Diagnostics and testing of seats (Discovery 3)

General information

Seat diagnostics can be divided into three main parts: seat movement, memory and seat heating.

The seat heating is controlled by the Automatic Temperature Control Module, so some diagnostic trouble codes (DTCs) are the same as the climate control system codes.

There are several related systems such as mirror and steering column movement systems that will also be discussed in this section.

Information on the systems and their operation can be found in the relevant section of the service station manual.

Inspection and verification

1. Check the validity of the customer's complaint.

2. Visually inspect for obvious mechanical and electrical problems.

Foreign objects may become caught in the seat rails and frames.

Mechanical elements

Electrical factors

Seat runner guides Seat frame Seat movement switch status and setting Seat heating switch status and installation Electric motor condition and installation (electric motors) seats Steering column switch condition and installation Steering column condition and installation Condition and installation of the outside mirror switch Condition and installation of exterior mirrors

Battery status and charging Fuses and fuses Wiring harnesses and electrical connectors Seat movement switch(es) Seat heating switch(es) Seat heating elements Seat motor(s) Seat module(s) Memory function control module(s) Steering column switch Steering column electric motor Exterior mirror switch(es) Electric motor(s) for outside mirrors Ignition switch Battery Junction Box (BJB) Central Junction Box (CJB) LIN electrical circuit (Local interconnect network)

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3. If an obvious cause for the problem you identified or the customer described is found, correct it before proceeding with further actions. (if possible).

4. Use the approved diagnostic system or scan tool to retrieve all diagnostic trouble codes (DTCs) before referring to the Symptom Chart or DTC Index.

Since DTCs are stored in more than one module, a full vehicle data read is recommended.

Clear all DTCs after troubleshooting.

Table of signs of malfunction

NOTE: Seat movement reference information applies to each front seat.

Sign of malfunction	Possible reasons	Action
The seat will not move when the switch is pressed (forward, backward, tilt, etc.)	The guide or mechanism is jammed Switch malfunction Electric motor failure Automatic thermal switch is activated Electrical circuit failure Module failure	Check for obstacles in the guides, mechanisms, etc., and repair them if necessary. The automatic thermal switch can be activated in the event of a malfunction of the electric motor or mechanism. Check for DTC codes that indicate a malfunction of the switch, motor, or module.
The steering column does not move when the switch is pressed	Switch malfunction Electric motor failure Clutch/solenoid failure	Check for DTCs that indicate a faulty switch, motor, or clutch/solenoid.
Mirrors do not move when the switch is pressed	Mechanical failure Switch malfunction Electric motor failure Electrical circuit fault: high resistance Electrical circuit fault: short circuit to ground in electrical circuit	Checking the mirrors is described in the relevant section of the service station manual.
The stored seat/steering column/mirror position is not restored	Battery voltage is less than 10.5 V The position is not stored in memory The switch is pressed during operation of the "one-touch" memorized position recovery function. EEPROM failure	Before assuming a faulty memory element, check the operation of the switch and refer to the symptoms described above. Make sure there is sufficient battery voltage. Make sure the desired position is correctly stored in memory. Make sure the procedure for storing/restoring the stored position is carried out correctly. Refer to the relevant section in the workshop manual.
The function does not work "Lazy entry"	Remote transmitter malfunction (power supply, transmitter programming, etc.) See the list for the section "The stored position is not restored"	Check if the remote transmitter controls the central locking etc. If yes, the fault is not in the transmitter. Refer to the section "Memorised position is not restored"
Login/Logout mode does not work	The switch is not in AUTO mode. Switch malfunction Electric motor failure Clutch/solenoid failure	Make sure the function is enabled and the switch is in the correct position. Check for DTCs indicating a faulty switch, motor, or clutch/solenoid.
The seat does not heat up	Switch malfunction Fuses and fuses Electrical circuit failure Temperature sensor Battery voltage is greater than 16.5 V	Check the LEDs on the switches when checking the operation of the switches. If the LEDs light when the switch is pressed, the switches are receiving power and the switches are operating at least within one level. Check the electrical circuits of the seat heater. Refer to the electrical manual. Check the operation of the temperature sensor. If the battery voltage is greater than 16.5 V for more than 5 seconds, the seat heating system is suspended. Refer to the appropriate section in the workshop manual.
Part(s) of the seat do not heat up	Element failure	Each seat contains up to three elements. If the rest of the seat is working properly, check the connections and continuity of the element. Refer to the electrical manual.