Power Take-Off Switch and Circuit

The Power Take-Off (PTO) circuit is used by the PCM to disable some of the OBD II Monitors during PTO operation. The PTO circuit normally carries low voltage. When the PTO switch is on/closed, B+ is supplied to the PTO input circuit indicating to the PCM that an additional load is being applied to the engine. If this action was not reported by the PTO circuit, a false Diagnostic Trouble Code may be stored.