Troubleshooting No. 2

WARNING: This page is about a different car, the 2004 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

CLOCK LOSES OR GAINS TIME
1. Check that the battery positive voltage is 10 - 16 V.
  If voltage is not as specified, replace the battery.
2. Inspect the error of the clock.
  Allowable error (per day): +/-1.5 seconds
  
  If the error exceeds the allowable error, replace the multi display.
3. Check if the clock adjusting button is sticking in position and has failed to return. If the error exceeds the allowable error, replace the multi display.
4. Troubleshoot the clock as follows.
  HINT:
  
  Inspect the connector on the wire harness side.
  
  Fig 1: Connector On Wire Harness Side Flow Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002