00538

00538 - Reference voltage

00538 - Reference voltage : Signal too small

Possible Cause

• Short circuit or open circuit in wiring or connectors. Pay special attention to the wires from contact 8 of connector housing T16b on Climatronic control module -J255- to flap motors.
  

Possible Solutions

• Check wiring and connectors to control module using wiring diagram
  
• Check function of flap motors for regulating air conditioner using function 03 Output Diagnostic Test Mode (DTM).
  

Possible Cause

• Flap position sensors -G92-, -G112-, -G113- or -G114- malfunctioning.
  

Possible Solutions

• Disconnect electrical connectors to listed sensors one after another, erase DTC memory and check DTC memory again. If the "Reference voltage" malfunction is no longer recognized (and the DTC reappears after reconnecting), the applicable flap motor must be replaced.
  

Possible Cause

• Control module malfunctioning.
  

Possible Solutions

• Replace control module if necessary.