2010 Porsche Panamera Turbo (970) V8-4.8L Turbo A L L Diagnostic Trouble Codes ( DTC ): P Code Charts Page 693
- Ignition on
Possible fault causes
- Fault in CAN bus
Fault setting conditions
- Torque intervention not possible
Fault effects
- Transmission limp-home indication in instrument cluster control unit
Positive Engine Torque Intervention Not Possible
P1991
Diagnosis information - PDK
Positive engine torque intervention not possible
Diagnostic conditions
The control unit initially tests internal function sequences when the ignition is switched on (terminal 15). If they are OK, all diagnosable outputs are
then tested and any faults are stored.
- Ignition on
Possible fault causes
- Fault in CAN bus
- DME control unit detects engine fault
Fault setting conditions
- Torque intervention not possible
Fault effects
- Transmission limp-home indication in instrument cluster control unit
Software Monitoring A Of Signal Processing Unit
P1991
Diagnosis information - PDK
Software monitoring A of signal processing unit
Diagnostic conditions
The control unit initially tests internal function sequences when the ignition is switched on (terminal 15). If they are OK, all diagnosable outputs are
then tested and any faults are stored.
- Ignition on
Possible fault causes
- PDK control unit faulty
Fault setting conditions
- Complement error
Fault effects
- CAN alive counter freeze
- Engine speed limitation
- Transmission limp-home indication in instrument cluster control unit
Software Monitoring B Of Signal Processing Unit
P1991
Diagnosis information - PDK
Software monitoring B of signal processing unit
Diagnostic conditions
The control unit initially tests internal function sequences when the ignition is switched on (terminal 15). If they are OK, all diagnosable outputs are
then tested and any faults are stored.