Test G: Transmission Control Indicator Light Inoperative

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Mazda B4000, 2003 Mazda B3000, 2003 Mazda B2300, 2002 Mazda B4000, and 2002 Mazda B3000. However, it is still accessible from the selected car via links, so may be relevant.

Perform KEY ON ENGINE RUNNING SELF-TEST . If DTC P1780 is not present, go to next step. If DTC P1780 is present, perform TEST TB: TRANSMISSION CONTROL SWITCH IS NOT OPERATING CORRECTLY (EXCEPT MAZDA & RANGER) or TEST TB: TRANSMISSION CONTROL SWITCH IS NOT OPERATING CORRECTLY (MAZDA & RANGER) .
Turn ignition switch to OFF position. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install breakout box. Turn ignition switch to ON position. Measure voltage between breakout box terminal No. 79 and terminals No. 24 and 76. If voltage is more than 2 volts, replace PCM. If voltage is 2 volts or less, check indicator bulb and fuse. Repair as necessary. If bulb and fuse are okay, repair open circuit between PCM connector TCIL terminal and ignition switch.