P188A-98 Differential Oil Temperature Too High/Too Low - Component or system over temperature: Action

NOTE: If this DTC has logged together with a ROM error DTC (P0605-00), the ROM error is the likely root cause. Refer to the DTC helptext for DTC P0605-00 and rectify this fault first before proceeding further

Check the operation of the rear differential. Refer to the relevant section of the workshop manual and check the rear differential oil quantity and specification. Rectify as required, clear DTC and retest
If fault persists, clear DTC, allow the vehicle to cool for at least 1 hour, then retest. If DTC persists, refer to the electrical circuit diagrams and check the rear differential oil temperature sensor connectors and circuits for short circuit to ground, short circuit to power, short circuit to one another, open circuit, high resistance. Repair circuit as required. Clear DTC and retest
If no circuit problems exist or if fault persists, check and install a new rear differential oil temperature sensor as required