Description

The safety computer has detected an illegal activation of the third gear while the vehicle is driving. This condition is characterised by the solenoid valve condition DK activated and an output frequency greater than 30000 Hz. This condition may lead to the unmotivated braking of the vehicle.

Effects on the driving operation

Driving operation is blocked for safety reasons. The transmission assumes a safe state.

Possible causes

Faulty solenoid valve wiring.

Defective solenoid valve.

Potential shift due to an inadmissibly high line resistance of the ground cable.

Faulty information on driving direction.

Faulty activation of solenoid valve by the function computer.

Function of the safety computer

The safety computer (S-CPU) monitors safety-relevant signals which the function computer (F-CPU) sends or receives. If the safety computer detects an inadmissible condition, it initiates a reset of the function computer. During that time, the transmission system is in a safe mode (neutral).

Driving operation is only released if both the function computer AND the safety computer give their approval simultaneously. After the release the safety switch in the transmission control unit is closed and the ground of the solenoid valves is connected to the battery ground. Only then can the solenoid valves be activated and enable driving operation.

Connector pin assignment of transmission control unit

Pin	Stecker A	Stecker B	Stecker C	Stecker D
1	SHIELD	EK	FLEXI-1	-BATT
2	TIM+	DK	---	IGN
3	TIM-	SK	FLEXI-3	FLEXI-11
4	N1+	RBK	FLEXI-4	K-LINE
5	N1-	TB	FLEXI-5	CAN1-H
6	N2+	---	FLEXI-6	CAN1-H
7	N2-	RBG	FLEXI-7	CAN-SHLD
8	N3+	PB	FLEXI-8	CAN1-L
9	N3-	WR	FLEXI-9	CAN1-L
10	---	WP	FLEXI-10	CAN2-H
11	---	---	FLEXO-2H	CAN2-H
12	EKM	FLEXI-12	FLEXO-4H	CAN2-L
13	DKM	S-GND	FLEXO-3H	CAN2-L
14	SKM	OIL-LVL	FLEXO-5L	CAN1-R
15	PBM	T-SUMP	---	---
16	TBM	---	---	FLEXO-1L
17	RBKM	T-CONV	---	CAN2-R
18	MVM-GND	MV-GND	---	+BATT

Pin assignment of transmission connector

Pin	Name	Pin	Name	Pin	Name
1	S-GND	14	RBK	27	EKM
2	MV-GND	15	RBG	28	PBM
3	MV-GND	16	TB	29	RBKM
4	---	17	WR	30	TBM
5	T-CONV	18	---	31	MVM-GND
6	T-SUMP	19	---	32	N1+
7	OIL-LVL	20	---	33	N1-
8	P-DIFF	21	TIM-	34	N2+
9	SK	22	TIM+	35	N2-
10	DK	23	---	36	N3+
11	EK	24	SHIELD	37	N3-
12	PB	25	SKM
13	WP	26	DKM

Place of action

No description available.

Instruction

Check plug connections, cabling and solenoid coil.

Should the fault not disappear, please contact the VOITH customer service.

Evaluation of SV states

Above a voltage of 5 V the solenoid coils activate the hydraulic valves. The safety computer recognises the condition "activated" already above a voltage of 2.9 V. This ensures that safety-crucial conditions of solenoid valves are detected before they can cause misshifts in the transmission.

Setting conditions of the event

-Voltage DK (min. 0.2s) > 5V

- Output frequeny > 3000 Hz.

Test conditions of the event

No description available.

Final function check

If the defective component cannot be clearly identified, you should try to reproduce the fault:

• Reinstall the component in the vehicle.
• Test the function.

After the fault has been eliminated, the following steps have to be carried out:

• Conduct a test drive with function check.
• Read out the fault memory.
• Check the transmission for leaks.
• Perform a final visual inspection.

These steps are necessary to ensure the entire vehicle functions.

See also:

		Aftersales service index