P0725

P0725 71

Engine Speed. Bus Data Unreliable

Fault symptom
- Gearbox warning lamp lights in MIU.
- Messages shown in SID.
- Limited shifting function.

On-board diagnosis

Type of diagnosis:
- Continuous

Enable criteria:
- Engine running.
- Input shaft speed exceeds 500 rpm.
- No bus communication fault with engine management system.
- "Limp home" function not active.

Fault criteria:
- Incorrect engine speed signal from engine management system for more than 4 s.

System reaction to a fault:
- Limp home

OK report:
- Engine speed signal valid for more than 5 min.

Diagnostic help
- If engine management system self-diagnostics detects a fault on the crankshaft position sensor, the speed signal on the bus becomes invalid. When the engine management system approves the speed signal, the correct value is transmitted on the bus. When P0725 71 is generated in TCM, DTC P0335/P0336/P0337/P0339 is stored in the engine management system.
- Follow the fault tracing procedure for the DTC in question in the engine management system.