Tachometer Inoperative for Cadillac DeVille 1999
Circuit Description
The IPC monitors the tachometer sent by the PCM through CKT 121
(WHT). The IPC software controls one of the following two display types:
| • | A message display with a digital IPC |
| • | An analog gauge with an analog IPC, consisting of a needle pointer |
The IPC interpolates and scales the tachometer information received
from the PCM.
Diagnostic Aids
| • | Connect a scan tool to the DLC. |
| • | Test for any set DTCs if no DTCs are set current. |
| • | Test CKT 121 (WHT) for an open or short. |
