DTC 71, Camshaft Position Sensor Circuit Low (4L80-E W/ TCM): Notes

Camshaft position sensor detects rotational speed of camshaft. As camshaft rotates, an AC signal is generated in circuit. This signal provides input to determine engine speed, for use in various calculations including TCC slip speed and overdrive ratio. DTC 71 will set when:

• DTC 28 is not set.
• Engine speed less than 50 RPM.
• Trans. range indicates Reverse, D4, D3 or D1.
• Conditions are met for 2 seconds. PCM will default to inhibit TCC.
  NOTE: Test numbers refer to numbers on diagnostic chart.

1. An out-of-range trans. range pressure switch could falsely indicate actual transmission range.
2. This checks entire CMP sensor circuit for proper signal.
3. A signal at this point indicates sensor is capable of inducing an AC voltage in circuit.