8, R.

Reverse gear with function knob.

Actuate splitter switch.

All gears (N, 1-8, R, splitter) are displayed according to actuation.

Actuate transmission tooth on tooth (actuate clutch pedal again if necessary / briefly start engine and repeat test step).

Check compressed air supply and test step 4.

4

Check whether fault code no. apperas in the display



– The fault codes no. 1-18 show stored electrical faults

– Faults occurring intermittently (loose contact) are also only displayed intermittently during driving.

– The fault lamp lights up in conjunction with fault codes no. 1-18

Ignition: ON

Note illuminating code nos. as these may be erased after the following programming.

Carry out programming in the following sequence:

1. Switch off all electric consumers.

2. Switch off ignition (for at least 15 s).

3. Actuate clutch pedal and hold.

4. Hold shift lever in neutral position.

5. Switch on ignition.

The programming process lasts approx. 15 seconds.

The following codes may appear in the display during programming:

1a Fault codes 21-26 appear in display only during programming.

1b Previously displayed (noted) fault codes no. 1-18 do not appear in display during programming.

Fault is constantly present.

In the sequence:

1. Remove all previously displayed fault codes 1-18

AD26.20-W-6001B

and then carry out programming.

2. Check electrical and pneumatic connections on transmission for correct connection.

3. Mechanical defect in transmission.

The fault code no. is shown again in the display after switching off engine and switching on ignition again.

Fault codes no. 21-26 show deviations from the sensor specified travel values during programming.



– When installing a new control unit, part no. 006 545 6632 or 006 545 6732, only 8 and N are displayed when programming.

– The driver or customer should also be informed about the programming process.

– Re-program in the event of undervoltage or jump-starting. With undervoltage programming should take place with jump-starting batteries.

2. New fault codes no. 21-26 appear in display.

Fault codes no. 1-18 do not appear in display.

In the sequence:

1. Check electrical and pneumatic connections on transmission for correct connection.

2. Sensor outside travel tolerance (replace on trial), refer to

AD26.20-W-2001-15B

(fault code assignment table).

3. Mechanical defect in transmission

3. If programming has not taken place:

Previously displayed (noted) fault codes no. 1-18 re-appear in display.

Moving off and stopping in 4th gear or higher with rubbing clutch also shows fault code 7 in display.

Fault is constantly present. Carry out test steps in accordance with fault code no. displayed:

AD26.20-W-6001B

4. Previously displayed (noted) fault codes no. 1-18 no longer appear in display.

N. Neutral position is shifted/displayed following programming.

Fault is currently not present. Check components and plug connections appropriate to displayed fault code no. for correct functioning / loose contact:

AD26.20-W-6001B

5. Before and after programming no display in display, yet complaint on transmission.

1. Check electrical and pneumatic connections on transmission for correct connection.

2. Mechanical defect in transmission.

3. Possibly change control electronics on trial.