Gearbox Interface Unit (GIU) (Automatic gearbox - EM-CVT) (page 2 of 2)

The GIU is located in the in the LH side of the luggage compartment behind the trim. The GIU has two captive studs which are secured to the body with two nuts.

Permanent battery voltage is supplied to the GIU from fuse 2 in the engine compartment fusebox via a 10 Amp in-line fuse located on the harness near the GIU connector.

The GIU responds to control messages from the ECM to control the gearbox operation. The GIU also passes messages to the ECM in response to driver input commands enabling the ECM to operate the gearbox accordingly.

The ECM and GIU have a programmed default strategy which is engaged when specific faults are detected. Any condition requiring the default strategy will be relayed to the driver by illumination of the gearbox fault lamp in the instrument pack.

The ECM will need to learn the ratio control motor position when a new ECM is fitted. This is performed automatically by the ECM using a fast adaptation procedure. Refer to Operation section for details.

A ’limp-home mode’ is provided if the system detects a fault but is still able to control the gearbox ratio. In addition to the fault lamp illumination, the driver will experience the engine speed being limited to approximately 3000 rev/min.

If the system is unable to control the gearbox ratio, the ECM will be unable to implement the default strategy, the gearbox will remain in a single ratio and the fault lamp will illuminate. If in the lowest gear, the engine speed will increase rapidly to 6000 rev/min and vehicle speed will be limited to a maximum of 30 mph (48.3 km/h). If in the highest gear, the driver will experience very slow acceleration and engine speeds of approximately 2000 to 2250 rev/min at 50 mph (80.5 km/h).

A single multiplug provides all input and outputs connection to and from the GIU. The following table shows the harness connector pin numbers and input/output information.