15 Excessive Speed n2 or n3
P0701
15 Excessive speed n2 or n3
A check is carried out to ascertain whether the n2 sensor signal or the n3 sensor signal exceed a limit value. The aim of the fault detection is to detect a hydraulic or mechanical malfunction of the transmission.
NOTE: The frictional connection is interrupted by the Tiptronic control module.
Diagnosis conditions
- Ignition on
- n2 > 7000 rpm or n3 > 7000 rpm
Possible fault cause
- Mechanical fault in the front planetary gears
- Excessive speed sensor n3 or outer disk bracket faulty
Diagnosis/Troubleshooting
49 Excessive speed engine
The CAN engine speed signal is checked to ascertain whether a limit value is exceeded. The aim of the fault detection is to detect a hydraulic or mechanical malfunction of the transmission.
NOTE: The frictional connection is interrupted by the Tiptronic control module.
Diagnosis conditions
- Ignition on
- Engine speed > maximum switch speed + offset (e.g. max. switch speed = 6000 rpm, offset = 500 rpm)
Possible fault cause
- Mechanical fault in the front planetary gears
Diagnosis/Troubleshooting
50 Impermissible transmission ratio
The transmission is checked to ascertain whether it shifts down as permissible.
NOTE: The frictional connection is interrupted by the Tiptronic control module.
Diagnosis conditions
- Ignition on
Possible fault cause
- Mechanical fault in the front planetary gears
Diagnosis/Troubleshooting
51 Transmission slips or gear implausible
Checks are carried out to ascertain whether a gear is implausible or the transmission slips.
NOTE: The redundancy transistor is switched off. The set point values of the current regulator are set to 0 and all change-over valves are switched off. The control module is then in emergency operation. Minimal cycle is additionally activated.
Diagnosis conditions
- Ignition on
- No active gearshift
- No speed n2 fault
- Engine speed n2 > 150 rpm
- No selector lever fault
- No CAN fault
- No PSM fault
- At least one plausible rear wheel speed
- All plausible PSM wheel speeds > 50 rpm
- Difference between right and left wheel speed less then 100 rpm (rear and front)
- Output shaft speed > 180 rpm
- Engine speed > 450 rpm
Possible fault cause
- Leak in hydraulic wiring
- Leak in mechanical transmission parts
- Oil filter missing
Diagnosis/Troubleshooting
