ENGINE SPEED INPUT - P0726/P0727
The engine speed input signal is a square wave output from the ECM. The signal is 12 volt active high with a duty cycle of 50°/120° of crankshaft revolution i.e. 3 pulses per revolution. The frequency of the signal is proportional to engine speed.

Engine Speed Input Circuit - Range/Performance P0726
Engine speed is continuously monitored by the background diagnostics. This fault is flagged if the engine speed exceeds the maximum speed threshold (approx 6800 rpm) . This fault code would suggest an intermittent fault in the circuit.

Engine Speed Input Circuit No Signal - P0727
If the engine speed drops below 95 rpm and the selected gear is not P or N, then the TCM will initiate the default mode. This fault code will only be stored if the output speed is greater than 300 rpm . This is to prevent spurious flagging of codes if the engine stalls.

Possible Causes :
Faulty harness wiring 1 connectors.
Faulty signal from ECM.

Effects :
MIL illuminated.
Transmission warning lamp illuminated.
Maximum fluid pressure applied.
Limp home mode applied.

Remedy :
Repair or renew harness 1 connectors.
Examine ECM fault diagnosis.




Troubleshooting Schematic

Key To Schematic Diagrams

Transmission Control Module (TCM)
Transmission Unit
TCM Multi-pin Connector
Transmission Rotary Switch
Transmission Connector Plug
Engine Control Module
Instrument Pack
ABS/Traction Control Control Module
Kickdown Switch