DTC B120: Twilight Delay Switch Pot Circuit: Intermittents
If an intermittent Code B120 is being set manipulate the related wiring while observing BCM data parameter BD43. See DATA DISPLAY PROCEDURE under DIAGNOSTIC MODES under SELF-DIAGNOSTIC SYSTEM, for a list of BCM Data Parameters. If the failure is induced, the reading. Will jump from its normal value to a reading outside the range of 6-94%.
NOTE:
The following numbered steps refer to circled numbers on diagnostic chart. See Fig 1. For circuit identification, see Fig 2.
- BCM data value BD43 displays twilight delay time. The normal range is 6-94%.
- Checks to see if the open or grounded circuit reading is due to the circuit or the switch. If the open or grounded circuit reading changes from a short to voltage reading after jumping the switch assembly terminals, the BCM and wiring are okay.
- Measuring between circuit No. 705 (5 volts) and circuit No. 271. This will determine if circuit No. 271 is open or shorted to ground.
- Checks to see if the short to voltage circuit reading is due to the circuit or the switch assembly. If a short to voltage reading changes to an open circuit reading after disconnecting the switch assembly, the BCM and wiring are okay.
NOTE:
When all diagnosis and repairs are completed, clear codes and verify operation.