Powertrain, generic · Transmission

P0793 Intermediate Shaft Speed Sensor A Circuit No Signal

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

The intermediate shaft speed sensor measures a shaft between input and output – a countershaft on Toyota's U760 six-speed, the intermediate shaft behind the overdrive set on Ford's 5R110W. Together with turbine and output speed it lets the module check each gear stage and control clutch slip. P0793 means there is no pulse signal from the intermediate shaft sensor although the vehicle is moving according to other speeds. Toyota's bulletin for the U760 six-speed lists P0793 with P0717 and P0791 and replaces the countershaft sensor with a revised part. Ford reports the same fault under P0791 (below 250 rpm for 5 s). Note that a 2007 Allison table's 'P0793' for shift solenoid 1 low is a typo for P0973. Limp mode and check engine light follow.

Likely causes

Sensor faulty (internal open circuit)
Wire open or connector loose
Reluctor wheel or air gap
Transmission module

Symptoms

  • Check engine light
  • Limp mode
  • Harsh shifts
  • Accompanying codes P0717/P0791

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–600
Time1.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

intermediate shaft speed sensorsensor wiringtransmission control module

Related codes

P0791P0792P0794P0717P0722

References: http:, newtonnet.co.uk, law.cornell.edu.