Control Module Malfunctions
WARNING: This page is about a different car, the 2003 Jaguar XJR, 2002 Jaguar XJR, and 2001 Jaguar XJR. However, it is still accessible from the selected car via links, so may be relevant.
The diagnostic detects malfunctions in the TCM ignition switched supply by measuring the system voltage. A fault is logged if the voltage is either too high or too low. The voltage is measured at the TCM.