Steering and Suspension: Service Precautions

Tests/notes for four-wheel drive

Information for four-wheel drive vehicles

Information for four-wheel drive vehicles

Balancing wheels on vehicle

When fine-balancing wheels on the vehicle, all four wheels must be raised and must be able to turn freely.

If a fault occurs in PSM (Porsche Stability Management), read out the fault memory before fine-balancing.

After fine-balancing, the fault memory of the PSM control unit must be erased.

Controlled four-wheel drive (PTM) on the 911 Turbo

The PTM control unit (PTM = Porsche Traction Management) is specifically designed to suit the approved tire dimensions. The use of unapproved tires can result in different wheel speeds and can affect vehicle handling or cause PTM to switch off.

Power measurements/function tests on the 911 Turbo

Power measurements on the 911 Turbo (997) - under full load - are not approved by Porsche!

Function tests and partial-load measurements - without full load - are permitted. These tests can only be carried out on four-roller-type test stands.

Power measurements on the 911 Carrera 4/911 Carrera 4S

Power measurements can only be carried out on four-roller-type test stands.

Brake test

Brake tests can only be carried out on roller-type test stands or plate test stands.

The ignition must be switched off on the 911 Turbo! This is necessary because of the controlled four-wheel drive function - Porsche Traction Management (PTM).

If no four-wheel drive test stand (roller-type test stand) is available, the following limit values must not be exceeded for conventional roller-type test stands:

^ Test speed: max. 8.0 km/h.
^ Test duration: max. 20 seconds.

Handbrake test on the 911 Turbo

Handbrake tests on the roller brake tester can only be carried out with the ignition switched off on the 911 Turbo.

This is necessary because of the controlled four-wheel drive function (PTM).

Towing

The vehicle must be on all four wheels during towing or must be transported on a car transporter or on a trailer.

One axle (either front or rear) can only be raised if the drive shaft (cardan shaft) has been removed. Alternative (instead of removing the cardan shaft): The vehicle would have to be raised to such an extent that the wheels on the raised axle can turn freely while the vehicle is being towed. The gearshift lever must be in neutral. The ignition must be switched off. The steering lock (ELV = electric steering column lock) must first be released (switch on ignition, switch it off again and then do not remove the ignition key).

For vehicles with Tiptronic transmission, sufficient lubrication of the transmission is not guaranteed when the engine is not running. To prevent transmission damage, the following points must also be observed:

^ Move selector lever to position N.
^ The ignition must be switched off. Release the steering lock (ELV) beforehand.
^ Do not exceed a top speed of 50 km/h.
^ Maximum towing distance is 50 km.
^ For longer towing distances, the vehicle must be raised at the rear axle and the drive shaft (cardan shaft) must be removed. Alternative (instead of removing the cardan shaft): The vehicle would have to be raised to such an extent that the wheels on the raised rear axle can turn freely.