Fault code 1340: Diagnosis/troubleshooting

NOTE: Visual inspection: In the next troubleshooting section, please check first that the affected pins on the driver's door control unit plug connection are neither damaged nor corroded. The wiring and plugs of the affected components must also be checked for external damage and proper contact. Repair damaged or corroded pins if possible, otherwise replace affected pins. Repair or replace damaged wires.

NOTE: Sporadic faults: In the event of faults that occur sporadically, the wiring positions that are linked to moving parts on and in the vehicle must be checked for each system. Various statuses that can cause faults must be simulated with the help of the wiring diagram.

NOTE: Battery voltage: A battery voltage of between 11.4 and 14.5 V is required for the following troubleshooting procedure. This must be checked and provided, if necessary. On the vehicle electrical system, the voltage to the fuse (input side) must be guaranteed.

NOTE: 'Short circuit to ground' → The fault is detected if there is ground potential for more than five minutes on plug A, pin 8

NOTE: The following Diagnosis/troubleshooting should be performed with the mirror adjustment switch in position A (driver's door mirror) and position B (passenger's door mirror).

WORK INSTRUCTION CHART

Work instruction			Display OK	If not OK
1	Check status of 'mirror adjustment switch'	Use the Porsche System Tester II No. 9588 to switch to the menu 'Input signals/Mirror adjustment switch' Press the switch in all possible positions	Status of 'mirror adjustment switch' stays in one of the following positions: 'X +' (Right) 'X -' (Left) 'Y +' (Up) 'Y -' (Down) Go to step 2
			Status of 'mirror adjustment switch' in at least one position changes to: 'Implausible signal' Go to step 5
			Status of 'mirror adjustment switch' (switch not pressed) is: 'Implausible signal' Go to step 2
			Status of 'mirror adjustment switch' changes according to switch actuation: 'X +' (Right) 'X -' (Left) 'Y +' (Up) 'Y -' (Down) Go to step 8
2	Check mirror adjustment switch	Pull plug off 'mirror adjustment switch'	Status of 'mirror adjustment switch' changes to: 'Not actuated' Go to step 8	Go to step 3
3	Check line from driver's door control unit to mirror adjustment switch for short circuit to ground	Switch off ignition Pull plug A off driver's door control unit Measure resistance between pin 8 of control unit plug A and ground	∞ Ω Go to step 4	Repair line → End
4	Check line from driver's door control unit to mirror adjustment switch for short circuit	Measure resistance between pins 8 and 17 of control unit plug A	∞ Ω Go to step 8	Repair line → End
5	Check operation of mirror adjustment switch	Pull plug off mirror adjustment switch Measure resistance at the mirror adjustment switch between pins 6 and 8 Press mirror adjustment switch in all possible positions	'Not actuated' ∞ Ω 'X +' (right) 230 to 250 Ω 'X -' (left) < 5 Ω 'Y +' (up) 2,650 to 2,750 Ω 'Y -' (down) 800 to 840 Ω Go to step 6	Go to step 7
6	Check line from driver's door control unit to mirror adjustment switch for open circuit	Measure resistance between pin 8 of control unit plug A and pin 6 of mirror adjustment switch plug Measure resistance between pin 17 of control unit plug A and pin 8 of mirror adjustment switch plug	< 5 Ω Go to step 8	Repair line → End
7	Replace mirror adjustment switch		→ End
8	Replace driver's door control unit		→ End