Code 24 - VSS Circuit
Code No. 24 will set if constant voltage exists on circuit 38, engine speed is within 2400-4400 RPM and low load condition exists. All conditions must exist for at least 10 seconds.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- This checks ECM voltage on circuit No. 38. During wheel rotation the pulsing action will produce a varying voltage. Voltage variation will be greater at low speeds with an average of 4-6 volts at approximately 20 mph.
- Voltage of less than one volt on circuit No. 38 at ECM connector indicates a short in the circuit. Disconnect circuit No. 38 at speed sensor. If voltage now exceeds 10 volts, speed sensor is defective. If voltage remains less than 10 volts, check for ground in the circuit. If circuit is not grounded, check for defective ECM connector or ECM.
- Steady voltage of 8-12 volts at ECM connector indicates that open exists in circuit No. 38 or speed sensor is defective.